In outlining the history of the discipline, I have already indicated a number of ways in which specific theories and concepts provoked philosophical responses from the mechanical theorists themselves. I shall now consider evidence from ancient Greek natural philosophers – including philosophically inclined medical theorists – concerning the reception of ideas from mechanics.

On a number of specific issues, natural philosophers engaged with the implications of mechanical theory and took seriously the question of its relationship to natural philosophy. There is, moreover, some evidence of a commitment, in a few ancient thinkers, to the use of mechanics as a heuristic. There are reports in late antiquity of those who considered whether the natural world might be understood to ‘work like that’: to function in ways that could be illuminated by appeal to the working artifacts that were available at the time. This latter evidence tends to cluster in three areas: the functioning of organisms, the motion of the heavenly bodies, and – at a more general level – the operation of causality in nature as a whole in relation to a directing intelligence.

The existence of complex working artifacts exhibiting regular, pre-programmed causal sequences in their operation showed vividly what could be achieved by material arrangement alone. This, in turn, threatened some of the classic arguments for teleological explanations, which are typically based on the impossibility of adequate explanation of the phenomena using the resources of materialism alone.

It is a commonplace that the Hellenistic period was a time of great productivity in the sciences. The patronage of the court of the Ptolemies made Alexandria in particular a centre for work in many fields, including medicine, mathematics, mechanics and astronomy. Many scientific and philosophical texts from the period are lost or survive only in part; the dates of many key figures are unknown. Nonetheless, there is evidence of much work in mechanics – theory and practice – in the post-Aristotelian period. Some texts have survived that attempt to unify, analyse and explain the techniques of mechanics. There are reports of devices involving valves, pistons and pumps, water-lifting screws, water organs, catapults, steam devices, pneumatic toys and display pieces, theatrical automata and planetary models. Archaeological finds have also yielded some physical evidence of the technology available and indicate that the sophistication of the technology exceeds that described in the surviving literary evidence. Despite much uncertainty and questionable evidence, it is clear that engineering advanced considerably, particularly during the Hellenistic period; there were also attempts to develop theories to explain the operation of mechanical devices.

There is some uncertainty about the extent to which scientific ideas filtered through to the Athenian philosophical schools during the Hellenistic period. Athens continued to be the philosophical centre for more than two centuries following Aristotle's death, spatially separated from the major hub of the natural sciences in Egypt. Philosophers during this period seem to have increasingly turned away from natural philosophy to other topics.

In this chapter I consider issues that form an essential background to the question how the development of ancient mechanics might have impacted on ancient natural philosophy. Such an impact could take different forms, and it is important to be clear on what would count as a ‘mechanical’ or ‘mechanistic’ conception, using the term to describe a way of conceiving of the natural world by reference to mechanics. The question needs to be posed in a way that is neither too broad nor too narrow in scope, in order to appreciate what effects the discipline of mechanics might have had on natural philosophy.

At a time when mechanics was understood to work because of principles that could be identified and theorized, we might expect philosophers to consider the applicability of these principles to the study of other kinds of motion and its causes. But it is also possible for natural philosophers to take inspiration from mechanics independently of such a theoretical understanding. Experience with constructing devices might give rise to new ideas about the properties of matter, or the way it interacts. The presence of working artifacts that can approximate the functions taken to be definitive of animals might call into question the distinction in kind between organism and artifact, or suggest ways that animal functions might be realized by material means.

Historians agree on the importance, both to natural philosophy and to the development of the modern sciences, of the emergence of a ‘mechanical world picture’: many have studied its history, defining features and governing motivations. One important reason for the development of this world picture in the early modern period seems to have been the reintroduction of a number of ancient Greek texts. Rose and Drake suggest that it is no coincidence that the circulation of the Aristotelian Mechanica coincided with the formative period for modern science.

Against this background, it might seem necessary to account for the absence of any comparable interest, amongst the ancient Greeks themselves, in the implications of their mechanics for natural philosophy. A number of classic explanations have been offered as to why ancient Greek thinkers might not have seen the applicability of ideas from mechanics to the understanding of the natural world. I suggest that these explanations are spurious, and moreover that there is evidence of a philosophical reception of ideas from mechanics, especially in late antiquity. The evidence is scattered and often only preserved in the criticisms of its detractors: the dominant figures in late antique philosophy rejected the ‘mechanical hypothesis’. But its very existence is an interesting development that should not be overlooked.

Ancient Greek mechanics was a broad and diverse field, including a number of subfields concerned with different kinds of ‘working artifacts’ and the theory of their operation.

It is only in the seventeenth century that the term ‘mechanical’ came into common use to describe a way of doing natural philosophy. This appendix draws on the results of recent scholarly work on this period in disentangling different threads in the complex history of the term ‘mechanical’. There are several reasons for attempting to trace the reception of the ancient Greek tradition of mechanics in the seventeenth century. One is to show why twentieth-century usage, based as it is on an opposition that was formulated in the early modern period, is so multifaceted. A second is to justify my rejection of a scholarly commonplace that a view of mechanics Galileo rejects goes back to antiquity. The third is to indicate that the sense in which I have been writing of a ‘mechanical hypothesis’ in late antiquity is similar to the sense in which that phrase came to be used in the seventeenth century. Comparisons between the ancient and modern reception of mechanics are most often made by experts in the latter period; I hope it does not seem unduly hubristic to trace that reception from a different perspective. This is not of course intended as a complete account of the meanings of ‘mechanical’ in the seventeenth century but rather focuses on the reception of ‘mechanics’ in the ancient Greek sense. Because modern categories are shaped by seventeenth-century usage, attention to the shaping of those categories is a task that scholars of ancient Greek thought cannot avoid.

David Furley begins his work The Greek Cosmologists with a concise presentation of the differences between two main approaches to natural philosophy in antiquity. One of these, the teleological tradition, best represented by Aristotle, understands form to be explanatorily irreducible and holds that teleological explanations cannot be omitted from a complete account of the natural world. Philosophers in this tradition consider matter to be continuous and to have no imperceptible microstructure; they regard qualitative change as fundamental and not reducible to rearrangement of smallest parts; and they think of the material cosmos as structured and finite in extent. The atomists, by contrast, take all change to be fully explained by the spatial rearrangement of these smallest parts, without reference to any purposes these changes might be thought to serve. They take matter to be composed of indivisible smallest parts moving in a void, treat macroscopic structures as explanatorily reducible to the properties of the smallest parts and regard the universe as infinite and unstructured.

It is important to notice that the contrast between two competing approaches is not presented as a logically exhaustive dichotomy: neither in the ancient nor the modern world are these the only possible explanatory options. Furley's point is not simply to segregate philosophical positions according to an exhaustive and exclusive dichotomy, but to note an interesting tendency of philosophical positions to cluster around certain key assumptions.

To resume: this argument for the existence of a ‘mechanical hypothesis’ in ancient Greek natural philosophy began with a conceptual examination of the meaning of the terms ‘mechanical’ or ‘mechanistic’. I distinguished the use of the term ‘mechanical’ as a systematic description of perceived features of a view from the idea that the thinkers in question were explicitly motivated by their own conception of mechanics in formulating a view. Some ancient Greek thinkers can be described as ‘mechanistic’ in the latter sense, inasmuch as they did appeal to the field of mechanics to understand the natural world. This history has received less attention than it deserves.

A tendency to describe the ancient atomists as ‘mechanistic’ seems to have deterred scholars from looking for the impact of ancient Greek mechanics on late antique philosophy. Historians of science, meanwhile, have mistakenly concluded from some remarks of Galileo's that, in antiquity, mechanics was systematically excluded from natural philosophy. In the other direction, a few histories of technology think that ‘mechanistic conceptions’ can be found as far back as Homer. I set aside some misconceptions before studying the impact of ancient Greek mechanics on natural philosophy.

Tracing the history of mechanics, I argue that there is little evidence of it – in any sense of the term – from before the fourth century bce. Branches of the field were clearly developing in the fourth century. Nonetheless, there is little definitive evidence of what the term mēchanikē meant to Aristotle.