About this volume

This volume may serve as a companion to the two books Against the Physicists by Sextus Empiricus. These books, which offer a sceptical discussion of the main concepts of ancient physics, are part of a collection of five books Against the Dogmatists (Adversus Dogmaticos), which are in their turn nowadays known as part of a larger work, Against the Mathematicians in eleven books. It is usually assumed that Sextus lived and worked in the second century ad,Footnote ¹ and his works are our main source of information on Pyrrhonism, the particular brand of scepticism that flourished between the first century bc and Sextus' own days, that appears to have dwindled away in later antiquity to become virtually unknown in the Latin Middle Ages, but that made a remarkable comeback in the early modern period.Footnote ²

In the past the rich text of Against the Physicists has not received much attention in its own right, apart from a few isolated contributions on special subjects.Footnote ³ It has mostly and primarily been mined as a quarry of information on earlier philosophies, especially on the Hellenistic schools. On the other hand, and for obvious reasons, modern scholars' engagement with Sextus' own philosophical position has usually centred on the more systematic first book of his Outlines of Pyrrhonism, in which he describes Pyrrhonian scepticism as a ‘way of life’, setting it off against other philosophical positions and describing its method and terminology.

Their specialized subject matter notwithstanding, the two books Against the Physicists should be regarded as part of Sextus' overall sceptical project. After all, Pyrrhonian scepticism is more than just an epistemological position. In so far as it constitutes a ‘way of life’ (diagōgē) it involves an ongoing engagement with logic, physics and ethics, but also with the knowledge claims of grammar, rhetoric and the mathematical sciences. In the end it is the consistent and ongoing process of constructing a diaphōnia of opposing accounts of equal strength in all these areas that will inevitably lead to the sceptic's suspension of judgment (epochē), resulting in a state of tranquillity (ataraxia).Footnote ⁴ Hence the following description of Pyrrhonian physics:

This volume aims to study how the two books Against the Physicists carry out this project in practice. Even if, as we saw, this to some extent constitutes a novel approach to this text, it goes without saying that the authors of the various contributions have gratefully used the results of the renewed interest in Pyrrhonism in general that we have witnessed over the last three decades or so.Footnote ⁵

Each of the chapters covers one of the individual topic-related sections in Sextus' text, which means that the book as a whole covers all of Against the Physicists and may indeed serve as a philosophical running commentary to it.Footnote ⁶ In accordance with this overall design, the present Introduction does not attempt to introduce and summarize the individual contributions but aims to offer some thematic inroads into a number of general issues that cut across the individual chapters. It covers the place of Against the Physicists within the whole of Sextus' philosophical output, in particular the relation between this work and the partly parallel sections in book 3 of Outlines of Pyrrhonism, the general structure of the text, the sceptical strategies within the individual chapters, the main types of argument used by Sextus, and the question of his sources. Some of these issues are matters of controversy, also between the contributors to this volume. Accordingly, readers should not expect the individual contributions to be governed in all respects by a single overarching view on Sextus and his methods and purposes. Nor should they assume that the views put forward in this Introduction are necessarily shared by all contributors. The aim of this Introduction is to set the stage, to connect some of the main themes that recur in the various contributions, to raise some questions and offer some possible answers. Cross-references to the individual chapters will help the reader to trace agreements and disagreements on points of detail.

Sextus and his two books Against the Physicists

The title of the two books Against the Physicists does not appear to be of Sextus' own making, although he does seem to refer to these books by the descriptive label ‘notes against the physicists’ (M 1.35; 3.116). Together with two books Against the Logicians and one book Against the Ethicists, they constitute a collection of five books Against the Dogmatists (Adversus Dogmaticos). In the manuscript tradition these five books, which contain a sceptical discussion of the most relevant subjects in the three main areas of philosophy, came to be appended to six books Against the Mathematicians or (alternative translation of the Greek) Against the Professors (Adversus Mathematicos), which contain a sceptical discussion of the knowledge claims of the liberal arts. As a result they were later generally referred to as books 7–11 of Adversus Mathematicos. Of these M 7 and 8 are the two books also entitled Against the Logicians, M 9 and 10 are our two books Against the Physicists, and M 11 is Against the Ethicists.

Sextus also wrote three books of Outlines of Pyrrhonism (Purrhōneioi Hupotupōseis) of which the first offers a neat and fairly systematic outline of Pyrrhonian scepticism and the way in which it relates to other philosophies, whereas the second and third books offer a sceptical discussion of the principles of dogmatic philosophy: logic in book 2, physics and ethics in book 3. Elsewhere he refers to some other works which are now lost: the Empirical Notes (Empeirika Hupomnēmata, referred to at M 1.61), possibly identical with the Medical Notes (Iatrika Hupomnēmata, referred to at M 7.202), and a treatise On the Soul (Peri Psuchēs) which may or may not have been a separate work (referred to at M 6.55 and M 10.284).

The surviving material accordingly consists of three corpora:

1. (1) M 1–6,

2. (2) M 7–11, and

3. (3) PH 1–3.

Our two books Against the Physicists belong to (2). About this second corpus and how it relates to (1) the following observations can be made:

1. (a) It is likely that (2) should as a whole be identified as (part of) a work to which (1) refers as the Sceptical Notes (Skeptika Hupomnēmata; references at M 1.29; 2.106; 6.52); this suggests both that (1) and (2) were conceived as different works and that (2) antedates (1).

2. (b) As noted above, there are what appear to be specific backward references to our two books Against the Physicists in (1), namely in M 1.35 and 3.116, which seem to confirm the chronological priority of (2).Footnote ⁷

3. (c) There are (more or less close) parallels between the texts of (1) and (2); thus the sections on wholes and parts, body, number and time in our two books Against the Physicists contain passages that are paralleled within the mathematical sections of (1); this becomes understandable once one realizes that the latter focus to a large extent on mathematics as applied in physics.Footnote ⁸

4. (d) The original collection of Skeptika Hupomnēmata may well have been larger than (2), that is, larger than the remaining five books of M 7–11, for Diogenes Laertius 9.116 (and a corresponding passage in the Suda) refers to it as a work in ten books;Footnote ⁹ and it is possible that this work started out with a general account of Pyrrhonism, comparable to what we find in PH 1.Footnote ¹⁰

An even larger number of parallels can be detected between the corpora (2) and (3) and in this case the relative chronology has proved to be a matter of controversy. PH is a hupotupōsis, a relatively short and elegant account in outline. It consists of two parts: book 1 deals with what Sextus calls the katholou logos (or ‘general account’) of Pyrrhonian scepticism, namely an exposition of the nature of the sceptical position, the modes used by sceptics, and the differences between these sceptics and other schools.Footnote ¹¹ Books 2 and 3 then give the eidikos logos (the ‘special account’), the sceptical way of dealing with a host of individual subjects. M, by contrast, is a collection of hupomnēmata, ‘treatises’ or even ‘notes’,Footnote ¹² in its present form exclusively covering the ‘special’ account.Footnote ¹³ With its five books it is more than twice the size of the ‘special’ section of PH. As noted, numerous parallels exist between M and this ‘special’ section of PH, but it can also be observed that on the whole PH seems to be better organized, as one might perhaps expect, given the difference between a hupotupōsis and a collection of hupomnēmata. Indeed, PH contains various statements on Sextus' part to the effect that the work only gives an outline (PH 1.4), that he accordingly only gives ‘few out of many examples’ and that he is concerned to be brief (PH 1.163),Footnote ¹⁴ whereas M shows no such restrictions. At the end of the final book 11 of M, the Against the Ethicists, Sextus claims that he has completed his journey (diexodos) through the sceptic system (or rather: ‘way of life’ (diagōgē), 11.257), thereby implying that he has not merely given a selection, but a complete guided tour.

For quite some time the communis opinio among scholars appears to have been, for the most part on the basis of stylistic investigations of Janáček, that PH was the earlier work and that M 7–11 should be regarded as a kind of ‘blow-up’, with additions and changes, of PH 2 and 3.Footnote ¹⁵ This ‘standard’ chronology (with the sequence (1) PH, (2) M 7–11, (3) M 1–6) has been doubted or criticized by various scholars, among them Richard Bett, who has made the most elaborate case for a revised chronology according to which PH postdates M. The main arguments that have been used to suggest that PH must be the later work are:

1. (i) the stylistic differences between the two works as noted by Janáček (which as such are taken to show that the two works must belong to different periods, though not necessarily which of the two is the earlier one: Bett reverses Janáček's chronology);

2. (ii) the fact that M may be seen to show traces of an earlier form of Pyrrhonism which is no longer present in PH; and

3. (iii) the fact that the structure of PH is more achieved and polished.Footnote ¹⁶

As is often the case with questions like these, none of these arguments is really conclusive when taken by itself. As we have just seen, the stylistic argument (i) has been used to argue both ways, so it does not naturally and obviously favour one particular relative chronology. Argument (ii) may look more promising, but below (pp. 21–2) we will raise some doubts on whether the differences between the two treatises are really significant in this respect and on whether they can be taken to point to different chronological stages (corresponding to a changed attitude on Sextus' part with respect to the alleged earlier form of Pyrrhonism or the way in which it expressed itself) at all. This leaves us for the moment with argument (iii), which certainly has some prima facie plausibility. PH is in many respects the better-ordered text, and why should we not assume that the better-ordered text is the later one? Moreover, a passage such as PH 3.56, referred to above,Footnote ¹⁷ which claims that Sextus will here not deal with all arguments in detail, may be taken to suggest that he has a store of these arguments available, and why would not this larger storehouse be M 9 and 10? On the other hand, there is no need to assume a priori that one of our two works must be a revised version of the other one.Footnote ¹⁸ It is very well conceivable that Sextus in the end had an even larger store of arguments at his disposal than we find in M, and his selection from this collection may just have been different for PH on the one hand and for M on the other, in accordance with the different purposes of the two treatises.Footnote ¹⁹

Especially since there are no unambiguous cross-references between the two works, it appears that the question of chronological priority is hard to settle, and it will no doubt not be settled by the present volume either.Footnote ²⁰ The readers should judge for themselves. Richard Bett makes a strong case for his views in the first chapter of this book. Other authors show some reservations on points of detail and adduce passages in M that make it hard to believe that the counterpart in PH must be the later version, or in general that any one of the two treatises should be seen as the source for the other.Footnote ²¹ We will definitely need more detailed investigations of this kind if we are ever going to be able to clinch the issue. In the meantime, we should perhaps not unduly and exclusively focus our attention on the question of the relative chronology of the two works, and we should also envisage the possibility of explaining the differences between the two treatises in terms of the different use of common sources, the possible use of different sources and the differences in purpose and ‘type of discourse’ between the two works.

The structure of Against the Physicists

The two books Against the Physicists provide a sceptical discussion of dogmatic physics, or physical theory. Sextus starts out (9.1) with a reference to a passage in Against the Logicians (M 7.20–4), where he had argued that although physics is the older discipline, logic should be treated first, since it claims to offer a theory of criteria and proofs and as such may serve as the basis for all further philosophizing. Hence Against the Physicists is made to follow Against the Logicians. The ensuing discussion of physics is then presented as an attack in broad outlines: ‘we shall attack the most important and most comprehensive (kuriōtata kai sunektikōtata) dogmas as in the doubts cast on these we shall find the rest also included’ (M 9.1).Footnote ²² This is why the procedure can be compared to an attack on the foundations of a wall in a siege (M 9.2).

This focus on what is most comprehensive should not be taken to mean that the text contains no detailed arguments, for it abounds with them. The point is rather that the text focuses not on the details of the individual physical theories – as Academics like Clitomachus had done, for argument's sake even sometimes taking for granted aspects of their opponent's theory (M 10.1) – but offers a broadside attack on a number of key concepts which are used in the various systems and without which the systems would collapse. This will allow the author, indirectly, to cast doubt on more specific physical tenets as well: he will catch them all in one go, so to speak, just as people do who hunt or fish with a net, as opposed to those who pursue the quarry on an individual basis (M 10.3).

The key concepts that Sextus discusses are: god (9.1–195), cause (9.195–330), wholes and parts (9.331–58), body (9.359–66), place (10.1–36), motion (10.37–168), time (10.169–247), number (10.248–309) and coming-to-be and passing-away (10.310–50). The comparison, in the introduction, of these key concepts to the foundations of a city wall leads us to expect that, being the foundations of physics, they are somehow interconnected, and that the individual sections discussing each of them are also interconnected. To some extent this is indeed the case: we find some signposting in these two books which suggests that Sextus has a kind of coherent skeleton, or overall design, in mind, or at least that he wanted to suggest that such a skeleton can be thought up. The following overview – with the references to the main sections in bold print to make them stand out – may serve to show how this skeleton is fleshed out in actual practice.

Active and passive principles or causes are recognized by all who do physics (M 9.4). So we should start with these. But before starting with these, we may discuss a special case of an active cause: god (9.1–195). The discussion of god thus in a way prefaces the more general discussion of active and passive principles or causes (9.195–330). Being passive is connected with being affected (in a process of change or alteration), and being affected is a matter of something being added or subtracted (9.277). Since subtraction and addition, in their turn, involve the idea of wholes and parts (9.330),Footnote ²³ we need a discussion of wholes and parts (9.331–58). The latter discussion is accordingly presented as somehow subservient to the discussion about addition and subtraction, and eo ipso to the discussion of active and passive causes. After all, it is argued, the difficulties concerning wholes and parts will add to the doubts already signalled in connection with subtraction and addition and with active and passive causes (9.330).Footnote ²⁴ So we have a connection between the first three subjects: god (as a special case of the active cause), active and passive causes as such, wholes and parts as concepts required in the explanation of subtraction and addition and hence also in the explanation of the process of being affected by an active cause.

This part of book 9 (i.e. the first three sections) winds up in 9.358 with the claim that all this has been a discussion of the active principles (drastēriai dunameis), and that we will now proceed with a section that ‘touches on both the active and the material principles jointly (koinoteron)’ (M 9.358). This reads like a rather forced ex post way of linking the first three sections (on god, active and passive causes, parts and wholes) with the next section on body (9.359–440). For, as we saw, the first three sections covered more than ‘active principles’ alone, although all subjects covered were somehow linked to the notion of an active cause. Moreover, the section which now follows, on body, hardly deals with body as connected with active and passive causation. It starts with a doxographical overview on first principles (archikōtata stoicheia) which seems to cut across the categories of active and passive causation, offering a diaeresis of first principles into (a) bodies and (b) incorporeals.Footnote ²⁵ It then, in narrowing its focus on body, briefly brings in the notion of active and passive causation, but only in order to do away with the definition of body as that which is capable of being affected (9.366).Footnote ²⁶ It goes on to discuss body as defined by ‘the mathematicians’, namely as ‘that which has three dimensions, length, depth and breadth’ (9.337), and this explicitly non-physical discussion, which has nothing to do with either active or passive causes, takes up the rest of the section. So the connection between this section on body and the first ones on causation appears to be rather thin.

Now, according to the doxographical part of this section on body (9.359–66) some say the first principles of things are bodies, others that they are incorporeals (such as numbers, surfaces, Ideas), and this division appears to provide the structure for the subsequent part of the discussion; for following on the discussion of body proper (9.366–440), book 10 goes on to address the incorporeals (as is explicitly announced at M 9.440). Nevertheless, there are some oddities in this part of the discussion as well. First, as we saw, the discussion of body very quickly transforms itself into a discussion of mathematical body, and in that connection it takes along surface, one of the incorporeals, as well. Secondly, the subject matter of the following sections, which are explicitly devoted to the incorporeals, does not match with the set of incorporeals mentioned in the doxographical overview (9.364). The latter comprised numbers, surfaces and Ideas. Yet, number is now the only item from this original set which is being covered. Ideas are not discussed at all. Instead we have discussions of place, motion, time, number and coming-to-be and passing-away, four of which did not figure in the original list, whereas it is not even clear whether motion and coming-to-be and passing-away are to be considered as incorporeals at all. So there is a certain mismatch between the ‘programme’ that has been announced and the actual material that is being presented. In the meantime a possible reason for this mismatch suggests itself as well: Sextus' dependence on his sources. Presumably the available material, both on body and on individual incorporeals, did not really fit the preconceived structure, which, as we saw, is itself dependent on a doxographical overview. We shall have to see whether this suspicion is confirmed by the rest of what we find in these two books Against the Physicists.

At the end of the account of bodies (9.440) the account of incorporeals is announced, and book 10 starts out by claiming that after the foregoing discussion of body and limits, criticizing both physicists and geometers, the investigation of place seems to follow next, ‘for it is maintained by all of them with one accord that body either is contained in place or moves in place’. Here again, the connection is slightly strained, for ‘all of them’ cannot strictly speaking be taken to refer to physicists and geometers alike, the latter having as such no views on the emplacement of physical bodies. The concept of place is rather something that is connected with the physical discussion of bodies, a subject that, as we saw, was hardly covered in the preceding section. Once again, Sextus is trying his best to suggest a systematic connection between topics which is narrower than is justified by the actual contents of what he presents.

The discussion of place (10.1–36), then, is justified by the claim that ‘all’ agree that bodies move in place or are contained in place. The discussion of motion (10.37–168) which then follows is naturally linked to the discussion of place, because motion is the type of change that involves place: it is change (kineisthai) in the sense of ‘change with regard to place’ (kata topon kineisthai, 10.36). The fact that place is said to have been ‘abolished’ in what precedes is apparently insufficient in itself to prove that there can be no satisfactory account of ‘change with regard to place’ either. Indeed even the fact that next to the notion of place also the notion of body has been established as problematic is not in itself sufficient to undermine the account of motion as motion of a body in place: it is given a separate refutation. What is more, the fact that motion is not just the motion of a body changing place but also occurs in time (10.169) is said to offer occasion for a separate discussion of time (10.169–247). Since, in its turn, the measurement of time involves number, the next subject for discussion is number (10.248–309). Yet, here we run into another oddity: the discussion of number which now follows does not treat it in the ordinary arithmetical sense in which number may be said to be connected with time or motion but instead embarks on a critical discussion of what we might call number metaphysics of a Pythagorean or Platonic bent. Here we have one more instance where the contents of a chapter do not match with its place within the structure of the overall argument of the book as suggested by Sextus. By now our initial suspicion that it is primarily the nature of the available source material which has determined the contents and much of the internal structure of his discussion seems hard to put aside.

The final section of M 10, on coming-to-be and passing-away (M 10.310–50) is introduced without any explicit linkage to what precedes, but such a linkage is provided later on, at 10.319–25. This time, however, we are not told that the discussion of coming-to-be and passing-away is in a sense required by the discussion of one or more concepts that preceded it. We are told, instead, that a discussion of coming-to-be and passing-away is in a sense made superfluous by what precedes, for ‘the main point has already been established by our previous arguments’ (10.319). After all, it is claimed, we have established the untenability of the notions of time, change (or motion), causes, subtraction and addition, and touch (apparently a reference to M 9.258ff.), all of which are necessary to explain the notions of coming-to-be and passing-away. Nevertheless, the subject of coming-to-be and passing-away apparently deserves to be discussed in its own right, and this discussion of change in the most general sense (and as the central subject of physics) may even be said to crown books 9 and 10.Footnote ²⁷ All the concepts that have been discussed previously are involved in attempts to deal with this final subject, and as a result the earlier discussions all contribute to demolishing the prospects of making philosophical sense of the notions of coming-to-be and passing-away.

We may conclude that the structure of M 9 and 10 in some respects offers a slightly haphazard aspect. In dealing with Diogenes Laertius 9 and its relation to its sources, Jonathan Barnes usefully distinguished two extreme views on how a writer like Diogenes should be positioned in relation to his source or sources.Footnote ²⁸ On one extreme there is what Barnes calls ‘naive conservatism’, according to which the work is in a strong sense the work of its author: Diogenes (in this case) is then taken to have read the relevant sources, made notes, organized his own ideas and then to have written his text. On the other hand, there is what may be labelled ‘naive radicalism’, which holds that Diogenes simply copied out some earlier work or works. Of course various positions in between these extremes can be envisaged, and indeed Sextus as an author does seem to take up such an intermediate position. On the one hand, he seems to be conscious of the way in which his various topics hang together and of the fact that treating them as interconnected is philosophically justified. And, as we saw, he does try to impose some kind of general structure, which is meant to bring out these connections. On the other hand, the material on which he draws does not allow him to let these connections shine through as clearly as one would perhaps wish. Nor does he use his own conception of how the various topics hang together in order to have them eliminate each other, although there are some passages where this possibility is at least hinted at, as in the case of coming-to-be and passing-away.Footnote ²⁹ Instead, it appears that the structure of what he found in his sources to a considerable degree co-determines the structure of his account. To a certain extent this also goes for the internal structure of the separate chapters. Why is it only in the case of the section on god that we are given a separate preliminary section on the various views on how people acquired the relevant notion (i.e. ‘god’) in the first place (with accompanying refutation of all these views)? Presumably because Sextus' text here ultimately goes back to an Academic account, focusing on the theological discussions between Stoics and Academics, and for some Stoics the question ‘how do people acquire the notion of god’ was indeed a separate question in their theology, as Cicero's account in On the Nature of the Gods makes clear.Footnote ³⁰ And why is the section on place the only one to start out with a separate section on the ‘conception’ (noēsis) of the subject at issue, namely place, which then turns out to be incomplete, because it does not cover the Aristotelian position? Because it allowed Sextus to integrate, en bloc, two sets of definitions from the doxographical tradition on how Stoics and Epicureans differentiated between the notions of place, void and space. All in all, it turns out to be a fair guess that it is primarily this strong dependence on the contents and structure of his sources that is responsible for what we called the rather haphazard impression M 9 and 10 make on the reader.

Sextus' own role in organizing his material seems to be definitely stronger in the counterpart to M 9 and 10 which we find in the first half of PH 3. There we start out with a more coherent section on causation – with subsections on efficient principles (PH 3.1), god as efficient cause par excellence (3.2–12), cause (3.13–16), causation (3.17–29) and material principles or ‘elements’, which must be either corporeal or incorporeal (3.30–7), and the ‘inapprehensibility’ of body (3.38–62, including as a rider a discussion of the inapprehensibility of incorporeals as such, 3.49–55, and a discussion of compound bodies as formed by contact, touch, mixture or blending, 3.56–62). Then we turn to change (3.63–118), with subsections on its subspecies locomotion (3.64–81), increase and decrease (3.82–4), subtraction and addition (3.85–96), transposition (3.97) and on wholes and parts (3.98–101), physical alteration (3.102–8) and coming-to-be and passing-away (3.109–14), but also on rest (3.115–18). Finally the text discusses the necessary conditions for change, namely place (3.119–35) and time (3.136–50), two incorporeals that apparently deserve a discussion in their own right apart from the general discussion of the inapprehensibility of incorporeals that has preceded, and number as a concomitant of time (3.151–67). The ordering of the subjects is thus more systematic – moving from kinds of causes to bodies and compounds of bodies to kinds of change to kinds of incorporeals – as is especially clear from the way in which the subjects ‘wholes and parts’, ‘motion’ and ‘coming-to-be and passing-away’ are grouped together as having to do with change, whereas we find them presented separately and relegated to different positions within the overall account in M 9 and 10.Footnote ³¹

Once again, we may presume that these differences are to be traced back to the different natures of the two works: a set of hupomnēmata on the one hand, and a more or less concise hupotupōsis on the other. Clearly, the latter genre implies a stronger degree of authorial intervention than the former. On the other hand, we may expect the former genre to offer a fuller range of materials at the micro-level, which in many cases is what M 9 and 10 in fact provide.

Sceptical strategies in the individual chapters

Also if one takes a look at the individual chapters of M 9 and 10, one is at first sight struck by the rather haphazard and non-uniform way in which these have been patched together, especially if one examines them against the background of the programmatic remarks offered in PH 1 on the Pyrrhonist's ‘method’.Footnote ³² On closer view, however, a more nuanced picture appears to emerge. On the one hand, Sextus' programmatic ‘instructions’ in PH 1 turn out to leave the Pyrrhonist with more freedom than the familiar ‘showcase’ examples of Pyrrhonism might seem to suggest. On the other hand, precisely by studying M 9 and 10 as a whole, as this volume allows us to do, we may be able to detect some underlying patterns and to clarify what goes on in one chapter by comparing it with what happens in others.

Let us first have a closer look at the way in which PH 1 characterizes the practice of Pyrrhonian scepticism:

This offers a clear general framework, and some further details provided by Sextus in his general account (katholou logos) of the nature of the ‘sceptic way of life’ (skeptikē agōgē) in PH 1 may help us to add a few finer shades. The first of these concerns the kinds of ‘things’ that may be selected to create the initial opposition. How is a Pyrrhonist supposed to construct his ‘opposed accounts’? First of all, they may indeed be contradictory. However, this need not be the case:

Secondly, as the above quotation from PH 1.8 has already suggested, the ‘opposed accounts’ may be either phenomenal or theoretical in character:

Thirdly, Sextus himself makes clear that we should not unduly focus on opposing arguments in any strict sense of the term:

If we now turn to the way in which the various sections of M 9 and 10 are structured, we may note, first, that opposed viewpoints do indeed constitute the core of the sceptical arguments set up by Sextus. Simple cases of conflicting appearances (the same tower appearing round from a distance and square from nearby, etc.) are of course not what we expect to find in a discussion devoted to what we might call the principia physica. Instead in most cases (god, cause, body, coming-to-be and passing-away) what we get is the opposition of things thought and other things thought. In two cases (where the existence of place and motion is at issue) the pro considerations can be seen either to articulate (place) or simply to represent (motion) the evidence of the phainomena, so that in these cases we are actually dealing with phainomena being opposed to nooumena.Footnote ³³ In two other cases (parts and wholes, time) the pro side is completely missing, so that we are not given an explicit opposition at all.

Secondly, in various chapters we find the opposition between contradictory theses (p or not-p) as an explicit organizing principle: thus the chapter on god first claims that ‘of those who have inquired into the reality of god, some say that there is a god, some that there is not, and some that there no more is than is not’ (M 9.50), and the ensuing discussion consists of arguments for the existence of the gods (M 9.60–136) followed by arguments against the existence of gods (M 9.137–8). A comparable structure can be found in the first part of the chapter on cause,Footnote ³⁴ and in the chapters on place and motion.Footnote ³⁵ Even in those cases (wholes and parts, time) where the positive part (i.e. material in support of the existence of x) is missing, the way in which matters are presented still suggests that what is at stake is the existence versus non-existence of the item at issue, as is clear from such conclusions as ‘it is left to say … that time does not exist’ (M 10.214) or ‘if so, it must be said that nothing is a whole; from which it follows that part does not exist either’ (M 9.357).

On the fact that such negative conclusions appear to be dogmatic, and as such at first sight unacceptable to a true Pyrrhonist, more will be said below. Here we may focus on another surprising aspect, namely the fact that they concern existence. Sextus' scepticism is often, and rightly, said to be essential rather than existential in nature. After all, it is the dogmatists' attempts to show us the real nature of things that constitute his primary target; he is not out to make us doubt the very existence of the external world. On closer view, however, the critical practice of M 9 and 10 appears to remain within the boundaries of Sextus' typical brand of essential scepticism. First, in most cases the critical arguments which we are offered do not take the form of straightforward arguments against the existence of x (where x stands for time, place, etc.) but of arguments serving to show that the dogmatists' attempts to define or explain the nature of x are all inconclusive. So, essential scepticism remains the backbone of the argumentative structure.Footnote ³⁶ Also, as we will see in the next section of this Introduction, the conclusion that ‘x does not exist’ should not be read in an absolute but in a qualified sense – as ‘x does not exist in the sense accorded to it by accounts just examined’ – so that no strong form of existential scepticism is implied. The reason why Sextus nevertheless sticks to the existential framing of his critical conclusions may well be that they are often supposed to be matched, whether explicitly or implicitly, by positive conclusions on the basis of enargeia on the other side of the balance: such considerations of enargeia usually do not concern the nature of x, but merely its existence, and that may well have determined the form of the counter-arguments as well.

Finally, Sextus' actual practice confirms the suggestion in PH 1 that the opposed ‘accounts’ need not be arguments. True, in these two books arguments, as assembled by the sceptics against the dogmatist positions, are basically what we are given on the negative side. These counter-arguments may sometimes go back to the interscholastic debates of the dogmatists themselves, but they are largely taken, we may suppose, from the arsenals of the earlier sceptical tradition (on which see below, pp. 30–2), although we cannot of course exclude the possibility that some of them are devised by Sextus himself. On the positive side, however, we may be given either arguments proper, or simply an appeal to enargeia, or the articulations of enargeia in the form of arguments or definitions, or a straightforward account or exposition of a theory (such as the Pythagorean account of number and its cosmological role in M 10.248–84).Footnote ³⁷ Sextus' choice for a specific type of account on the pro side will in each case no doubt owe something to the available evidence – we are dealing with the presentation of the case of the dogmatists. In addition, different subjects allow different types of accounts. In discussing the existence and nature of god, cause and number, it is perhaps less viable to point to enargeia than it is in the case of motion or place (or even time, where the existence seems obvious, but the attempt to determine its nature notoriously difficult), so that in the former cases arguments (god, cause) or an outline account (number) are rather what we expect to find, and what we do in fact find.

All this may be taken to indicate that, despite the difference in surface structure,Footnote ³⁸ the chapters of M 9 and 10 do appear to reveal a deep structure that seems to conform to the injunctions of PH 1. The use of existential language confirms that the issue is in general couched in the form of an opposition concerning the existence or non-existence of x, where x is one of the principia physica that together form the subject matter of Against the Physicists. The ‘accounts’ (logoi) that are being opposed can be arguments proper, but also theoretical accounts or definitions, or they may offer the enargeia of phainomena. On the pro side we may be given either ‘appearances’ (phainomena) or theoretical accounts, that is, ‘things thought’ (nooumena) by the dogmatists. On the contra side we have the defusing arguments of the sceptic (hence, also nooumena). Indeed, because the material on the pro side is already extant in the accounts of the dogmatists, we sometimes see Sextus arguing as if the sceptic's task is merely to provide the critical arguments on the contra side – or as he puts it at the beginning of Against the Physicists, to offer ‘a counter-argument against everything’ (M 9.3) – rather than to oppose the two accounts and thus induce suspension of judgment.Footnote ³⁹ However, the tension between these two perspectives is only apparent. In advocating suspension of belief, Sextus is describing the sceptic's eventual philosophical stance on a particular issue. In advocating ‘offering counter-arguments against everything’, he is describing the sceptic's procedure of producing the ‘opposed accounts’ by assembling the required critical material against the positive views of the dogmatists.Footnote ⁴⁰ It should perhaps not surprise us that the latter perspective is predominant in a text such as Against the Physicists, which, as we noted, should primarily be seen as a kind of storehouse of sceptical ammunition. One suspects, moreover, that it is also the latter conception of the primacy of the destructive task of the sceptic that is responsible for the occasional ‘elliptical’ way of presenting things, with the pro side missing or being present only implicitly (for example where the definitions attacked on the contra side may be taken to articulate some sort of enargeia on the pro side which is itself left unmentioned).

Of course invoking things that are implicitly present in a text has its dangers, and the above reconstruction does in fact require a modicum of charity, especially where Against the Physicists offers so few explicit clues on how the destructive side of the account needs to be read. As a result, the conclusions on the negative side (of the kind ‘that x does not exist’) often strike readers both as abrupt instances of non sequitur and as surprisingly negative for a Pyrrhonist, and it should be acknowledged that scholars have accordingly been tempted to look for different explanations from the one here offered, and to regard such conclusions as remnants of an earlier stage of Pyrrhonism or simply as an indication that Sextus' account is in some places a mess.Footnote ⁴¹ It may therefore be rewarding to have a closer look at the nature of the negative conclusions in Sextus.

Negative conclusions and suspension of judgment

In principle the problem appears to be clear. We may recall that the programmatic statement of PH 1.8 claims that the sceptic's ability to set up opposed accounts is an ability ‘by which, because of the equipollence of the opposed objects and accounts, we come first to suspension of judgment (epochē) and afterwards to tranquillity (ataraxia)’. As a matter of fact, however, the only section in M 9 and 10 to present a really neat example of the procedure of getting from opposed accounts directly to suspension of judgment is the section on god. In the sections on cause and body we get a conclusion which is at least very similar in that it refers to some sort of aporia (‘impasse’) or an ‘account which leads us nowhere’ (logos aporos).Footnote ⁴² But elsewhere, as we saw, we are presented with conclusions that may at first sight surprise, because they seem to go beyond suspension of judgment. At the end of the section on place, place is said to ‘have been done away with’. In the course of the discussion of time, it is more than once concluded that ‘time does not exist’ or that ‘time is nothing’.Footnote ⁴³ The section on number concludes that ‘number does not exist’ and the section on coming-to-be and passing-away concludes that ‘nothing comes to be or passes away’. At first sight these conclusions indeed smack of negative dogmatism, so that we may well ask whether they constitute the kinds of conclusions a Pyrrhonist is entitled to draw at all.Footnote ⁴⁴

It can be argued, however that Sextus' procedure is less crude than it might at first blush appear to be. First, a closer look at the way in which these apparently dogmatic conclusions are embedded within the overall argumentative context of the relevant chapters suggests that they should not be taken at face value. Thus the section on body concludes its elaborate investigation by claiming that (a) ‘if it [i.e. body] is neither sensible nor intelligible, and besides these there is no other alternative, one must declare that body is nothing (mēden einai to sōma)’ (9.439). But the text goes on to conclude that (b) ‘the account given of bodies has been shown by these arguments to lead us nowhere (ho peri tōn sōmatōn logos pephēnen aporos)’ (9.440). The suggestion is clearly that (b) should be read as a qualification of (a): body turns out to be nothing in so far as we follow the available theories (‘the account given of bodies’) about it, for these theories lead us nowhere. This still leaves open the possibility that the final conclusion will be that we have other (unstated) arguments in favour of the existence of bodies (e.g. the evidence of the senses, or enargeia), so that we end up with suspension of judgment after all. In other words, it is very well possible to read this section as offering a sketchy and elliptical version of the proper Pyrrhonian procedure, one that concentrates on the arguments contra the dogmatic views.

Such a reconstruction seems to gain support from the section on motion where the claim ‘there is no motion’ (M 10.168) is followed by the claim that we should hence suspend judgment, ‘because of the equipollence of the sense-evidence (enargeia) and of the arguments which contradict it’ (M 10.168).Footnote ⁴⁵ So here the claim ‘there is no motion’ is not a final conclusion in a spirit of negative dogmatism but represents one side of the sceptical balance, a conclusion that is valid only in so far as the arguments are concerned. The section on place seems to point in the same direction, for there Sextus initially describes his procedure as aiming at suspension of judgment (M 10.6), whereas he concludes his account (M 10.36) by claiming that ‘we have abolished place’. Clearly these two claims are intended to be compatible.Footnote ⁴⁶ Also elsewhere in Sextus we find examples of this Nebeneinander of the language of suspension and equipollence on the one hand, and conclusions to the non-existence of a particular object or skill on the other.Footnote ⁴⁷

It has been argued that such intimations of negative dogmatism are due to Sextus' sources and that these sources represent an earlier phase of Pyrrhonism, of which we also find traces in the account provided by Diogenes Laertius 9, which apparently condoned such one-sided negative conclusions.Footnote ⁴⁸ This may well be true, as it may also be true that we can detect a difference here between M and PH, and that the latter work is in general more careful in explicitly opposing the arguments which lead us to conclude that x does not exist to other considerations (usually linked with enargeia or the evidence of sensation or common sense) which draw us in the opposite direction. In such cases it is more immediately evident that statements of the kind ‘x does not exist’ are only apparently instances of negative dogmatism, and that the claim that x does not exist is equivalent to saying that the ‘physical theory of the dogmatists about it is inconceivable’ (PH 3.62) or that x is inapprehensible (akatalēpton), or unthinkable (anepinoēton) or impossible (adunaton) on that theory.

It is far from clear, however, how significant these differences between PH and M are. First of all, we have just seen that there are a number of indications that the Sextus of M 9 and 10 believed the relevant passages to be compatible with other passages which more clearly represent his own preferred brand of Pyrrhonism (including suspension of judgment as a conclusion), and there is nothing to indicate that he was at any point in any strong sense committed to a form of negative dogmatic conclusions. Secondly, even in PH we find cases where the positive half of the diptych, so to speak, is missing.Footnote ⁴⁹ This means that the differences in this respect between PH and M seem to be gradual rather than radical.Footnote ⁵⁰And even if we admit that the composition of M is in general less achieved in so far as it contains a larger number of such ‘elliptical’ presentations, it is not clear that this should be ascribed to a development in Sextus' style of thinking. They may also be due to the different nature of the two works. After all, also on the assumption that the passages suggesting some form of negative dogmatism will be mainly due to his scissors-and-paste copying from earlier Pyrrhonian sources, we are more likely to find them in M, which is more of a storehouse of sceptical arguments, than in PH, which in general shows a higher degree of authorial intervention.

Finally, a general point about the use of phrases that may seem to indicate a commitment to negative dogmatism may be in order here. In PH 1.187–209 Sextus famously discusses a number of sceptic expressions and formulae and the way in which they should and should not be taken. Among them are expressions which at first sight may appear to be dogmatic in character, such as ‘all things are undetermined’ (1.198–9). ‘All things’ should here be read, we are told, as ‘such of the non-evident things investigated by the dogmatist as I have examined’ and ‘are’ should be read as ‘appear to me’. At PH 1.206 he claims that the list of expressions he has just given is not exhaustive and that ‘it is possible to explain the rest by deduction from the foregoing’. We may then perhaps assume – and it certainly would seem to fit in with the interpretation just given – that a conclusion like ‘time does not exist’ is, at least in the context of the sceptic's dialectical investigation, meant to be taken as ‘time in so far as it has been investigated by the dogmatists whose views I have examined appears to me not to exist’, thus conveying something that at a certain point (as the conclusion of his dialectical investigation) appears to the sceptic, an appearance to which either immediately or at some later point a conflicting appearance (for example one conveying the enargeia of time) may be opposed, which will then induce the sceptic's suspension of judgment. The conclusion can thus be read as (implicitly) provisional and qualified and need not straightforwardly be taken as an instance of negative dogmatism. Rather than something that goes beyond suspension of judgment, it may be regarded as part of the procedure that leads up to it.

Types of arguments

The critical arguments Sextus offers on the contra side basically come in two types. He sometimes refers to the first type as ‘primary in order’ (prohēgoumenon or prohēgoumenōs),Footnote ⁵¹ but in some contexts they can also be labelled as ‘more general’, in the sense of applying not to any particular conception of cause, place, time, and so on, but to any conception of it (PH 3.134; M 9.258).Footnote ⁵² These arguments have a recognizably dilemmatic structure, discussing, for example, the main properties of time directly in one complex argument (‘if time exists, it is either a or b, but if it is a, it must be either x or y, etc.’), where the variables a, b, x, y, etc. stand for pairs of mutually exclusive general properties such as ‘corporeal’, ‘incorporeal’, ‘extended’, ‘unextended’. These arguments then show that each time both horns of the dilemma (i.e. both opposite characteristics a, b or x, y) are ruled out, and as a result the antecedent of the conditional (e.g. ‘time exists’) is ruled out as well. Sometimes Sextus (or his Pyrrhonist source) adds in an extra element of parsimony by tarring two dogmatic concepts with the same general brush, for example where he eliminates both the active and the passive principles by eliminating the concept of touch by which they are connected.Footnote ⁵³ To a modern reader, and perhaps also to an ancient reader, these ‘primary’ arguments may often seem boring and mechanical, but they do have a certain persuasive force conveyed by their apparent exhaustiveness. This may well be why Sextus at one point refers to this type of argument as ‘deducing the point at issue in a powerful way’.Footnote ⁵⁴

The other main type of argument proceeds in a more properly dialectical way in taking the tenets and arguments of specific dogmatic philosophers as their starting point. In the section on place in PH 3 this type of argument is distinguished from the more general (‘primary’) ones as ‘more varied’ (poikilōteron).Footnote ⁵⁵ These ‘more varied’ arguments may at first sight seem structurally similar to the ‘primary’ arguments, for they may be reconstructed as starting from such premises as ‘if time exists, it is either a or b or c, etc.’ However, a, b, c, etc. now no longer stand for a supposedly exhaustive list of mutually exclusive properties, but for definitions offered by individual philosophers. As a rule the first premise of the underlying hypothetical syllogism is not stated explicitly, whereas there is no guarantee that the list of options discussed is indeed exhaustive. As a consequence, such arguments are strictly speaking neither valid nor sound.Footnote ⁵⁶ But here we should recall that Sextus' exposition on the vocabulary used by the Pyrrhonists in PH 1 specifies that apparently unqualified negative conclusions (such as ‘all things are undetermined’) should in fact always be taken with the rider that the conclusions apply only to ‘such of the non-evident matters investigated by the dogmatists as the sceptic has in fact examined’ (PH 1.198). As we saw, this means that a conclusion like ‘time does not exist’ in the context of Sextus' work may be taken to mean: ‘it does not exist in the sense stipulated by the theories we have examined’. At a more general level we may perhaps add that a Pyrrhonian conclusion is always provisional: the sceptic will go on searching and he never as a matter of principle excludes the possibility that other and better theories can be found or may come up.Footnote ⁵⁷ In the meantime, such negative conclusions as may result from his dialectical investigations, however provisional, may still have a certain persuasive force: if the best philosophers are unable to come up with an unproblematic definition of, say, time, we are perhaps entitled to conclude that we should at least for the moment despair of finding such a thing.

At the same time, all this may serve to show that the persuasive force of the sceptic's negative arguments may differ considerably. In this connection we may recall that Sextus himself refers to the other type of argument (the ‘primary’ arguments) as ‘powerful’.Footnote ⁵⁸ We may perhaps infer that he (rightly) thought of these ‘more varied’ dialectical arguments as less forceful by themselves. Perhaps we may even connect these kinds of difference in persuasive force with the notorious claim, made in PH 3.280–1, that the sceptic will use arguments of various strengths, according to whether his opponents are more or less affected by the disease of dogmatism.Footnote ⁵⁹ In that case we need not take the latter claim to refer to the ‘indiscriminate use of good and bad arguments’, nor as implying that ‘scepticism as a therapeutical procedure takes advantage of any means in order to liberate people from the burden of their own fixed, intolerant and a-critical beliefs’.Footnote ⁶⁰ It may simply mean that in many circumstances, and for all practical purposes, the less rigid procedure of dialectically defusing the available dogmatic positions – or even a well-chosen subclass of the available dogmatic positions – will be sufficient to induce suspension of judgment. After all, suspension of judgment does not appear to be something we logically conclude to, but it is rather a condition which is, so to speak, supervenient on the investigation we have been undertaking.Footnote ⁶¹ Anyway, it is the fact that Sextus' procedure often seems to be incomplete – not all relevant theories may be reviewed, not every argument is successfully countered – that sometimes induces modern readers to think of it as psychological or even rhetorical (in the sense of aiming at persuasion), rather than properly philosophical (in the sense of aiming at sound conclusions) in nature.Footnote ⁶²

The scope of Sextus' scepticism

So much for the question of to what extent Against the Physicists displays Sextus' general strategy of opposing accounts and to what extent the conclusions he draws can be understood and accepted from the general point of view of Pyrrhonism. Another question which has received quite some attention in the scholarly literature concerns the scope of Sextus' scepticism: does the practice of setting up opposing accounts leading to suspension of judgment apply to each and every subject? Ordinary life certainly demands that we entertain views about many things which we may use as a standard of action. Sextus explicitly makes room for such views in the everyday context of what he calls the ‘conduct of life’ (biōtikē tērēsis) of the sceptic:

So in order to get along in ordinary life the sceptic will entertain some non-committal (he is said to hold them ‘undogmatically’) views in these four areas. Can such views count as beliefs of some sort? And if so, how do they differ from the kinds of belief the sceptic is not supposed to have, in areas where his attitude is supposed to be the attitude of creating opposing accounts and suspending judgment? Is the difference one between various classes of objects (e.g. the demands of ‘ordinary life’ versus the objects of ‘science’ or ‘philosophy’)? Or are we rather dealing with different epistemological stances (different kinds or levels of belief) towards the same objects or questions (e.g. non-committal beliefs versus theoretically argued beliefs)? The debate about these issues, and about how we should as a consequence envisage the differences between ancient and modern scepticism, has been complicated and wide-ranging, and there is no need to trace its intricacies in the context of this introduction.Footnote ⁶³ Nor is it to be expected that this volume, or the text of Against the Physicists will give definitive answers to the relevant philosophical questions. Nevertheless the text does contain some examples that should be taken into account by anyone discussing the scope of Sextus' scepticism, and some of the relevant questions accordingly crop up in some of the contributions to this volume.

Thus, we encounter various examples of ways in which a sceptic can go along with the enargeia of particular phenomena, without any strong form of epistemic commitment.Footnote ⁶⁴ Thus, the chapter on motion suggests that although a Pyrrhonist at the theoretical level suspends judgment on the otherwise evident phenomenon of motion, because its very evidence is counterbalanced by theoretical considerations showing that any attempt to define motion fails, he may for everyday purposes follow this evidence without any theoretical commitment as a matter of following ‘life’ (bios), which in this case means, in the words of PH 1.23 (quoted above): the ‘guidance of nature’.Footnote ⁶⁵ We may perhaps connect this difference with what Sextus elsewhere has to say about the sense in which the sceptic does and does not have a ‘doctrine’ or ‘doctrinal rule’ (hairesis). A sceptic does not have a doctrine, he claims, if by this we mean ‘adherence to a number of dogmas which are dependent both on one another and on appearances’ (PH 1.16–17). But, he adds in the same context, ‘we do follow a line of reasoning which, in accordance with appearances, points to a life conformable to the customs of our country and its laws and institutions, and to our own feelings (pathē)’. This suggests a particular way in which a Pyrrhonist may accept the enargeia of appearances: he may do so as long as he refrains from integrating them in any broader web of beliefs, that is, he should, on the one hand, not support the evidence of enargeia with arguments, nor should he, on the other, use this enargeia itself as a basis for any kind of further inference or theorizing. This, apparently, is what his non-committal (adoxastōs) way of following appearances should amount to.

In the chapter on place Sextus puts some additional flesh on the bones of the relevant distinction by arguing that there is a ‘broad’ and non-technical use of the concept of place – as in ‘Socrates is in Athens’ – that is acceptable for the sceptic, precisely because, and in so far as, it is uncontroversial (homologon); as such, we may add, it need not be defended by any form of argument.Footnote ⁶⁶ So here again we may follow ‘life’ without making any theoretical presuppositions. As soon, however, as we try to translate this ‘broad’ conception of place into a more precisely circumscribed conception, the sceptic machinery of constructing opposing accounts and inducing suspension of judgment inevitably starts doing its critical work.

It is from this same perspective, presumably, that we should also interpret what is being said about the conception of god. The chapter on god in Against the Physicists offers us an instance of what PH 1.23 labels following ‘tradition of customs and laws’. That is: although Sextus naturally advocates suspension of judgment about theoretical accounts of the existence and nature of the gods, he at the same time enjoins us to go along with everyday religious practice. Whether this in the end amounts to a coherent position is controversial. On the one hand, it may be argued that even the cult-oriented religions of the Greeks and Romans involved some beliefs about the existence, origin, nature and behaviour of the gods, and it is not immediately clear why these beliefs would be less vulnerable to the critical procedure of creating opposite accounts resulting in suspension of judgment than the theological beliefs of the dogmatic philosophers. Indeed, in the same context (M 9.192) Sextus himself does in fact describe the religious views of ordinary people as mutually opposing and as such inducing suspension of judgment.Footnote ⁶⁷

On the other hand, the analogy with the cases of motion and place – or indeed with the way in which the Pyrrhonist can say non-committally (adoxastōs) that ‘honey is (i.e. appears to me) sweet’ – may offer some help. The idea may well be that the sceptic's ‘going along’ with the tradition (presumably what is meant here is: a tradition, i.e. his own particular tradition) is in a similar way non-committal. In other words, the Sextan sceptic does not thereby necessarily accept this tradition in the same way as do ordinary religious ‘believers’, who may well have views about what these gods really are, or supposed evidence for their existence (for example the way in which they supposedly have reacted to prayers or sacrifices), or reasons to assume that their gods are superior to the gods of other civilizations. Instead, he will adopt a more non-committal stance with a pretty minimal commitment.Footnote ⁶⁸ This appears to be a coherent position, although we may have some doubts whether it is a viable one in practice. Perhaps it is supposed to work only in so far as and as long as the tradition itself remains uncontroversial (compare the case of the conception of ‘broad’ place). As soon as it is challenged by ordinary believers who have stronger views than the sceptic himself, or by dissenters within the tradition, or by a different tradition, or by the theology of the philosophers, the sceptic may well have to suspend judgment on the relevant point after all. But perhaps the actual circumstances in the ancient world – one may think of the cult-oriented nature of Graeco-Roman religion and its relative openness to new gods or cults – made it easier to adopt the stand advocated by Sextus.

Examples such as these may serve to show that, even if there remains room for discussion on various details surrounding the question of the scope of Sextan scepticism, the case studies from M 9 and which this volume offers may at least contribute to the further articulation of the terms of the general debate, which has thus far, for obvious reasons, mainly been based on the more theoretical ‘general account’ of PH 1. In this connection their study should of course be combined with relevant parallel evidence on the attitude recommended by Sextus in the areas of logic and ethics. Thus, in line with what he has to say about the extent to which the sceptic has or does not have a ‘doctrine’ (see above), he recommends that the sceptic accepts the enargeia of phenomena for the purposes of everyday life, but not in the same way as it is accepted by the dogmatists, namely as indicating how matters really are,Footnote ⁶⁹ or as a basis for sign inference about the non-evident.Footnote ⁷⁰ As noted earlier, one should be careful not to embed the enargeia as such in any larger network of beliefs. Also the kind of Pyrrhonist ethics advocated by Sextus appears to be a matter of following conventional appearances of value, without any strong concern about them, and without any attempt to show that they are well founded.Footnote ⁷¹ Finally, these examples should also be connected with the evidence forthcoming from M 1–6, the books attacking the liberal arts, where we find Sextus working along similar lines and condoning those types of technē that do not require theory but only experience, such as agricultural astro-meteorology (the art of detecting weather signs), basic grammar (simple writing and reading skills), and music in the sense of the art of playing an instrument.Footnote ⁷²

Sextus and his sources

About Sextus' sources it is impossible to be very specific. He himself tells us that he uses material ‘from the sceptical tradition’ (ta apo tēs skepseōs, see e.g. M 10.20). Correspondences between passages in Sextus and passages in Diogenes Laertius 9.74–108 (Diogenes' discussion of Pyrrhonian philosophy) have long been noticed by scholars. It is chronologically unlikely that Sextus used Diogenes (the reference in Diogenes 9.116 to Sextus and his pupil Saturninus hardly suggests that Sextus was a contemporary). Apart from this, the possibility that either of the two texts was the source of the other one may be excluded, for there are too many differences between the two accounts. The conclusion must be that they are both relying on an earlier source or sources, either directly or at one or more removes, and it is only natural to assume that these sources will have been predominantly of a Pyrrhonian bent.Footnote ⁷³ This goes not only for the ‘general account’, that is, the systematic description of Pyrrhonian philosophy (including the description of the famous ‘tropes’), but also for the ‘special account’ dealing with individual concepts, arguments and theories espoused by the dogmatists. Apparently Pyrrhonist collections of arguments were available, and we may presume that these also used earlier collections compiled by Academic sceptics. This helps to explain, for example, that the chapter concerning god in M 9 to a large extent reflects the theological debate between Stoics and Academics, including a distinction which is being made between the question of the origins of our conception of god on the one hand, and the question as to the existence of god or gods on the other.Footnote ⁷⁴ Sextus appears to be dependent on non-sceptical sources, such as doxographies, as well, although such materials may also have reached him through the intermediate stage of the sceptical tradition, and we cannot exclude the possibility that he also made his own excerpts of some important primary sources. In short, there is a lot here that we do not know.

The question of Sextus' originality is a typically modern one. No doubt what Sextus apparently wanted to offer in his Against the Physicists was a maximally comprehensive, helpful, clear and persuasive overview of the relevant physical main tenets of the dogmatists plus the critical counterpart to these tenets which a Pyrrhonist could devise. It is only natural that such an enterprise leaned heavily on existing sources, especially on extant collections of sceptical arguments or doxographical overviews and summaries. How did he deal with these pre-existent materials? As we noted, there are quite a number of parallels between the texts of M 9–10 and those of PH 3, but also between M 9–10 and the later work against the liberal arts, which is now known as M 1–6.Footnote ⁷⁵ In some cases these parallels may be taken to suggest that he copied his own earlier work in a later context, in others that he used a common source twice, or that he used two different sources which were both indebted to the same source or tradition. In all cases the parallels suggest that he did not greatly alter the form and content of his examples, but that he did leave himself room for variation: to add or delete materials, or to abridge or tidy up his materials in various modest ways.Footnote ⁷⁶ In general, as we noted, we appear to witness a higher degree of authorial intervention in PH than in M, and, as we also noted, there remains a kind of tension between his attempts to create or suggest an overall framework for the argument of Against the Physicists and the actual contents of what he (following his sources) has to offer. So in Against the Physicists the degree of authorial intervention appears to be more limited. At the same time he comes across as someone who has a clear grasp of the nature of his Pyrrhonist project, in M no less than in the more systematic first book of PH. We are not dealing with a mere scissors-and-paste man. In fact, as Richard Bett has argued, in reading Sextus one does get the impression of dealing with one and the same authorial personality.Footnote ⁷⁷

If this is the general picture, which inevitably remains rather vague, a few further observations may help to add some detail. First, it appears that, whatever sources Sextus may have used, they were on the whole relatively up to date: much of what he offers in these two books on physics reflects the philosophical situation in the late Hellenistic and early Imperial periods – roughly the first century bc and the first century ad – where Aristotelian physics had been ‘re-discovered’, but where for the rest Stoicism and Epicureanism were the most prominent philosophical schools, in particular in so far as physics is concerned.Footnote ⁷⁸ The Platonic contribution to cosmology and physics had been much less prominent, but Sextus' chapter on number may well reflect Neopythagorean preoccupations which blossomed in the same period.Footnote ⁷⁹

Secondly, that Sextus, or his source, made ample use of available summaries or doxographies is not just a reasonable guess but can be substantiated with evidence. Thus, we find numerous references to Aristotelian physics (especially on the subjects of place, time and motion),Footnote ⁸⁰ which in itself shows that the revival of Aristotelianism from the first century bc onwards left its traces in the Pyrrhonist tradition. However, in at least one (place), it can be shown that Sextus or his source did not have the actual text of Aristotle (i.e. Physics 4) before him but used a summary of the kind offered by the likes of Arius Didymus or Nicolaus of Damascus.Footnote ⁸¹ There are also indications of the pervasive influence of the placita literature. The doxography offered at the outset of the chapter on body is paralleled by the Aëtian doxography in Ps.-Galen, and the Stoic definitions of place in M 10.3 are partly paralleled by similar sets of definitions in Aëtius and Arius Didymus. Of course there will be other cases where we do not have any parallel evidence at our disposal and where the provenance will thus remain obscure. Anyway, this broad use of summaries and doxographies need not surprise us, given the working methods of many ancient philosophers in general, and given the enormous range of materials which such sceptical overviews as Sextus' Skeptika Hupomnēmata (but also its possible Pyrrhonian sources) were supposed to cover. But it remains salutary for those modern readers who mainly consult Sextus as a source on earlier philosophies to realize that much if not most of what he offers is both derivative and abridged.