Aristotle: Cosmology

Many contemporary philosophers hold that comparison requires a common, monistic ‘covering value’, and Aristotle is often described as a forerunner of this view. This paper reconsiders that claim. First, its textual warrant is substantially weaker than has been thought. Philosophically, moreover, Aristotle’s theory of non-synonymous predication allows for comparisons to be made using the special kind of non-synonymous terms that he calls pros hen legomenon, literally those ‘said with reference to a single thing.’ His favourite example is ‘healthy’ as said (...) of food, organisms, and medical procedures: these various senses are not entirely synonymous, yet are not simply unconnected. This has significant implications. Aristotle famously holds that goodness is species-specific, and it would then seem that species cannot be ranked according to how good they are. Yet Aristotle does—frequently—rank species. The paper shows us that he is not, pace other scholars, thereby caught in a contradiction. -/- . (shrink)

According to Avicenna, whatever exists, whenever it exists, exists of necessity. Not all beings, however, exist with the same kind of necessity: some things exist necessarily per se and others necessarily per aliud. Avicenna on the Necessity of the Actual: His Interpretation of Four Aristotelian Arguments explains how Avicenna’s modal claims show that God is the first efficient and the ultimate final cause of an eternally existing cosmos. In particular, Celia Kathryn Hatherly shows how Avicenna uses four Aristotelian arguments to (...) prove this very un-Aristotelian conclusion. These arguments include Aristotle's argument for the finitude of efficient causes in Metaphysics 2; for the prime mover in the Physics and Metaphysics 12; for the mutual entailment between the necessary and the eternal in De Caelo 1.12; and against the Megarians in Metaphysics 9. Moreover, Hatherly contends, when Avicenna's version of these arguments is interpreted using his distinctive understanding of modality, the objections of his contemporaries and modern scholars fail. (shrink)

I argue that the science of the soul only covers sublunary living things. Aristotle cannot properly ascribe ψυχή to unmoved movers since they do not have any capacities that are distinct from their activities or any matter to be structured. Heavenly bodies do not have souls in the way that mortal living things do, because their matter is not subject to alteration or generation. These beings do not fit into the hierarchy of soul powers that Aristotle relies on to provide (...) unity to ψυχή. Their living consists in their activities, not in having a capacity for activity. (shrink)

Aristotle’s theory of human happiness in the Nicomachean Ethics explicitly depends on the claim that contemplation (theôria) is peculiar to human beings, whether it is our function or only part of it. But there is a notorious problem: Aristotle says that divine beings also contemplate. Various solutions have been proposed, but each has difficulties. Drawing on an analysis of what divine contemplation involves according to Aristotle, I identify an assumption common to all of these proposals and argue for rejecting it. (...) This allows a straightforward solution to the problem and there is evidence that Aristotle would have adopted it. (shrink)

This article presents a few research findings related to the Geomantia attributed to William of Moerbeke. It consists of three sections: The first provides evidence for the classification of the Geomantia within the genre of the medieval compilations. The second includes a comparison of the Geomantia with the Ars geomantie nova of Batholomew of Parma and a few considerations on the datation of the treatise attributed to Moerbeke, based on this assessment. The third brings to the attention of scholars an (...) unpublished marginal note concerning the date of composition of the Geomantia. (shrink)

Near the beginning of De Gen. et Cor. II.1, Aristotle claims that the generation and corruption of all naturally constituted substances are “not without the perceptible bodies”. It is not clear what he intends by this. In this paper I offer a new interpretation of this assertion. I argue that the assumption behind the usual reading, namely, that these “perceptible bodies” ought to be distinguished from the naturally constituted substances, is flawed, and that the assertion is best understood as a (...) claim that Aristotle has established in the second half of the first book of the De Gen. et Cor. (shrink)

How did the ancient Greeks and Romans conceptualise order? This book answers that question by analysing the formative concept of kosmos in ancient literature, philosophy, science, art, and religion. This concept encouraged the Greeks and Romans to develop theories to explain core aspects of human life, including nature, beauty, society, politics, the individual, and what lies beyond human experience. Hence, Greek kosmos, and its Latin correlate mundus, are subjects of profound reflection by a wide range of important ancient figures, including (...) philosophers, poets and playwrights, intellectuals, and religious exegetes. By revealing kosmos in its many ancient manifestations, this book asks us to rethink our own sense of 'order', and to reflect on our place within a broader cosmic history. (shrink)

The concept of kosmos did not play the leading role in Aristotle’s physics that it did in Pythagorean, Atomistic, Platonic, or Stoic physics. Although Aristotle greatly influenced the history of cosmology, he does not himself recognize a science of cosmology, a science taking the kosmos itself as the object of study with its own phenomena to be explained and its own principles that explain them. The term kosmos played an important role in two aspects of his predecessor’s accounts that Aristotle (...) rejected: first, cosmogeny and kosmopoiia, generation or creation of the kosmos; second, diakosmêsis, arranging of a plurality of kosmoi. Aristotle was extremely critical of accounts involving kosmopoiia and diakosmêsis and he developed general dialectical strategies against them. In emphatically distinguishing his view from all his predecessors (including Plato), he uses the terms ho ouranos (the heaven), to holon (the whole), and to pan (the totality) in preference to ho kosmos (the kosmos or world). There is usually no harm in speaking loosely of ‘Aristotle’s cosmology’ when referring to his concept of the order of nature and the ouranos. Nevertheless, Aristotle’s theoretical philosophy offers something very different from those of his predecessors for whom kosmos was a keyword. (shrink)

Attempts to find perennial elements in Aristotle’s cosmology are doomed to failure because his distinction of sub- and supra-lunary realms no longer holds. More fruitful approaches to the contemporary importance of Aristotelian cosmology must focus on parities of reasoning rather than content. This paper highlights the striking parallels between Aristotle’s use of symmetry arguments in cosmology and instances of Noether’s First Theorem in contemporary physics. Both observe simple motion, find symmetries in that motion, argue from those symmetries to notions of (...) conservation, and then conclude to cosmological structure. These parallels reveal an enduring relevance for Aristotelian cosmology that does not depend on positing an enduring content to his cosmological claims. (shrink)

I examine the reasons Aristotle presents in Physics VIII 8 for denying a crucial assumption of Zeno’s dichotomy paradox: that every motion is composed of sub-motions. Aristotle claims that a unified motion is divisible into motions only in potentiality (δυνάμει). If it were actually divided at some point, the mobile would need to have arrived at and then have departed from this point, and that would require some interval of rest. Commentators have generally found Aristotle’s reasoning unconvincing. Against David Bostock (...) and Richard Sorabji, inter alia, I argue that Aristotle offers a plausible and internally consistent response to Zeno. I defend Aristotle’s reasoning by using his discussion of what to say about the mobile at boundary instants, transitions between change and rest. There Aristotle articulates what I call the Changes are Open, Rests are Closed Rule: what is true of something at a boundary instant is what is true of it over the time of its rest. By contrast, predications true of something over its period of change are not true of the thing at either of the boundary instants of that change. I argue that this rule issues from Aristotle’s general understanding of change, as laid out in Phys. III. It also fits well with Phys. VI, where Aristotle maintains that there is a first boundary instant included in the time of rest, but not a “first in which the mobile began to change.” I then show how this rule underlies Aristotle’s argument that a continuous motion cannot be composed of actual sub-motions. Aristotle distinguishes potential middles, points passed through en route to a terminus, from actual middles. The Changes are Open, Rests are Closed Rule only applies to actual middles, because only they are boundaries of change that the mobile must arrive at and then depart from. On my reading, Aristotle argues that the instant of arrival, the first instant at which the mobile has come to be at the actual middle, cannot belong to the time of the subsequent motion. If it did, the mobile would already be moving towards the next terminus and thus, per Phys. VI 6, would have already left. But it cannot have moved away from the midpoint at the very same moment it has arrived there. This means that the instant of arrival must be separated from the time of departure by an interval of rest. I show how Aristotle’s reasoning applies generally to rule out any continuous reflexive motion or continuous complex rectilinear motion. On my interpretation, however, the argument does not apply to every change of direction. When, as in the case of projectile motion, multiple movers and their relative powers explain why the mobile changes directions, distinct sub-motions are not involved. Aristotle holds that such motions cannot be continuous, not because they involve intervals of rest, but because they involve multiple causes of motion. My interpretation of the Changes are Open, Rests are Closed Rule allows us to make better sense of Aristotle’s argument than any previous interpretation. (shrink)

Ch.9 of Metaph. 12 gives no support to the common view (against which I have argued elsewhere) that in ch.7 Aristotle identifies his Prime Mover not only as a god but also as an intellect. Rather, ch.9 approaches the divinity of intellect as a common belief (ἔνδοξον) from the Greek philosophical and poetic tradition (as at ch.7, 1072b23) that now requires dialectical testing. Here Aristotle initially establishes that there is a most active intellect (proposed ch.7, 1072b18–19: demonstrated ch.9, 1074b17–21, b28–9), (...) and that it contemplates what is best (proposed loc. cit.: demonstrated ch.9, 1074b21–7). Thus ch.9 proceeds by deducing, as a new result, characteristics implying that this intellect is itself the Prime Mover, since its object, qua best, must be the god of ch.7, and divine intellect is essentially identical (1074b33–1074a5), and an indivisible unity (a5–10), with that object. (shrink)

Journal Name: Apeiron Issue: Ahead of print.

Aristotle argued that in theory one could acquire knowledge of the natural world. But he did not stop there; he put his theories into practice. This volume of new essays shows how Aristotle's natural science and philosophical theories shed light on one another. The contributors engage with both biological and non-biological scientific works and with a wide variety of theoretical works, including Physics, Generation and Corruption, On the Soul, and Posterior Analytics. The essays focus on a number of themes, including (...) the sort of explanation provided by matter; the relationship between matter, teleology, and necessity; cosmic teleology; how an organism's soul and faculties relate to its end; how to define things such as sleep, void, and soul; and the proper way to make scientific judgments. The resulting volume offers a rich and integrated view of Aristotle's science and shows how it fits with his larger philosophical theories. (shrink)

_ Source: _Volume 60, Issue 1, pp 88 - 126 The dominant interpretation of Metaphysics Θ.8 commits Aristotle to the claim that the heavenly bodies’ eternal movements are not the exercises of capacities. Against this, I argue that these movements are the result of necessarily exercised capacities. I clarify what it is for a heavenly body to possess a nature and argue that a body’s nature cannot be a final cause unless the natural body possesses capacities that are exercised for (...) the sake of its nature qua form. This discussion yields a better understanding of what capacities are, what explanatory work capacities do, and what it is to possess a nature. (shrink)

Starting with Aristotle and moving on to Darwin, Marco Solinas outlines the basic steps from the birth, establishment and later rebirth of the traditional view of living beings, and its overturning by evolutionary revolution. The classic framework devised by Aristotle was still dominant in the 17th Century world of Galileo, Harvey and Ray, and remained hegemonic until the time of Lamarck and Cuvier in the 19th Century. Darwin's breakthrough thus takes on the dimensions of an abandonment of the traditional finalistic (...) theory. It was a transition exemplified in the morphological analysis of useless parts, such as the sightless eyes of moles, already discussed by Aristotle, which Darwin used as a crowbar to unhinge the systematic recourse to final causes. With many excerpts, a chronological sequence and an analytical approach, this book follows the course of the two conceptions that have shaped the destiny of life sciences in western culture. (shrink)

In developing his theory of aether in De Caelo 1, Aristotle argues, in DC 1.4, that one circular motion cannot be contrary to another. In this paper, I discuss how Aristotle can maintain this position and accept the existence of celestial spheres that rotate in contrary directions, as he does in his revision of the Eudoxan theory in Metaphysics 12.8.

Il est relativement peu de textes qui, dans le De Cœlo, témoignent de l’existence de réalités incorporelles transcendantes à l’ordre astral. La conclusion, sur laquelle se referme la démonstration de l’unicité du ciel en I 9, est-elle de ceux‑là? Les « êtres de là-bas » y désignent-ils les réalités sidérales les plus hautes ou certaines instances hypercosmiques? C’est à l’identification de ces êtres qu’il s’agit ici de procéder. En montrant que convergent ensemble les indices textuels du passage et son homogénéité (...) démonstrative, il pourra alors apparaître que ces êtres, dont Aristote vante l’immutabilité et la perfection, transcendent l’ordre céleste, sans qu’on puisse toutefois déterminer la relation exacte qui les unit au ciel, obérant ainsi la possibilité de lire, à travers eux, une référence implicite à la doctrine du Premier Moteur Immobile. (shrink)

This article examines three passages of De caelo in order to discuss Aristotle’s epistemological attitude towards the theories advanced by him and towards the possibility of progress in the scientific research of the celestial world. I argue that, although the possibility of progress in scientific investigation is not central in Aristotle’s reflections, progress is not ruled out either as impossible or as undesirable.

New Perspectives on Aristotle'sDe caelo (Leiden) 139-161. Machamer, PK (1978) " Aristotle on Natural Place and Motion" Isis 69: 377-387. ...

For Averroes, celestial circulation is evidence of a divinely mandated rational universe. This paper follows Averroes’ account on cosmic contact between the eternal and the temporal, in Tahafūt al-tahafūt contra al-Ghazālī. It argues that the polemical perspective of the Tahafūt al-tahafūt frames Averroes’ appeal to Aristotle’s account of cosmic motion. Consequently, Averroes’ exceptional account of the universe contrasts Aristotle’s exemplary account of the mutual participation of intellect and nature. Their accounts of celestial circulation implicate the status of human nature conditioned (...) by cosmic nature. As such, the possibility of human freedom rests on the nature of causality between divine intellect and cosmic manifestation. The convergence and divergence of Aristotle and Averroes regarding celestial circulation reveals Averroes’ politics that guide a rational argument for a strong cosmic causal connection between the unmoved mover and the universe, against al-Ghazālī’s rationally inaccessible divine will. (shrink)

Monte Johnson examines one of the most controversial aspects of Aristiotle's natural philosophy: his teleology. Is teleology about causation or explanation? Does it exclude or obviate mechanism, determinism, or materialism? Is it focused on the good of individual organisms, or is god or man the ultimate end of all processes and entities? Is teleology restricted to living things, or does it apply to the cosmos as a whole? Does it identify objectively existent causes in the world, or is it merely (...) a heuristic for our understanding of other causal processes? Johnson argues that Aristotle's aporetic approach drives a middle course between these traditional oppositions, and avoids the dilemma, frequently urged against teleology, between backwards causation and anthropomorphism. Although these issues have been debated with extraordinary depth by Aristotle scholars, and touched upon by many in the wider philosophical and scientific community as well, there has been no comprehensive historical treatment of the issue. Aristotle is commonly considered the inventor of teleology, although the precise term originated in the eighteenth century. But if teleology means the use of ends and goals in natural science, then Aristotle was rather a critical innovator of teleological explanation. Teleological notions were widespread among his predecessors, but Aristotle rejected their conception of extrinsic causes such as mind or god as the primary causes for natural things. Aristotle's radical alternative was to assert nature itself as an internal principle of change and an end, and his teleological explanations focus on the intrinsic ends of natural substances - those ends that benefit the natural thing itself. Aristotle's use of ends was subsequently conflated with incompatible 'teleological' notions, including proofs for the existence of a providential or designer god, vitalism and animism, opposition to mechanism and non-teleological causation, and anthropocentrism. Johnson addresses these misconceptions through an elaboration of Aristotle's methodological statements, as well as an examination of the explanations actually offered in the scientific works. Reviewed in: Notre Dame Philosophical Review 2006.06.15; Bryn Mawr Classical Review 2006.08.37; Il-Sole – 24 Ore 6 Aug. 2006; Philosophy in Review 26 (2006): 360-2; Rhizai 3 (2006): 171-8; Journal of the History of Philosophy 45 (2007): 323-4; Ancient Philosophy 27 (2007): 191-200; Phronesis 52 (2007): 248-9; Isis 98 (2007): 375; Aestimatio 4 (2007) 146-152; The British Journal for the History of Science 41 (2008): 129-130. The European Legacy 14 (2009); La Cultura 47 (2009): 174-175; Sean M. Row, Teleology in Political Contexts: an assessment of Monte Ransome Johnson’s “Aristotle on Teleology”. (A thesis presented to the faculty of the college of arts and sciences of Ohio University, 2009.). (shrink)

It is commonly assumed that Aristotle denies any real existence to infinity. Nothing is actually infinite. If, in order to resolve Zeno’s paradoxes, Aristotle must talk of infinity, it is only in the sense of a potentiality that can never be actualized. Aristotle’s solution has been both praised for its subtlety and blamed for entailing a limitation of mathematic. His understanding of the infinite as simply indefinite (the “bad infinite” that fails to reach its accomplishment), his conception of the cosmos (...) and even its prime mover as finite (in the sense of autarchic/self-contained) have been contrasted with the subsequent claim of God as ens infinitum (understood as a “positive” infinity). The goal of this essay is to reexamine the major texts (notably De caelo) and to demonstrate that (1) Aristotle’s claim according to which there is no actual infinite concerns only substances, not processes. (2) That Aristotle does not deny an actual infinite as such. (3) That when considering time and God (qua eternal) Aristotle acknowledges an actual infinite. (shrink)

The world is configured in ways that seem systematically hospitable to life forms, especially the human race. Is this the outcome of divine planning or simply of the laws of physics? Ancient Greeks and Romans famously disagreed on whether the cosmos was the product of design or accident. In this book, David Sedley examines this question and illuminates new historical perspectives on the pantheon of thinkers who laid the foundations of Western philosophy and science. Versions of what we call the (...) "creationist" option were widely favored by the major thinkers of classical antiquity, including Plato, whose ideas on the subject prepared the ground for Aristotle's celebrated teleology. But Aristotle aligned himself with the anti-creationist lobby, whose most militant members—the atomists—sought to show how a world just like ours would form inevitably by sheer accident, given only the infinity of space and matter. This stimulating study explores seven major thinkers and philosophical movements enmeshed in the debate: Anaxagoras, Empedocles, Socrates, Plato, the atomists, Aristotle, and the Stoics. (shrink)

This new translation of _De Caelo_ fits seamlessly with other volumes in the New Hackett Aristotle series, enabling Anglophone readers to study Aristotle’s work in a way previously not possible. The Introduction describes the book that lies ahead, explaining what it is about, what it is trying to do, how it goes about doing it, and what sort of audience it presupposes. Sequentially numbered endnotes provide the information most needed at each juncture, while a detailed Index indicates the places where (...) focused discussion of key notions occurs. (shrink)

Aristotle asserts at 1073b10-13 that he intends to give in Metaphysics XII.8 a definite conception about the multitude of the divine transcendent entities, which function as the movers of the celestial spheres. In order to do so, he describes several celestial theories. First Eudoxus’s, then the modifications of this theory propounded by Callippus, and finally his own suggestion, the introduction of yet further spheres which integrate the celestial spheres into a single overarching scheme. For this, after explaining the spheres providing (...) the component motions of each planet, Aristotle introduces so-called rewinding spheres (anelittousai), which perform contrary revolutions to the ones performed by the spheres carrying the planet. (shrink)

A review of Helen Lang's monograph on Aristotle's physics.

David Furley's work on the cosmologies of classical antiquity is structured around what he calls "two pictures of the world." The first picture, defended by both Plato and Aristotle, portrays the universe, or all that there is (to pan), as identical with our particular ordered world-system. Thus, the adherents of this view claim that the universe is finite and unique. The second system, defended by Leucippus and Democritus, portrays an infinite universe within which our particular kosmos is only one of (...) countless kosmoi. Aristotle's argument in De caelo I.9 that the world is necessarily unique is an important contribution to this debate. This argument holds interest because it shows Aristotle wrestling with an apparent inconsistency in his own philosophy, as deeply-held convictions within his cosmology collide with an equally deeply-held conviction within his metaphysics. The following three principles, each of which Aristotle appears committed to, are inconsistent: -/- The cosmic uniqueness principle. The world is necessarily unique. The cosmic form principle. The world is an ordered, structured unity. As such, the world has a form. The possibility of multiple instantiation principle. For all F, if F is a form, it is possible that there exist multiple Fs. In De caelo I.9, Aristotle argues that we can establish the uniqueness of the universe, reject the multiple instantiation principle, yet still retain the distinction between 'this world' and 'world in general,' if the following is true (as it is): the world takes up all the matter that exists. Aristotle illustrates this argument with one of the stranger analogies in his corpus: imagine an aquiline nose that takes up all the flesh in the universe. If this were so, then there could not exist any other aquiline objects whatsoever. (For this reason, we dub the De caelo I.9 argument the 'Cosmic Nose argument.') This paper is an interpretation of how this argument is supposed to proceed and an assessment of its success. The first section states the problem Aristotle is confronted with, sorts through Aristotle's various statements of the Cosmic Nose argument, which exhibit some sloppiness, and reconstructs charitably a single argument. We also spend some time examining the significance of Aristotle's example of a gigantic aquiline nose. We argue that, even charitably reconstructed, the argument appears to commit a serious modal fallacy. The remainder of the paper explores whether this modal fallacy can be overcome. We conclude that, although not a cogent argument for the uniqueness of the world (as this would require a significant revision of our current astronomy), the Cosmic Nose argument does succeed on its own terms. However, it should not be regarded as a free-standing argument for the uniqueness of the world. Instead, it depends crucially on the earlier argument in De caelo I.8 for the universe's uniqueness; De caelo I.9 should be viewed as an attempt to extend the conclusion of De caelo I.8 and to show how this conclusion can be made consistent with Aristotle's metaphysical principles about the nature of form. (shrink)

Argues that Aristotle regarded the universe, or Totality, as a single substance with form and matter, and that he regarded this substance together with the Prime Mover as a self-mover.

With the introduction of Greco-Islamic science and natural philosophy, medieval natural philosophers were confronted with three distinct astronomical systems: Aristotelian, Ptolemaic, and the system of al-Bitruji. A fundamental problem that each had to confront was how to explain simultaneous contrary motions in the heavens -for example, the sun's motion, which moves east to west with a daily motion while simultaneously moving west to east along the ecliptic- within an Aristotelian physical system that assumed that a simple body could have only (...) one proper motion. How medieval natural philosophers resolved this problem is the focus of the article. (shrink)

In this paper I shall examine the philosophical cosmology of medieval Jewish thinkers as developed against the backdrop of their views on time and creation. I shall concentrate upon the Neoplatonic and Aristotelian traditions, with a particular eye to the interweaving of astronomy, cosmology and temporality. This interweaving occurs in part because of the influence of Greek cosmological and astronomical texts upon Jewish philosophers. The tension between astronomy and cosmology is best seen in Maimonides' discussion of creation. Gersonides, on the (...) other hand, is more willing to incorporate astronomical material into his cosmological thinking. By examining these motifs, we shall arrive at a greater understanding of the dimension of temporality within Jewish philosophy. (shrink)

In this paper I shall examine the philosophical cosmology of medieval Jewish thinkers as developed against the backdrop of their views on time and creation. I shall concentrate upon the Neoplatonic and Aristotelian traditions, with a particular eye to the interweaving of astronomy, cosmology and temporality. This interweaving occurs in part because of the influence of Greek cosmological and astronomical texts upon Jewish philosophers. The tension between astronomy and cosmology is best seen in Maimonides' discussion of creation. Gersonides, on the (...) other hand, is more willing to incorporate astronomical material into his cosmological thinking. By examining these motifs, we shall arrive at a greater understanding of the dimension of temporality within Jewish philosophy. (shrink)

This book examines Aristotle's critical reaction to the mathematical cosmology of Plato's Academy, and traces the aporetic method by which he developed his own ...

This is the most noteworthy and, potentially, most fructifying Aristotelian study in recent decades. Unlike many other vues d'ensemble, it is neither a reconstruction of Aristotle's putative "development," nor an analytical rehabilitation of sedimented "doctrines"; rather, Brague's work is an engagement with the original evidence generating and sustaining Aristotle's discourses on the human, the worldly, and the divine. This engagement is carried through in a special register: Aristote et la question du monde is a surrogate for the book on Aristotle (...) Heidegger intended to write and for which Being and Time is the published substitute. The result is not a simplistic transcription of Aristotle into what often passes for Heideggerian jargon, but a thoroughly scholarly and philosophical reading of Aristotle from the "optic" of Being and Time. By examining many of the incises, the parenthetical cuts, into the corpus Aristotelicum, Brague summons our attention to what is important, not only "for Aristotle," but "in Aristotle". (shrink)

This paper offers a detailed account of arguments in De Caelo I by which Aristotle tried to demonstrate the necessity of the perpetual existence and the perpetual rotation of the cosmos. On our interpretation, Aristotle’s arguments are naturalistic. Instead of being based (as many have thought) on rules of logic and language, they depend, we argue, on natural science theories about abilities (δυνάμεις), e.g., to move and to change, which things have by nature and about the conditions under which these (...) abilities can be exercised. Our interpretation locates the De Caelo arguments in the context of some central doctrines of the Organon, the Metaphysics, the Physics, and other texts. The De Caelo arguments fit a number of views developed in these texts. Aristotle’s treatments of local motion, of natural motion and change, of necessity and possibility, and of abilities and their exercises are examples. But, as we interpret them, the De Caelo arguments raise serious questions about the role of (and the need for) Metaphysics A’s soulful Unmoved Mover in Aristotle’s overall natural-scientific picture. (shrink)