The unmoved mover (Ancient Greek : ὃ οὐ κινούμενον κινεῖ, romanized: ho ou kinoúmenon kineî, lit. 'that which moves without being moved') or prime mover (Latin : primum movens) is a concept advanced by Aristotle as a primary cause (or first uncaused cause) or "mover" of all the motion in the universe. As is implicit in the name, the unmoved mover moves other things, but is not itself moved by any prior action. In Book 12 (Greek : Λ) of his Metaphysics , Aristotle describes the unmoved mover as being perfectly beautiful, indivisible, and contemplating only the perfect contemplation: self-contemplation. He equates this concept also with the active intellect. This Aristotelian concept had its roots in cosmological speculations of the earliest Greek pre-Socratic philosophers and became highly influential and widely drawn upon in medieval philosophy and theology. St. Thomas Aquinas, for example, elaborated on the unmoved mover in the Quinque viae .
Aristotle argues, in Book 8 of the Physics and Book 12 of the Metaphysics , "that there must be an immortal, unchanging being, ultimately responsible for all wholeness and orderliness in the sensible world".
In the Physics (VIII 4–6) Aristotle finds "surprising difficulties" explaining even commonplace change, and in support of his approach of explanation by four causes, he required "a fair bit of technical machinery". πρῶτον κινοῦν ἀκίνητον: an independent divine eternal unchanging immaterial substance.This "machinery" includes potentiality and actuality, hylomorphism, the theory of categories, and "an audacious and intriguing argument, that the bare existence of change requires the postulation of a first cause, an unmoved mover whose necessary existence underpins the ceaseless activity of the world of motion". Aristotle's "first philosophy", or Metaphysics ("after the Physics"), develops his peculiar theology of the prime mover, as
Aristotle adopted the geometrical model of Eudoxus of Cnidus, to provide a general explanation of the apparent wandering of the classical planets arising from uniform circular motions of celestial spheres.While the number of spheres in the model itself was subject to change (47 or 55), Aristotle's account of aether, and of potentiality and actuality, required an individual unmoved mover for each sphere.
Simplicius argues that the first unmoved mover is a cause not only in the sense of being a final cause—which everyone in his day, as in ours, would accept—but also in the sense of being an efficient cause (1360. 24ff.), and his master Ammonius wrote a whole book defending the thesis (ibid. 1363. 8–10). Simplicius's arguments include citations of Plato's views in the Timaeus—evidence not relevant to the debate unless one happens to believe in the essential harmony of Plato and Aristotle—and inferences from approving remarks which Aristotle makes about the role of Nous in Anaxagoras, which require a good deal of reading between the lines. But he does point out rightly that the unmoved mover fits the definition of an efficient cause—"whence the first source of change or rest" (Phys. II. 3, 194b29–30; Simpl. 1361. 12ff.). The examples which Aristotle adduces do not obviously suggest an application to the first unmoved mover, and it is at least possible that Aristotle originated his fourfold distinction without reference to such an entity. But the real question is whether, given his definition of the efficient cause, it includes the unmoved mover willy-nilly. One curious fact remains: that Aristotle never acknowledges the alleged fact that the unmoved mover is an efficient cause (a problem of which Simplicius is well aware: 1363. 12–14)...— D. W. Graham, Physics
Despite their apparent function in the celestial model, the unmoved movers were a final cause, not an efficient cause for the movement of the spheres;they were solely a constant inspiration, and even if taken for an efficient cause precisely due to being a final cause, the nature of the explanation is purely teleological.
The unmoved movers, if they were anywhere, were said to fill the outer void, beyond the sphere of fixed stars:
It is clear then that there is neither place, nor void, nor time, outside the heaven. Hence whatever is there, is of such a nature as not to occupy any place, nor does time age it; nor is there any change in any of the things which lie beyond the outermost motion; they continue through their entire duration unalterable and unmodified, living the best and most self sufficient of lives… From [the fulfilment of the whole heaven] derive the being and life which other things, some more or less articulately but other feebly, enjoy."— Aristotle, De Caelo, I.9, 279 a17–30
The unmoved movers are, themselves, immaterial substance, (separate and individual beings), having neither parts nor magnitude. As such, it would be physically impossible for them to move material objects of any size by pushing, pulling or collision. Because matter is, for Aristotle, a substratum in which a potential to change can be actualized, any and all potentiality must be actualized in a being that is eternal but it must not be still, because continuous activity is essential for all forms of life. This immaterial form of activity must be intellectual in nature and it cannot be contingent upon sensory perception if it is to remain uniform; therefore eternal substance must think only of thinking itself and exist outside the starry sphere, where even the notion of place is undefined for Aristotle. Their influence on lesser beings is purely the result of an "aspiration or desire",and each aetheric celestial sphere emulates one of the unmoved movers, as best it can, by uniform circular motion. The first heaven, the outmost sphere of fixed stars, is moved by a desire to emulate the prime mover (first cause), in relation to whom, the subordinate movers suffer an accidental dependency.
Many of Aristotle's contemporaries complained that oblivious, powerless gods are unsatisfactory.Nonetheless, it was a life which Aristotle enthusiastically endorsed as one most enviable and perfect, the unembellished basis of theology. As the whole of nature depends on the inspiration of the eternal unmoved movers, Aristotle was concerned to establish the metaphysical necessity of the perpetual motions of the heavens. It is through the seasonal action of the Sun upon the terrestrial spheres, that the cycles of generation and corruption give rise to all natural motion as efficient cause. The intellect, nous , "or whatever else it be that is thought to rule and lead us by nature, and to have cognizance of what is noble and divine" is the highest activity, according to Aristotle (contemplation or speculative thinking, theōrētikē). It is also the most sustainable, pleasant, self-sufficient activity; something which is aimed at for its own sake. (In contrast to politics and warfare, it does not involve doing things we'd rather not do, but rather something we do at our leisure.) This aim is not strictly human, to achieve it means to live in accordance not with mortal thoughts, but something immortal and divine which is within humans. According to Aristotle, contemplation is the only type of happy activity which it would not be ridiculous to imagine the gods having. In Aristotle's psychology and biology, the intellect is the soul, (see also eudaimonia ).
In book VIII of his Physics,Aristotle examines the notions of change or motion, and attempts to show by a challenging argument, that the mere supposition of a 'before' and an 'after', requires a first principle. He argues that in the beginning, if the cosmos had come to be, its first motion would lack an antecedent state, and as Parmenides said, "nothing comes from nothing". The cosmological argument, later attributed to Aristotle, thereby draws the conclusion that God exists. However, if the cosmos had a beginning, Aristotle argued, it would require an efficient first cause, a notion that Aristotle took to demonstrate a critical flaw.
But it is a wrong assumption to suppose universally that we have an adequate first principle in virtue of the fact that something always is so … Thus Democritus reduces the causes that explain nature to the fact that things happened in the past in the same way as they happen now: but he does not think fit to seek for a first principle to explain this 'always' … Let this conclude what we have to say in support of our contention that there never was a time when there was not motion, and never will be a time when there will not be motion. (Physics VIII, 2)
The purpose of Aristotle's cosmological argument, that at least one eternal unmoved mover must exist, is to support everyday change.
Of things that exist, substances are the first. But if substances can, then all things can perish... and yet, time and change cannot. Now, the only continuous change is that of place, and the only continuous change of place is circular motion. Therefore, there must be an eternal circular motion and this is confirmed by the fixed stars which are moved by the eternal actual substance that's purely actual.
In Aristotle's estimation, an explanation without the temporal actuality and potentiality of an infinite locomotive chain is required for an eternal cosmos with neither beginning nor end: an unmoved eternal substance for whom the Primum Mobileturns diurnally and whereby all terrestrial cycles are driven: day and night, the seasons of the year, the transformation of the elements, and the nature of plants and animals.
Aristotle begins by describing substance, of which he says there are three types: the sensible, which is subdivided into the perishable, which belongs to physics, and the eternal, which belongs to "another science". He notes that sensible substance is changeable and that there are several types of change, including quality and quantity, generation and destruction, increase and diminution, alteration, and motion. Change occurs when one given state becomes something contrary to it: that is to say, what exists potentially comes to exist actually. (See Potentiality and actuality.) Therefore, "a thing [can come to be], incidentally, out of that which is not, [and] also all things come to be out of that which is, but is potentially, and is not actually." That by which something is changed is the mover, that which is changed is the matter, and that into which it is changed is the form.
Substance is necessarily composed of different elements. The proof for this is that there are things which are different from each other and that all things are composed of elements. Since elements combine to form composite substances, and because these substances differ from each other, there must be different elements: in other words, "b or a cannot be the same as ba".
Near the end of Metaphysics, Book Λ, Aristotle introduces a surprising question, asking "whether we have to suppose one such [mover] or more than one, and if the latter, how many". Aristotle concludes that the number of all the movers equals the number of separate movements, and we can determine these by considering the mathematical science most akin to philosophy, i.e., astronomy. Although the mathematicians differ on the number of movements, Aristotle considers that the number of celestial spheres would be 47 or 55. Nonetheless, he concludes his Metaphysics, Book Λ, with a quotation from the Iliad : "The rule of many is not good; one ruler let there be."
In Metaphysics 12.8, Aristotle opts for both the uniqueness and the plurality of the unmoved celestial movers. Each celestial sphere possesses the unmoved mover of its own—presumably as the object of its striving, see Metaphysics 12.6—whereas the mover of the outermost celestial sphere, which carries with its diurnal rotation the fixed stars, being the first of the series of unmoved movers also guarantees the unity and uniqueness of the universe.
The universe has no beginning in time, no temporal first cause, so Aristotle is obviously not seeking an efficient cause in the sense of "what set it all off?" Aristotle's unmoved mover acts as final cause, as the good toward which all things strive. That is, it acts an objects of desire: "The object of desire and the object of thought move without being moved" (Met., 1072a26–27).
Aristotle was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Lyceum, the Peripatetic school of philosophy, and the Aristotelian tradition. His writings cover many subjects. including physics, biology, zoology, metaphysics, logic, ethics, esthetics, poetry, theatre, music, rhetoric, psychology, linguistics, economics, politics, and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him. It was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique influence on almost every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion.
A cosmological argument, in natural theology and natural philosophy, is an argument in which the existence of God is inferred from alleged facts concerning causation, explanation, change, motion, contingency, dependency, or finitude with respect to the universe or some totality of objects. It is traditionally known as an argument from universal causation, an argument from first cause, or the causal argument.. Whichever term is employed, there are three basic variants of the argument, each with subtle yet important distinctions: the arguments from in causa (causality), in esse (essentiality), and in fieri (becoming).
Substance theory, or substance–attribute theory, is an ontological theory about objecthood positing that a substance is distinct from its properties. A thing-in-itself is a property-bearer that must be distinguished from the properties it bears. The corresponding concept in Eastern philosophy is svabhava.
Hylomorphism is a philosophical theory developed by Aristotle, which conceives being (ousia) as a compound of matter and form. The word is a 19th-century term formed from the Greek words ὕλη hyle, "wood, matter", and μορφή, morphē, "form".
Aristotelian theology and the scholastic view of God have been influential in Western intellectual history.
Natural philosophy or philosophy of nature was the philosophical study of nature and the physical universe that was dominant before the development of modern science. It is considered to be the precursor of natural science.
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmological models developed by Plato, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the apparent motions of the fixed stars and planets are accounted for by treating them as embedded in rotating spheres made of an aetherial, transparent fifth element (quintessence), like jewels set in orbs. Since it was believed that the fixed stars did not change their positions relative to one another, it was argued that they must be on the surface of a single starry sphere.
The Peripatetic school was a school of philosophy in Ancient Greece. Its teachings derived from its founder, Aristotle, and peripatetic is an adjective ascribed to his followers.
On the Heavens is Aristotle's chief cosmological treatise: written in 350 BC it contains his astronomical theory and his ideas on the concrete workings of the terrestrial world. It should not be confused with the spurious work On the Universe.
The Physics is a named text, written in ancient Greek, collated from a collection of surviving manuscripts known as the Corpus Aristotelicum, attributed to the 4th-century BC philosopher Aristotle.
In philosophy, potentiality and actuality are a pair of closely connected principles which Aristotle used to analyze motion, causality, ethics, and physiology in his Physics, Metaphysics, Nicomachean Ethics and De Anima, which is about the human psyche.
Metaphysics is one of the principal works of Aristotle and the first major work of the branch of philosophy with the same name. The principal subject is "being qua being," or being insofar as it is being. It examines what can be asserted about any being insofar as it is and not because of any special qualities it has. Also covered are different kinds of causation, form and matter, the existence of mathematical objects, and a prime-mover God.
The Quinque viæ are five logical arguments regarding the existence of God summarized by the 13th-century Catholic philosopher and theologian St. Thomas Aquinas in his book Summa Theologica. They are:
Incorporeality is "the state or quality of being incorporeal or bodiless; immateriality; incorporealism." Incorporeal means "Not composed of matter; having no material existence."
The "four causes" are elements of an influential principle in Aristotelian thought whereby explanations of change or movement are classified into four fundamental types of answer to the question "why?". Aristotle wrote that "we do not have knowledge of a thing until we have grasped its why, that is to say, its cause." While there are cases where identifying a "cause" is difficult, or in which "causes" might merge, Aristotle held that his four "causes" provided an analytical scheme of general applicability.
Aristotelian physics is the form of natural science described in the works of the Greek philosopher Aristotle (384–322 BCE). In his work Physics, Aristotle intended to establish general principles of change that govern all natural bodies, both living and inanimate, celestial and terrestrial – including all motion, quantitative change, qualitative change, and substantial change. To Aristotle, "physics" was a broad field that included subjects that would now be called the philosophy of mind, sensory experience, memory, anatomy and biology. It constitutes the foundation of the thought underlying many of his works.
The natural sciences saw various advancements during the Golden Age of Islam, adding a number of innovations to the Transmission of the Classics. During this period, Islamic theology was encouraging of thinkers to find knowledge. Thinkers from this period included Al-Farabi, Abu Bishr Matta, Ibn Sina, al-Hassan Ibn al-Haytham and Ibn Bajjah. These works and the important commentaries on them were the wellspring of science during the medieval period. They were translated into Arabic, the lingua franca of this period.
Ancient, medieval and Renaissance astronomers and philosophers developed many different theories about the dynamics of the celestial spheres. They explained the motions of the various nested spheres in terms of the materials of which they were made, external movers such as celestial intelligences, and internal movers such as motive souls or impressed forces. Most of these models were qualitative, although a few of them incorporated quantitative analyses that related speed, motive force and resistance.
The question of the eternity of the world was a concern for both ancient philosophers and the medieval theologians and philosophers of the 13th century. The question is whether the world has a beginning in time, or whether it has existed from eternity. The problem became a focus of a dispute in the 13th century, when some of the works of Aristotle, who believed in the eternity of the world, were rediscovered in the Latin West. This view conflicted with the view of the Catholic Church that the world had a beginning in time. The Aristotelian view was prohibited in the Condemnations of 1210–1277.
Philosophy of motion is a branch of philosophy concerned with exploring questions on the existence and nature of motion. The central questions of this study concern the epistemology and ontology of motion, whether motion exists as we perceive it, what is it, and, if it exists, how does it occur. The philosophy of motion is important in the study of theories of change in natural systems and is closely connected to studies of space and time in philosophy.