Plato: Natural Science

In this paper I examine the role of optimality reasoning in Aristotle’s natural science. By “optimality reasoning” I mean reasoning that appeals to some conception of “what is best” in order to explain why things are the way they are. We are first introduced to this pattern of reasoning in the famous passage at Phaedo 97b8-98a2, where (Plato’s) Socrates invokes “what is best” as a cause (aitia) of things in nature. This passage can be seen as the intellectual ancestor of (...) Aristotle’s own principle, expressed by the famous dictum “nature does nothing in vain but always what is best for the substance from among the possibilities concerning each kind of animal” (Progression of Animals II, 704b12-18). The paper is focused around exploring three questions that arise in connection with Aristotle’s use of this optimality principle: (1) How do we understand the concept of “the best” at work in the principle? (2) How does Aristotle conceive of “the range of possibilities”? And, finally, (3) what role does optimality reasoning play in Aristotle’s natural science? Is it a special form of demonstration in which the optimality principle functions as one of its premises, or is it a heuristic device that helps uncover those causally relevant features of a natural substances that ultimately serve as middle terms in demonstrations? In the final section I return to the comparison between Plato and Aristotle and argue that, while both see the natural world as the product of an optimizing agent and while both see this assumption as licensing a pattern of reasoning that appeals to a certain conception of “the best”, they disagree fundamentally over what the optimization agent is and how it operates. Thus, despite their general agreement, it would be a mistake to think that Aristotle simply took over Plato’s use of optimality reasoning without significant modifications. (shrink)

The intellectual history of evolutionary theory really does not begin in earnest until the late seventeenth/early eighteenth century. Prior to that, the idea that species might have evolved over time was not a serious possibility for most naturalists and philosophers. There is certainly no substantive debate in antiquity about evolution in the modern sense. There were really only two competing explanations for how living things came to have the parts they do: design or blind chance. Ancient Greek Atomism, for example, (...) taught that all composite bodies, including living things, are generated through the random collision of atoms as they rebel and move in the void. Plato and Aristotle both dismissed this possibility on the grounds that living things are too complex and too well-adapted to be products of chance. This eventually became the central premise in Galen’s own Argument from Design. That species forms might have gradually evolved over time by a process of natural selection was not seen as a plausible alternative. Of course, such a theory had been proposed by Empedocles in the fifth century BCE. But because his theory still relied heavily on chance, it was not taken seriously by any of the later ancient Greek or Roman thinkers. My aim in this paper is to investigate the reasons why evolutionary thinking failed to gain momentum in antiquity after its introduction by Empedocles. (shrink)

I argue that Plato thinks that the soul has location, surface, depth, and extension, and that the Timaeus’ composition of the soul out of eight circles is intended literally. A novel contribution is the development of an account of corporeality that denies the entailment that the soul is corporeal. I conclude by examining Aristotle’s objection to the Timaeus’ psychology and then the intellectual history of this reading of Plato.

This paper concerns the place of Plato’s eschatology in his philosophy. I argue that the theory of reincarnation appeals to Plato due to its power to explain how non-human animals came to be. Further, the outlines of this theory are entailed by other commitments, such as that embodiment disrupts psychic functioning, that virtue is always rewarded and vice punished, and that the soul is immortal. I conclude by arguing that Plato develops a view of reincarnation as the chief tool that (...) the gods have to ensure that virtue is victorious over vice throughout the whole cosmos. (shrink)

I argue that, according to Plato, the body is the sole cause of psychic disorders. This view is expressed at Timaeus 86b in an ambiguous sentence that has been widely misunderstood by translators and commentators. The goal of this article is to offer a new understanding of Plato’s text and view. In the first section, I argue that although the body is the result of the gods’ best efforts, their sub-optimal materials meant that the soul is constantly vulnerable to the (...) body’s influences. In the second section, I argue that every psychic disorder is a disruption of the motions of the inner psychic circles by the body; moreover, I defend my translation of 86b. In the final section, I argue that the goal of education is to restore the circles to their original orbits, and I disarm a possible objection that bad education is also a cause of psychic disorder. (shrink)

This paper concerns Plato’s characterization of the body as the soul’s tool. I take perception as an example of the body’s usefulness. I explore the Timaeus’ view that perception provides us with models of orderliness. Then, I argue that perception of confusing sensible objects is necessary for our cognitive development too. Lastly, I consider the instrumentality relationship more generally and its place in Plato’s teleological worldview.

Plato’s Timaeus reveals a cosmos governed by Necessity and Intellect; commentators have debated the relationship between them. Non-literalists hold that the demiurge, having carte blanche in taming Necessity, is omnipotent. But this omnipotence, alongside the attributes of benevolence and omniscience, creates problems when non-literalists address the problem of evil. We take the demiurge rather as limited by Necessity. This position is supported by episodes within the text, and by its larger consonance with Plato’s philosophy of evil and responsibility. By recognizing (...) the analogy between man and demiurge, the literal reading provides a moral component that its non-literal counterpart lacks. (shrink)

I defend, against its more recent critics, a literal, factual, and consistent interpretation of Timaeus’ creation of the cosmos and time. My main purpose is to clarify the assumptions under which a literal interpretation of Timaeus’ cosmology becomes philosophically attractive. I propose five exegetical principles that guide my interpretation. Unlike previous literalists, I argue that assuming a “pre-cosmic time” is a mistake. Instead, I challenge the exegetical assumptions scholars impose on the text and argue that for Timaeus, a mere succession (...) of events and the relations derived from it (before, after, simultaneous with) imply no time, given the narrow definition of the term used in the dialogue. For Timaeus, I explain, time is measurable, regular, and dependent on the motion of the celestial bodies. A mere succession of events like the one needed to understand the creation story and the pre-cosmos requires none of these elements. Readers of Plato erroneously assume that a succession of events implies time, but that is to impose a conception of time absent in the text. The chapter offers a detailed reconstruction of the pre-cosmic stage under a literalist interpretation and argues how it is compatible with the immutable relationship between the Demiurge and the cosmos. -/- This is an open access chapter distributed under the terms of the CC BY-NC 4.0 license. chapter 4. (shrink)

I argue that Plato believes that the soul must be both the principle of motion and the subject of cognition because it moves things specifically by means of its thoughts. I begin by arguing that the soul moves things by means of such acts as examination and deliberation, and that this view is developed in response to Anaxagoras. I then argue that every kind of soul enjoys a kind of cognition, with even plant souls having a form of Aristotelian discrimination (...) (krisis), and that there is therefore no completely unintelligent, evil soul in the cosmos that can explain disorderly motions; as a result, the soul is not the principle of all motion but only motion in the cosmos after it has been ordered by the Demiurge. (shrink)

This paper is about the history of a question in ancient Greek philosophy and medicine: what holds the parts of a whole together? The idea that there is a single cause responsible for cohesion is usually associated with the Stoics. They refer to it as the synectic cause (αἴτιον συνεκτικόν), a term variously translated as ‘cohesive cause,’ ‘containing cause’ or ‘sustaining cause.’ The Stoics, however, are neither the first nor the only thinkers to raise this question or to propose a (...) single answer. Many earlier thinkers offer their own candidates for what actively binds parts together, with differing implications not only for why we are wholes rather than heaps, but also why our bodies inevitably become diseased and fall apart. This paper assembles, up to the time of the Stoics, one part of the history of such a cause: what is called ‘the synechon’ (τὸ συνέχον) – that which holds things together. Starting with our earliest evidence from Anaximenes (sixth century BCE), the paper looks at different candidates and especially the models and metaphors for thinking about causes of cohesion which were proposed by different philosophers and doctors including Empedocles, early Greek doctors, Diogenes of Apollonia, Plato and Aristotle. My goal is to explore why these candidates and models were proposed and how later philosophical objections to them led to changes in how causes of cohesion were understood. (shrink)

This paper aims to show that—and how—Plato’s notion of the receptacle in the Timaeus provides the conditions for developing a mathematical as well as a physical space without itself being space. In response to the debate whether Plato’s receptacle is a conception of space or of matter, I suggest employing criteria from topology and the theory of metric spaces as the most basic ones available. I show that the receptacle fulfils its main task–allowing the elements qua images of the Forms (...) to exist as sensible things by being that in which the elements appear, change and move–in virtue of being pure continuity. All further qualifications required for a full notion of space are derived solely from the content of the receptacle. (shrink)

One aim of this paper is to bring to the surface the problems with the traditional, non-literal interpretation of the pre-cosmos in the Timaeus. Contrary to this traditional interpretation, I show that Necessity is an ateleological cause capable of bringing about the events in the pre-cosmos, and that Intelligence is a teleological cause that produces effects only for the sake of maximizing the good. I conclude that there are no grounds for supposing that Intelligence is a causal force operating in (...) the pre-cosmos, and that the account of the pre-cosmos should be taken literally: it is an account of the works of Necessity alone. (shrink)

Epicurean philosophy, as Epicurus's teachings became known, was used as the basis for how the community lived and worked. At the time, founding a school and teaching a community of students was the main way philosophical ideas were developed and transmitted. Greek philosopher Aristotle (384–322 BCE), for instance, founded a school in Athens called the Lyceum. Epicurus and his disciples believed either there were no gods or, if there were, the gods were so remote from humans that they were not (...) worth worrying about. Similarly, humans would not have to worry about the afterlife. Instead, humans should live by maximizing their pleasure. The highest pleasure was to be found in the absence of pain. Epicurus taught that humans could maximize their pleasure by living simply and enjoying those impulses that are natural to humans. These impulses include the need to eat and the desire for good friends and company. The Principal Doctrines are 40 statements outlining the basis for the beliefs of Epicurus and his followers about how to lead a good life. Epicurus's other philosophical beliefs (such as his belief that existence was composed of indivisible particles called atoms) are expressed in other writings. Almost none of Epicurus's original writings survive to the present day. His works, including the Principal Doctrines, are known to us because of the work of later writers. In the 3rd century CE, Diogenes Laërtius reproduced Epicurus's writings in Lives, Teachings, and Sayings of Famous Philosophers. Produced centuries after Epicurus's death, such collections may not be Epicurus's precise words or formulations. The Principal Doctrines should thus be regarded as the core principles not only of Epicurus but also of his followers, the Epicureans. (shrink)