Physics (Aristotle)

Physics is next to the metaphysics and the Nicomachean Ethics is one of the major works of Aristotle. It is concerned with the explanation and explanation ( definition) of some basic terms that are used in the description of natural phenomena in daily life. The most important of these are: space, time, movement and cause. This is not a mathematical exposition of the principles of nature in today's sense.

• 3.1 Important editions and translations of Physics
• 3.2 Literature on the physics

Aristotle's method

According to Aristotle many words denote first "undefined a whole" (184 b). The decomposition of the term into its components, is a realization that there the term to its basic building blocks of returns ( cf. Physics I, 1). In the definition of the concepts in question Aristotle goes again remain the same: He considered first a series of proposals defining its predecessors ( Plato and the Presocratics ). It shows that they can not satisfy you, because they bring a number of difficulties and problems ( aporias ) with itself. Then he proposes his own definition. He shows that this avoids the difficulties and that they do the valuable intuitions that was in its attempts to define the predecessor preserved. In Aristotle's own words:

Key terms

Movement

Aristotle meant by movement ( ancient Greek κίνησις Kinesis ) any kind of change. He thus sums up the term in a broader sense than usual today. The movement in this sense can be considered the fundamental concept of physics are considered. With it, Chapters I 7, III 1-3, V 1-2 and book VII, Aristotle defines motion as follows: " The finite - to - reality Come a merely the option under existing insofar as it is just such a - is the movement " (201 a). According to Aristotle 's conception of any change must be created in the possibilities of the changing thing. This system is realized, then it is a change. Aristotle himself gives the following example: "If something can be built, so far we have just what these property from him, comes to its final realization, then it is just built and this is then, building ' " (ibid.).

Nature

According to Aristotle, everything is the " natural procure " what " in itself a beginning of change and enduring" (192 b). Are offset by the things made ​​( artifacts) that are created and received by man through art ( techne τέχνη ), so therefore not have " early in themselves."

Cause

In Chapter II, 3 Aristotle develops the four causes schema:

• Material cause ( material cause ), " resulting in what already exists as something already created something " (194 b). This refers to the material of which it is an object, such as in the case of a silver statue of the metal.
• Formal cause ( causa formalis ): The " shape and the model" (ibid. ) of the object, in the case of the statue of the figure of a horse.
• Efficient cause ( causa efficientis ): " where the initial impetus for change or persistence comes " (ibid.). This would be the example of the statue of the sculptor.
• Final cause ( causa finalis ): "the goal, that is, the Wherefore " (ibid.). The purpose of the statue is that it decorates the room.

According to today's language we would really only the efficient cause designate as the cause. The four causes of Aristotle may be considered as four different patterns of explanation, the answer why a certain thing exists in its particular character.

Accident

With the definition of chance and coincidence to Physics II 4-9 deals. Aristotle's definition of random is: " When in the field of events that occur in the strict sense because of something and its cause is beyond them, something happens that can not be reconciled with the result in a why - relationship, then we call it, by chance. '" (197 b). His example is this: A horse escapes the fact that it comes out of the stall, a misfortune, but it is not come out because it wanted to escape the disaster ( it did not know of the impending disaster ). In this case, one would say: " The horse is accidentally come out ." The cause here is coming out, the result is that it escapes the disaster, and between the two there is no " why " relationship ( the horse has not come out to escape the disaster ), therefore the entire accidental.

An interesting passage is found in 198 b: Aristotle seems here Empedocles many centuries before Charles Darwin attributed to a first theory of evolution, which contains ("[ ... ] the elements of the mutation and selection as these entities, who happened to be in suitable received which may be met. Where it is not revealed so as they went on [ ... ] "). This theory is rejected by Aristotle.

Infinity

This term deal Chapters III 4-8. Aristotle distinguishes in terms of division ( Division ) and on "Add translation " (addition ) between an infinity. He explains the term as follows: " It follows so that unlimited ' means the opposite of what one says this: Not what has nothing outside of his ', but what there is always an appearance ', which is unlimited. " (207 a). By its definition Aristotle opposes the idea of ​​a so-called actual infinity, that is, against the idea that there exists something infinitely large, which is present as a whole. According to him, there are only so-called potential infinities, ie quantities for which again is another element can be added. However, these are never fully present.

Place or room

Aristotle does not handle the space in the modern sense, but discussed in IV 1-5 the place. His definition of the spatial concept is: "The immediate, immovable boundary of the Comprehensive - this is place" ( 212 a). The idea here is that the location of a body - such as a table - " directly includes " as a very precisely fitting glove hand. In contrast to the glove but the place is " immobile ", the table is i.e. worn away, his place is not moved, but the table comes to a different location.

Emptiness

The concept of emptiness deal Chapters IV 6-9. Aristotle argued here that there can be no void ( cf. horror vacui ), where he referred to as " empty" a place " where nothing is " (213 b). This argument was refuted seemingly 1647 Blaise Pascal with experiment emptiness of emptiness. Modern physics favors Aristotle's conception. There is no nothing, because space is spanned only by the general theory of relativity, gravitational fields. For quantum- mechanical point of view are everywhere vacuum fluctuations.

Time

Aristotle's remarks on time can be found in IV 10-14. He defines time as "the number of motion in terms of, before 'and' after ' " (219 b ), and that number in the sense of a divisible size. The rationale is that we (eg the growth of a plant ) measure changes based on other changes quantitatively. In this second change is uniform displacements (now the movement of clock hands, formerly the apparent movement of the sun). In this respect we can there a before and an after make up, this is then transferred to temporal sequences.

It should be noted here that Aristotle considers the concept of change as fundamental and the notion of time based on certain changes, namely uniform changes in location constructed. According to the modern view, the fundamental concept of time and the concept of motion is inversely derived from it.

Continuity

In Chapter V, 3 and in Book VI of Aristotle explains terms such as connected ( things, " whose edges form a unit "; 231 b), in contact ( " whose edges are together ", ibid ), in order ( " where nothing Congener between them is ", ibid ) and other relevant in this context expressions. These definitions serve him to deal with the atomism ( Democritus ) and atomistic conceptions of time. Both theories rejects Aristotle. He is concerned in this context with a refutation of the paradoxes of Zeno of Elea.

The unmoved mover

In the last book of physics (Book VIII), and ahead of his theology (Book XII ) argues Aristotle for the need for an " unmoved mover ", that is, a force that causes all movement in the world. This theory inspired Thomas Aquinas later to his so-called cosmological proof of God.