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 develop an account of the role that biology plays in the Timaeus’ view of nous and other aspects of cognitive life. I begin by outlining the biology of human cognition. I then argue that these biological views shine an important light on different aspects of the soul. I then argue that the human body is particularly friendly to nous, paying special attention to the heart and the liver. I next consider the ways that the body fails to protect our (...) nous. I conclude by comparing human nous with the cognition of non-humans. (shrink)

This is an impressive and important book about perception in Plato’s Timaeus, but most of its readers will probably be researchers who are interested in much broader questions about the dialogue. There is nothing deficient or lacking about this treatment of perception, but this book should be put alongside Thomas Johansen’s Plato’s Natural Philosophy and Sarah Broadie’s Nature and Divinity in the sense that this is, for all intents and purposes, a monograph about the whole Timaeus, even though it is (...) pitched as being focused on perception. There are only a few topics missing, such as the nature of the cosmic receptacle and psychic diseases. Virtually everything else, including the status of Timaeus’ so-called likely story, the generation of the lower gods, and the nature of bone, is discussed at length. (shrink)

This article concerns the so-called irrigation system in the Timaeus' biology (77a–81e), which replenishes our body’s tissues with resources from food delivered as blood. I argue that this system functions mainly by the natural like-to-like motion of the elements and that the circulation of blood is an important case study of Plato’s physics. We are forced to revise the view that the elements attract their like. Instead, similar elements merely tend to coalesce with each other in virtue of their tactile (...) features as the atomists describe. The notion of attraction is replaced with this notion of mere coalescence. I begin by outlining how blood is made from food. I then argue that an understanding of health and disease compels us to read Plato as if he were an atomist and to abandon the popular scholarly interpretations according to which the elements attract each other. (shrink)

In this article, I make the case for the continued relevance of Plato’s Timaeus. I begin by sketching Allan Bloom’s picture of the natural sciences today in The Closing of the American Mind, according to which the natural sciences are, objectionably, increasingly specialized and have ejected humans qua humans from their purview. I argue that Plato’s Timaeus, despite the falsity of virtually all of its scientific claims, provides a model for how we can pursue scientific questions in a comprehensive way (...) that stresses their connections to other disciplines, including the humanities, and that puts humanity qua humanity back in the picture. I then argue that being led by Plato’s philosophy to return humanity conceptually to the natural world can improve our thinking regarding climate change and other important environmental crises. (shrink)

This is an essay on perception and its objects in the Timaeus. Two features of this work are noteworthy. First, the emphasis throughout is on Timaeus' views and not Plato's. Second, I show how broader aspects of Timaeus' cosmology are directly relevant to his philosophy of perception.

The relationship between mind and necessity is one of the major points of difficulty for the interpretation of Plato’s Timaeus. At times Timaeus seems to say the demiurge is omnipotent in his creation, and at other times seems to say he is limited by pre-existing matter. Most interpretations take one of the two sides, but this paper proposes a novel approach to interpreting this issue which resolves the difficulty. This paper suggests that in his speech Timaeus presents two hypothetical models (...) of creation, one with an omnipotent demiurge and one where he is limited by matter, so as to investigate their theoretical and empirical validity. Further, he shows that each model is ultimately an inadequate explanation of the first principles of the cosmos. Timaeus’ speech is therefore properly understood to be aporetic: it leaves its listeners aware of the difficulties inherent in the two models of creation, but without a more viable alternative. (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.

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 article 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)

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)

Scholarship on Plato's Timaeus has paid relatively little attention to Tim. 77a–81, a seemingly disjointed passage on topics including plants, respiration, blood circulation, and musical sounds. Despite this comparative neglect, commentators both ancient and modern have levelled a number of serious charges against Timaeus' remarks in the passage, questioning the coherence and explanatory power of what they take to be a theory of respiration. In this paper, I argue that the project of 77a–81e is not to sketch theories of respiration, (...) circulation, and digestion, but to explain how the human body is maintained in light of and despite constant environmental depletion. Further, I argue that in order to understand this account of “the replenishing system,” we need to understand Timaeus' striking analogy of the fish trap or nassa. Commentators have generally focused directly on the workings of the bodily construction that Timaeus likens to a fish trap, but without considering how we should understand the analogy qua analogy. I develop a functional reading of the analogy that yields a coherent account of the replenishing system on which previous criticisms of Timaeus' remarks on respiration do not arise. Aside from lending greater unity to the passage, both internally and within its immediate context in the dialogue, this account of the replenishing system contributes to our understanding of Timaeus' reason-and-necessity explanatory framework as applied to the human body and has noteworthy implications for specific explanatory principles, in particular like-to-like motion and circular thrust. (shrink)

This paper provides a rational reconstruction of a Platonic trope bundle theory that is a live alternative to contemporary bundle theories. According to the theory, Platonic particulars are composed of what Plato calls images of Forms; contemporary metaphysicians call these tropes. Tropes are dependent on Forms and the Receptacle, while trope bundles are structured by natural kinds using the Phaedo's principles of inclusion and exclusion and the Timaeus’ geometrised elements, as well as by co-location in the Receptacle. Key elements of (...) discussion include persistence and abundance of Plato's tropes. The resulting theory is compared with contemporary trope bundle theories. (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)

At Plato’s Phaedrus 270c, Socrates asks whether one can know souls without knowing ‘the whole.’ Phaedrus answers that ‘according to Hippocrates’ the same demand on knowing the whole applies to bodies. What parallel is intended between soul-knowledge and body-knowledge and which medical passages illustrate the analogy have been much debated. Three dominant interpretations read ‘the whole’ as respectively (1) environment, (2) kosmos, and (3) individual soul or body; and adduce supporting Hippocratic passages. But none of these interpretations accounts for the (...) Phaedrus’ rhetorical method. A better reading sees the whole as the genos ‘soul,’ as the Phaedrus’ taxonomies divide that genus. (shrink)

A teleological explanation is an explanation in terms of an end or a purpose. So saying that ‘X came about for the sake of Y’ is a teleological account of X. It is a striking feature of ancient Greek philosophy that many thinkers accepted that the world should be explained in this way. However, before Aristotle, teleological explanations of the cosmos were generally based on the idea that it had been created by a divine intelligence. If an intelligent power made (...) the world, then it makes sense that it did so with a purpose in mind, so grasping this purpose will help us understand the world. This is the pattern of teleological explanation that we find in the Presocratics and in Plato. However, with Aristotle teleology underwent a change: instead of thinking that the ends were explanatory because a mind had sought to bring them about, Aristotle took the ends to operate in natural beings independently of the efforts of any creative intelligence. Indeed, he thought that his predecessors had failed to understand what was distinctive of nature, namely, that its ends work from the inside of natural beings themselves. (shrink)

In this paper, I propose a new reading of Phaedo 99b6-d2. My main thesis is that in 99c6-9, Socrates does not refer to the teleological αἰτία but to the αἰτία that will be provided by a stronger ‘Atlas’ (99c4-5). This means that the passage offers no evidence that Socrates abandons teleology or modifies his views about it. He acknowledges, instead, that he could not find or learn any αἰτία stronger than the teleological one. This, I suggest, allows an interpretation of (...) the Phaedo in which Socrates offers a consistent account of the αἰτία of generation and destruction. (shrink)

This chapter contains sections titled: Going Beyond Nature in Order to Explain it Technē, epistēmē and alēthēs doxa Mathematics, pure and applied Observation and Experimental Verification Bibliography.

The third part of the Timaeus, where the account is focused on the cooperation of reason and necessity, has received far less attention than the opening two sections. Particularly, the description of irrigation, digestion and respiration constitutes a challenging passage that has been conspicuously overlooked by scholarly research. Virtually the only modern explanation for the passage was devised by Cornford, and despite several inaccuracies it has been unanimously accepted by all commentators. This paper will challenge Cornford’s interpretation, and use some (...) modern biological concepts to provide an alternative approach to the passage more compatible with an actual human body. (shrink)

In the tripartite psychology of the Republic, Plato characterizes the “spirited” part of the soul as the “ally of reason”: like the auxiliaries of the just city, whose distinctive job is to support the policies and judgments passed down by the rulers, spirit’s distinctive “job” in the soul is to support and defend the practical decisions and commands of the reasoning part. This is to include not only defense against external enemies who might interfere with those commands, but also, and (...) most importantly, defense against unruly appetites within the individual’s own soul.1 Spirit, according to this picture, is by nature reason’s faithful auxiliary in the soul, while appetite is always a potential enemy to be watched .. (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)

The paper is concerned with the medical and the biological sources of Protagoras' views.

In this paper I contend that the 'superfluity' of triangles is only apparent; all those specified are indeed required for the smallest sub-units, so long as the symmetry of the final body to be constructed is taken into account at earlier stages.

The paper examines the account of the mortal parts of the human soul in theTimaeus. What is their nature? What is their relationship to the immortal part of the soul and its inner structure on the one hand, and to the body and its organs and their functioning on the other? Are they incorporeal or corporeal? What kind of movement do they have? In what sense precisely are they ‘another kind of soul’ ?

The Receptacle of the title is, of course, the ‘Receptacle of all becoming’ in Plato’s Timaeus. Plato likens it to a ‘nurse’, and even calls it a ‘mother’. He speaks of it as that in which its contents come to be, only in their turn to disappear from it. He compares it to a mass of gold which someone incessantly remoulds into different shape. He declares it completely unchanging: ‘it does not depart from its own character in any way'. What (...) is its character? It is the character of possessing and acquiring no character similar to that of any of the objects said to enter it and disappear from it. Plato says too that it is space; the receptacle is what makes it true that each of those objects is somewhere. And finally, as if he had not already given us far too much to digest of this very rich subject, Plato adds that the Receptacle shakes its contents with a sort of winnowing motion, and in fact was already doing this even before the craftsman god had formed this world of ours. The question of this paper is: what is the function of this multifariously conceived entity, or principle, the Receptacle? I shall approach by asking what its contents are. (shrink)

This appears in a supplementary issue of the Bulletin of the Institute of Classical Studies, entitled "Ancient Approaches to Plato's Timaeus.".

The figure of the cordial host of the Academy, who invited the most gifted mathematicians and cultivated pure research, whose keen intellect was able if not to solve the particular problem then at least to show the method for its solution: this figure is quite familiar to students of Greek science. But was the Academy as such a center of scientific research, and did Plato really set for mathematicians and astronomers the problems they should study and methods they should use? (...) Our sources tell about Plato's friendship or at least acquaintance with many brilliant mathematicians of his day (Theodorus, Archytas, Theaetetus), but they were never his pupils, rather vice versa -- he learned much from them and actively used this knowledge in developing his philosophy. There is no reliable evidence that Eudoxus, Menaechmus, Dinostratus, Theudius, and others, whom many scholars unite into the group of so-called "Academic mathematicians," ever were his pupils or close associates. Our analysis of the relevant passages (Eratosthenes' Platonicus, Sosigenes ap. Simplicius, Proclus' "Catalogue of geometers", and Philodemus' "History of the Academy", etc.) shows that the very tendency of portraying Plato as the architect of science goes back to the early Academy and is born out of interpretations of his dialogues. (shrink)

Now with extra footnotes, by editorial demand! Final version accepted by Oxford Studies in Ancient Philosophy. -/- This essay consists in a trick and a potential insight. The trick consists in a minimalist interpretation of color mixture. The account of color mixture is minimalist in the sense that, given certain background assumptions, there is no more to Timaeus’ account of color mixture than the list of the chromatic pathēmata and the list of how these combine to elicit perceptions of all (...) the colors. The only potential controversial elements of the minimalist interpretation are the relevant background assumptions and the interpretation of the chromatic pathēmata. The potential insight concerns a motive that Plato, in the guise of Timaeus, may have for presenting an account of color mixture. Specifically, I shall argue that on the minimalist interpretation, Plato may be read as reconciling the Democritrean four color scheme with an older tradi- tion where white and black are the fundamental chromatic opposition. As we shall see, this bears on the interpretation of the chromatic pathēmata. (shrink)