Most of the texts discussed in the previous chapter remained unknown to the West during the Middle Ages. It is not surprising that the magical papyri, Hermetica, and works of Iamblichus and Proclus went untranslated; rather more surprising is that the same is true of the works of Justin Martyr, Athenagoras, Clement, Origen, and Athanasius, with the exception of Origen's De Principiis and some exegetical treatises. All told, of the works we have discussed the only one that played a role in the formative stages of western thought was the New Testament, which of course was available in the Vulgate of Jerome. There we find energeia translated as operatio and energein as operari. Although these renderings were probably the best available, they do not possess the same fluidity of meaning as the original. To think of the divine operationes as forces or active powers that can be shared in by human activity would not normally occur to a Latin reader. This is not only because the major works in which the expansion of meaning took place were not translated into Latin; it is also because operatio does not share the association of energeia with actuality, much less with the fusion of activity and actuality that we have traced in earlier chapters. That is why, when the works of Aristotle were translated in the twelfth and thirteenth centuries, energeia had to be rendered in different contexts by three different terms: operatio, actus, and actualitas.

Up to this point we have traced two broad strands in the development of Aristotle's thought on energeia. Both take their beginning from his early use of the term to mean the active exercise of a capacity as distinct from mere possession of that capacity. In one strand we find Aristotle purifying energeia from its early associations with motion or change (κίνησις), distinguishing it as that type of activity that contains its own end and hence is not constrained to unfold through a temporal process. The other strand is rooted in the early distinction between energeia and dunamis in the sense of capacity. As Aristotle broadens dunamis to encompass all types of potency, he correspondingly broadens energeia to encompass all types of actuality. As we have seen, he goes on to argue that actuality is prior to potentiality in a number of respects, of which the most important is priority in substance. His argument for this latter claim hinges on the view that things existing eternally and of necessity, such as the stars and planets, are free of potency in respect to existence. There is thus an intimate link between eternity and necessity, on the one hand, and actuality on the other.

That link becomes a central theme of Metaphysicsxii.6–10, Aristotle's only sustained discussion of the Prime Mover.

In his commentary on Aristotle's de Interpretatione Ammonius asks ‘among which of the things that are in any way one should look for truth and falsehood’ (17, 29–30). In Aristotle's works there is no formulation of this or of an equivalent question. So, there is a case for doubting that Aristotle ever addressed the problem of what items are bearers of truth or falsehood. However, even if Aristotle never addressed this problem, it is still worthwhile considering what the items are which Aristotle does in fact speak of as true or false. For this result will provide a useful indication for determining what solution Aristotle would have offered for the problem of what items are bearers of truth or falsehood, had he addressed it.

Aristotle applies the word ‘true’ (‘ἀληθής’) and its cognates to items of three main kinds: objects (which include states of affairs), mental items (states or acts of believing, knowing, grasping by means of the intellect, perceiving, imagining, etc.), and linguistic items (sentences).

Section 1 of this chapter focuses on objects, in particular on states of affairs. I examine two passages from the Metaphysics. The first, which constitutes the beginning of Δ 29, is the most unequivocal testimony of Aristotle's commitment to states of affairs (I devote some arguments to showing that it is really states of affairs Aristotle is concerned with). The second Metaphysics passage is the first part of Θ 10. Aristotle describes states of affairs as being true or false in the strictest, i.e. most fundamental, sense because their truth and falsehood is appealed to in explaining the truth and falsehood of items of other types: an affirmative predicative belief or sentence is true (false) when and only when the state of affairs it concerns is true (false), while a negative predicative belief or sentence is true (false) when and only when the state of affairs it concerns is false (true).

The two-place relations involved in the truth conditions for quantified assertions. An important feature of [17], the definition of truth for predicative assertions I attribute to Aristotle, is that the truth conditions for (those utterances which are) quantified predicative assertions involve two-place relations (the combination of universally holding, the division of universally failing to hold, the combination of not universally failing to hold, and the division of not universally holding) obtaining between the universals signified by the predicates and the subjects of the assertions. These two-place relations are to some extent reflected in views formulated in the logical writings of Aristotle himself and of some of his pupils.

1. The expression ‘to hold universally’. In some passages Aristotle uses the expression ‘to hold universally’ (‘καθόλου ὑπάρχειν’) to express a relation which is at least close to the combination of universally holding. This fits well with the part of [17] which concerns universal affirmative predicative assertions.

2. Universal affirmative predicative assertions and being a part of a whole. At the beginning of the Prior Analytics Aristotle says that he intends to determine ‘what it is for this to be, or not to be, in this taken as a whole [ἐν ὅλῳ εἶναι ἢ μὴ εἶναι τόδ∊ τῷδε]’ (1.1, 24a13–14). Aristotle probably wants to describe what universal affirmations and denials say.

This chapter examines what truth conditions for predicative assertions Aristotle is committed to.

Section 1 addresses a preliminary issue: Aristotle's conception of universals. Universals are neither concepts nor linguistic expressions: rather, universals are objects whose nature is neither mental nor linguistic. A universal is an object which is predicated of many things, an individual is an object which is not predicated of many things.

Sections 2–4 concentrate on the truth conditions for singular and quantified predicative assertions (evidence is mainly provided by passages from de Interpretatione). Section 2 addresses the discussion of truth and falsehood in de Interpretatione 1, where Aristotle alludes to the theory of Metaphysics Ε 4: in an affirmative (negative) predicative belief one object is joined with (separated from) one object. The bulk of section 2 is taken up by a discussion of two objections that could be raised against connecting de Interpretatione 1 with Metaphysics Ε 4. Section 3 addresses Aristotle's theory of assertions. Not every sentence is true or false (prayers are neither), and every sentence that is true or false is an assertion (the converse fails). Every affirmative predicative assertion asserts something ‘about’ something, every negative predicative assertion asserts something ‘away from’ something. The operation of asserting-about (asserting-away-from) performed by an affirmative (negative) predicative assertion is the linguistic counterpart of the operation of joining (separating) performed in an affirmative (negative) predicative belief. In both cases the operations are performed on objects (not on linguistic expressions or on thoughts).

Is Aristotle coherent? Aristotle's position in Int. 9 has been taken to be incoherent. For Aristotle accepts Excluded Middle (which involves endorsing every instance of ‘α ∨ ¬α’) but denies Bivalence (which involves denying that at every time every assertion is either true or false). It is hard to see how this could be coherent – but the following formal semantic theory shows that it is.

Expanded semantic theory Appendix 5 contained a formal presentation of a semantic theory for a fragment of natural language that includes some present-tense predicative assertions. Here, in appendix 6, this semantic theory is expanded. The expanded semantic theory covers a slightly larger fragment of natural language, a fragment including not only some present-tense predicative assertions, but also some past- and future-tense predicative assertions, some ‘tomorrow’-assertions (i.e. predicative assertions that begin with an utterance of the phrase ‘tomorrow it will be the case that’), and some negative and disjunctive assertions.

Expansion of the alphabet The alphabet of the semantic theory presented in appendix 5, described in [54] and [55], must be expanded.

Can Aristotle's theory of truth for assertions be regarded as a correspondence theory of truth? Section 1 argues that on certain conceptions of truth as correspondence it cannot, but on at least one other it can. Specifically, Aristotle's theory of truth can be regarded as a correspondence theory of truth in that it can be regarded as taking the truth of an assertion to amount to a relation of isomorphism to reality. In particular: it relies on a classification of assertions, with each class it associates some characteristic that can hold of the items an assertion is about, and it claims that an assertion is true when and only when the characteristic associated with its class holds of the items it is about.

Section 2 addresses Aristotle's reaction to the Liar, which creates a puzzle for correspondence theories of truth like Aristotle's. It is not clear whether Aristotle addressed the Liar, and, in case he did, what version of it he confronted. On the somewhat optimistic assumption that he did address a robust version of the paradox, his solution is that the assertion on which the paradox turns (an utterance of the sentence-type ‘I am speaking falsely’) is sometimes neither true nor false.

A CORRESPONDENCE THEORY OF TRUTH?

Focusing on truth for assertions. The theory of truth we are in the best position to attribute to Aristotle is a theory of truth for assertions (utterances) (it was described in chapters 2 and 3).

In chapter 9 of de Interpretatione (henceforth ‘Int. 9’) Aristotle claims that some future-tense singular assertions are sometimes neither true nor false, and therefore refute Bivalence, the principle stating that every assertion is always either true or false. Aristotle's argument goes as follows:

Int. 9 divides into four parts: the first (18a28–33) is introductory (it briefly states Aristotle's position); the second (18a34–18b25) contains two arguments from Bivalence to Determinism; the third (18b26–19a22) argues that Determinism is absurd; the fourth (19a23–19b4) contains Aristotle's solution to the problems raised by Bivalence and Determinism.

In section 1 of the present chapter I present the most important modal attributes and theses at play in Int. 9: the attribute of necessity as ineluctability (a diachronic modality, with two ‘slots for dates’), the thesis of the necessity of the present and the past (the thesis that for whatever obtains at any time it is both then and later necessary to obtain then), and Determinism (the thesis that for whatever obtains at any time it is always antecedently necessary to obtain then). Aristotle endorses the necessity of the present and the past, but rejects Determinism.

The study of truth is a central part of the philosophical tradition we have inherited from classical Greece. Aristotle played an important role in developing and sharpening the debate in this area and on many issues that are connected with it. I have two primary goals: to offer a precise reconstruction of all of Aristotle’s most significant views on truth and falsehood and to gain a philosophical understanding of them. In this introduction I first offer an overview of Aristotle’s theory of truth and then discuss the methodology I adopt in pursuing my primary goals.

AN OVERVIEW OF ARISTOTLE’S THEORY OF TRUTH

Why an overview? Aristotle speaks about truth and falsehood in passages from several works, mainly the Categories (chapters 4, 5, 10, and 12), de Interpretatione (chapters 1–9), Sophistici Elenchi (chapter 25), de Anima (chapter 3.6), and the Metaphysics (chapters Γ 7, Δ 7, Δ 29, Ε 4, and Θ 10). Truth and falsehood are not the main topic of these works: their discussions of truth and falsehood are asides. Reconstructing an Aristotelian theory of truth and falsehood on the basis of such asides poses complicated problems of various sorts. To help readers to keep their orientation through the many bifurcations of the arguments addressing these problems, I decided to offer a concise but precise map of the territory – an overview of Aristotle’s theory of truth.

The evidence. At 1051b2–3 various readings are available. E and J have

1. τοῦτο δ'ἐπὶ τῶν πραγμάτων ἐστὶ τὸ συγκ∊ῖσθαι ἢ διῃρῆσθαι.

This reading, also presupposed by William of Moerbeke's translation, is printed by some early editors (the Aldine edition, Brandis, and Weise).

Ab has instead

1. τοῦτο δὴ ἔτι τῶν πραγμάτων ἐστὶ τῷ συγκεῖσθαι ἢ διῃρῆσθαι.

No editor prints this.

Most modern editors (Bekker, Schwegler, Bonitz, Dübner, Christ, Ross, Tredennick, and Jaeger) print

1. τοῦτο δ' ἐπὶ τῶν πραγμάτων ἐστὶ τῷ συγκ∊ῖσθαι ἢ διῃρῆσθαι, a text obtained by combining readings [a] and [b].

Evaluation. Reading [b] makes no sense and must be discarded. Reading [a] has the edge on [c] because of the parallel with 1051b11–13, 1051b19–20, and 1051b33–5. I therefore opt for reading [a].

In chapter 2 I sketched a theory of the truth conditions for predicative assertions which can be plausibly attributed to Aristotle. The goal of the present chapter is to attain the corresponding result for existential assertions: to outline a theory of the truth conditions for existential assertions which captures Aristotle's views concerning this subject. Aristotle concentrates on existential beliefs and assertions of two types: those concerning simple items, which are essences and incorporeal substances (i.e. God and, perhaps, the intellects that move the heavenly spheres), and those concerning material substances.

The first two sections of the chapter focus on existential beliefs and assertions concerning simple items. The main witnesses are the middle part of Metaphysics Θ 10 and the beginning and the end of de Anima 3.6. Section 1 offers truth conditions for existential beliefs and assertions concerning simple items. Simple items are essences and incorporeal substances, all of which are everlasting, i.e. exist always. It follows that every existential affirmative belief, or assertion, concerning a simple item is always true, and every existential negative belief, or assertion, concerning a simple item is always false. Section 2 addresses a scholarly issue: what does Aristotle have in mind when in Metaphysics Θ 10 he speaks of ‘non-composite substances’? I defend the traditional interpretation, according to which Aristotle has incorporeal substances in mind.

Section 3 addresses the truth conditions for existential beliefs and assertions concerning material substances.