Instructor: Dr. Bob Zunjic
PHL 321




An Outline

The Physics  of Aristotle is a series of lecture notes collected by later editors (Aristotle himself did not publish it as a separate book). It gives a general introduction to the study of nature conceived as the sum total of material objects that are subject to various types of change. Hence its range is much larger than the subject matter of modern physics which deals only with motion in space. In contrast to modern (Cartesian) physics, which is quantitative  (mathematical), Aristotle's physics is rather qualitative for it studies growth and alteration as well. Physical investigation proceeds in the fashion of "second philosophy", i.e. as a theoretical (logical and dialectical) examination of principles and elements. The exposition is divided into eight books most of which deal with some aspects of movement: change, causation, place, time, void, continuity, infinity, contact etc. In Book A Aristotle tries to conceptualize change and its principles, while in book B he first determines what kind of things fall within the scope of natural science and what is their nature. Then he launches a discussion of the so called four "causes" appending to it his own theory of chance and natural teleology. Some formulations indicate that these lectures have served as a kind of introductory course in Aristotle's philosophy, perhaps while he was still in the Academy.

Book I (The Principles of Change)


The Greek title ta physika (akroamata) denotes "(lectures) on nature".


For Aristotle, nature (physis) includes not only living beings but all physical things (stones, elements, celestial bodies) so far as they are:
(a) subject to change
(b) inseparable from matter
(c) set in motion by themselves

Note: The study of physical things, as practiced by Aristotle, obviously stretches over the realm of both modern physics and biology and includes also what would be today the subjet matter of chemistry, optics, mineralogy and astronomy. However, Aristotle's approach is purely philosophical, not empirical.

Method: Aristotle examines "common concepts" about physical things dialectically in order to find out the correct account of change in its different dimensions.
Physical Cognition: The science of nature looks for first principles, causes and elements of the visible world (everything what is there = being). To achieve knowledge means to be cognizant of the most basic (original and ultimate) constituents (principles and elements) of something. Things that do not possess principles and elements (simples or amorphous things) cannot be the subject of knowledge. (Ever since Aristotle "scientific knowledge" is conceived as the knowledge about causes.)

Philosophical Lexicon

Being (Greek: to on) = This substantive is derived from the verb "to be" and represents the most general term for whatever occurs as the subject of language or thought; it denotes everything that exists, all that is. Consequently, do not limit its meaning to living beings, only!

Principle (Greek: arche) = The source of something, the determining beginning, the defining origin.

Cause (Greek: aition) = That which is responsible (literally: "blameworthy") for changing something else or setting it into motion; a reason which accounts for something else.

Elements (Latin: elementa) = The simple constituents of a complex.

Methodological Remarks

Ch. 1, Point of Departure: The logical starting point in this study would be that what is "more knowable". But this expression is ambiguous, for it could mean (1) more knowable (and more perspicuous) to us or (2) more knowable (and perspicuous) in itself (by nature, without qualification). Aristotle suggests to start with (1) and then to advance toward (2).
Note: This is different from what Aristotle says in the Posterior Analytic (I, 2), where he starts from what is more knowlable in itself, but W. Ross is right in pointing to the different character of these inquiries (An. Post. deals with scientific proof).
Perspicuity: We are more familiar with inarticulate wholes (trees, animals, houses) than with their elements and principles that are not immediately visible. For instance, we see trees rather than their branches or leaves.
Sequence: Thus it makes sense to start with "inarticulate wholes" and then to proceed to examine their components. Since the wholes are a kind of the universal, it is permissible to say that the physical study must start from the universal and then move to particulars.
  Note: Aristotle says in fact that "we must advance from universals to particulars", which is opposed to what he usually claims: the ontological and cognitive primacy of the individual over the universal that is farthes away from the senses (Posterior Analytic, 72a4). The only explanation for this discrepancy is that Aristotle takes here the universal in a different sense, as a non-specified whole. He truly says that "the universal is a sort of whole" ("general account"); the analogy would hold anyway because the universal covers many parts as does the whole.
Parallel: A name is to a whole what is a definition to a specified particular (thing). Therefore, one should start with names (as with signified wholes) and then seek to articulate the properties of the named thing the way a definition does.
Note: For Aristotle, a definition typically breaks down a whole into genus and differentia, but here what is meant is rather a division into species of properties. W. Ross claims that for the illustration to be valid one needs to take "the particular(s)" as denoting various meanings of a word.

Contraries and the Subject

Ch. 5, Regularity: Nothing acts or is affected in just any old way by the agency of just any old thing, unless coincidentally. Coming to be is also determined and regulated, not arbitrary and whimsical. In other words, miracoulous and unorderly generations in the style of Empedocles, Anaxagoras or later alchemy (everything from anything) are not possible. The processes of coming to be and passing away are regulated.
Question 1: What is the basis of this regularity?
Contraries: Everything that comes to be or perishes does so from one contrary into the other, or from or into the intermediate.
Horizontal Contraries:

Something pale can come to be only from something non-pale, not from anything else, like "being musical". This is both an ontological and logical necessity.
But "what is not-pale", although a correct logical designation for the source of something pale, is too broad and unspecific ontologically, for the "not-pale" could be anything, and something pale cannot emerge from anything. Therefore the right designation for the state from which the pale emerges is its contrary: something dark. (The dark is narrower than the not-pale.)
The same holds true of something musical, which comes to be from the not-musical itself being specified as un-musical (or not yet musical). ("Musical" is here taken in the sense of being educated in general including being knowledgeable about music or being trained to play an instrument.)
However, if the dark is a person who happens to be musical as well, we can say that the pale has come to be from the musical (person) coincidentally.
Passing away (perishing) is regulated in the same (reversed) way.

Vertical Arrangement: Composites come to be from the simples that make up their ingredients (for instance house is built from the bricks). Sometimes it is difficult to accomodate this relation into a relation between the opposites becuase not always each opposite has its specific name. Generally speaking, however, the relation between the composites and the simples could be represented as one between opposites only if we view it as a path from disorder to order (and conversely) both extremes specified accordingly.
Synonymy: Order is understood synonymously with arrangement or combination.
Ground: Everything that comes to be (or perishes) comes to be (or perishes) from one contrary into the other, or from or into the intermediate. The intermediates themselves are form the contraries (for instance, colors come to be from white and black). If so, then everything comes to be either from contraries or is itself a contrary.
Conclusion: Contraries are then principles of all natural coming to be.
Ch. 6, Third Factor: This would be a hasty conclusion. The contraries themselves require some other nature as subject. we must suppose such a nature, or we are faced with an aporia (impass): How could a non-substance (a contrary) be prior to a substance?
Argument: Contraries do not exist as independent entities - they are not "the substance of anything". They are in fact always predicated as properties of a subject. If they were principles this would never be possible. For how a principle could be conditioned upon something else preceding the principle? This would simply disqualify the principle as a principle.
Therefore contraries are not the principles. Furthermore, they are not substances, for a substance does not allow a contrary (a man is not a contrary to a horse, or a dog to a sculpture). Hence, there must be something else preceding contraries which is the subject of contraries.
Underlying Stuff: If coming to be and passing away are regulated and if contraries are dependent attributes we must assume a third thing as the subject of change. Those earlier thinkers (Milesians) who have posited "one nature" of the whole universe were basically right, particularly when they conceived that nature as something "intermediate" between the elements. More determinate natures like fire, earth and air are essentially contraries and cannot play the role of subject for different opposites (hot - cold, dry - wett, etc.).

Philosophical Lexicon

Opposites (Latin: oppositus) = the most general relation of different properties (for instance, black versus yellow).

Contraries (Latin: contrarius) = the more specific relation between two properties that are logically opposed (like black and white). They cannot be both ascribed at the same time, but they can be both denied of the same subject.

Contradiction (Latin: contradicere) = the most strict relation between two properties that exclude each other (for instance: black and not-black). They cannot be both true or both false.

Coincidentally = occuring with something else at the same time and in the same place (or in the same subject) without being logically or necessarilly connected with it.

Substance (Latin: substantia) = a separate entity that exists on its own and upon which everything else depends for its existence; that of which something (a quality, attribute, relation) may be affirmed or denied; that what a thing is to be, its nature.

Subject (Latin: subjectum) = the underlying ground, that in which something can be said to inhere (substratum).

Property (Latin: proprium) = that which is proper to a thing (characteristic or feature, attribute); unlike substances and individual entities a property can be shared by many different things; but properties cannot exist by themselves, independently.

Account of Coming to Be

Ch. 7, Natural Procedure: Aristotle suggests to discuss first what is common to every case of coming to be and then to study special features.
Three Ways of Saying: (1) "A man comes to be musical."
(2) "The not-musical thing comes to be musical."
(3) "The not-musical man comes to be a musical man."
Three Aspects:

(i) "Simple thing coming to be F" (1 and 2).
(ii) "Simple thing that comes into being" (= the musical thing).
(iii) "Compound" (= both the thing that comes into being and what comes to be that thing) = (3).

Compositional Division:
Coming To Be Something

Simple Things

Compound Things

(a) A man comes to be musical.
(b) The not-musical thing comes to be musical.

(c) The not-musical man comes to be a musical man.

Different Poles: (I) The thing that comes into being (F).
(II) What comes to be that thing (G).
Different Stretch: (1) Something comes to be F.
(2) Something comes to be F from being G.
Specification: We can say both (1) and (2) for simple things (a) and (b). For (c) we can say (2) only if a man comes to be musical from being not-musical. But we do not say that man comes to be musical from being man because this becoming pertains only to an accidental property, not to an essential (substantial) property like being a man. When a man becomes musical he takes on a new quality without changing the subject.
Core Preserved: Sometimes G remains preserved in F, sometimes not.
Remainder: When something comes to be F it remains that something it was (G) if it is the subject, but not if it was just an opposite property.
Subject: If something which comes to be is a subject, it remains despite the change it undergoes. (For instance, a man remains a man when he becomes musical from being not-musical.) He is numerically one but "aspectually" two or more.
Property: If something is a property (the not-musical, or simply the unmusical) it does not remain after the change took place but turns into its contrary. When G does not remain we do not say that G comes to be F. We say this only for a subject.
A man comes to be musical from being not-musical, not the unmusical comes to be musical from being a man. The way of speaking indicates deeper logical and ontological differences. "Being a man is not the same as being an unmusical thing".
Compound: The initial compound "the unmusical man" also vanishes.
Matter - Subject: When a matter is subject we do not say that it comes to be F even if it remains, because it is indefinite. We do not say that the bronze (G) comes to be a statue (F), but a statue comes to be from bronze.


In regard to We say We do not say
Subject A man comes to be musical from being not-musical. A man comes to be musical from being a man.
Property The not-musical comes to be musical. The unmusical comes to be musical from a man.
Compound The musical man comes to be musical from being an unmusical man or an unmusical man comes to be musical. The musical man comes to be musical from what is musical.
Artefact A statue comes to be from bronze. The bronze comes to be a statue.


Both Ways:

If something comes to be from being G, where G is opposite to F and G does not remain, we can say both that something comes to be F from being G and that G comes to be F (a man comes to be musical from being unmusical and the unmusical man comes to be musical).

Substantial Generation: Only substances come to be as such (without qualification, not becoming something).
Formal Duplicity: In every case there must be some subject that comes to be something.
Categorial Division:  


Coming to be

Coming to be simply

Coming to be something

Substance comes to be without qualification

Some subject comes to be something.

How a subject comes to be?

A subject comes to be according to the table of categories.
(1) Becoming a certain quantity.
(2) Becoming a certain quality.
(3) Becoming relative to something.
(4) Becoming somewhere (place).
Aristotle mentions only four of categories (some manuscripts have also "when" - time) but this incompletness does not affect the argument.

How substances come to be?

Substances also come to be from some subject. (For instance, plants and animals come to be from seed.)
(1) By change of figure (a statue).
(2) By addition (growing beings).
(3) By subtraction (Hermes from the stone).
(4) By composition (house).
(5) By alteration (hair becoming gray).

Generally Speaking:
What comes to be is composite, consisting of something that comes into being and something that comes to be this, which is either the subject or the opposite.

Components of Coming To Be

What comes to be is composite:
(F) Something that comes into being.
(G) Something that comes to be this.
Musical man
Unmusical man
(Man + musical)
(Man lacking musicality)
  Something that comes to be:  
The subject
The opposite

The unmusical

The Number of Principles


If natural things come to be from their principles and causes according to their essence and not coincidentally, then everything (in nature) comes to be from the subject and the shape. (matter and form)

Counting: The subject is one in number (or matter) but two in form (man and unmusical man). It is one in number (in reality) but not in form (in account). There are two accounts: (a) Being a man and (b) Being an unmusical thing. The two are not the same, for a man did not become a musical man from being a man.
Thisness: Matter in general is a "this" more than the privation.
Privation: Privation is a non-existent form or the form existing by virtue of its absence. In this sense it is a coincident (goes coincidentally with the form).
Oneness: Form is one in itself. But one subject could be said in many ways at the same time with regard to its manifold aspects.

(a) In one way there are two principles of change - the contraries: the musical and the unmusical, the hot and the cold, the ordered and the disordered. This only if we conceive these opposites as entities and not mere properties.


Puzzle: How coming to be is possible from contraries if they cannot affect each other? How the unmusical can become the musical? This is not possible if they are the only components of the ongoing transformation.
Solution: Thus there must be something in between, which is not a contrary itself. At the begining we had two: Being man and being unmusical. These are categorially disparate formulae, of which the second clearly entails its contrary. Therefore only the first is the underlying subject which undergoes the transition from one contrary to another.
Triplicity: Since the contraries are "different in being" from the subject we reach a different conclusion:
(b) In another way, there are three principles of change: two contraries and the subject (being unmusical, being musical and being a man).
Analogy: Subject is different in different areas, but its identity is established by analogy. Subject itself stand in the same analogy with substance (a this and a being).


Substance (a this, a being)

1st Principle: (1) The subject comes first, but it is not one (it is a multitude in itself) nor is it a being or a "this" in the way substance is (that is to say, it is rather matter and therefore cannot exist independently).
2nd Principle: (2) Another principle is the one specified by the account (form).
3rd Principle:
(3) Third principle is the contrary of the second, namely the privation.

Question 2:

What is more of a substance: the subject or the form?
Aristotle produces three proofs in B1 to demonstrate that the palm should go to form. (In Zeta book of the Metaphysics he considers a third candidate as well: the unity of the two, the compound.)

The Impasses of the Presocratics

Ch. 8, Puzzle: How things can come to be and pass away? Where do they come from? Where do they go? Those were the questions raised by the Presocratics. Aristotle now dicusses their answers to show that they do not solve the puzzle.

The Eleatics were the first to explore the problem philosophically (i.e. logically as opposed to physically). But they were led astray by the lack of experience (the knowledge of nature).

Thesis: Nothing that is either comes to be or perishes.
Argument: What comes to be must come to be either from what is or from what is not, but what is cannot come to be (since it already is), while nothing can come from what is not (since there must be some subject for change).
This is a pretty good summary of Parmenides' argument as it is preserved in B VIII, 5-20.
Consequence: The Eleatics did away with all coming to be (no change).
The Worst: Not only did they deny motion and chaneg. To make things worse they concluded that there is no plurality, only one being frozen in time (being itself = what already is).
Response: Aristotle undertakes a rebuttal of the Eleatic argument by introducing a distinction between coming to be out of nothing in absolute sense and coming to be from nothing in qualified sense.
Parallels: The claim "that something comes to be from what is or from what is not" or "comes to be anything whatever" is in a sense no different from the claim that "a doctor is or comes to be something from being a doctor". By the same token, the claim "that what is or what is not acts on something or is acted on" finds its counterpart in the claim "that a doctor acts on something or is acted on".
Illumination: Aristotle wants to show that the question whether something could be generated from something else or from not-something could be made simpler by regarding a doctor as that "something". If a doctor exists, it is understandable that he can move, can act upon, can generate something, or can undergo himself certain change.
Distinction: A doctor can act or be acted upon in two senses: (a) as a doctor (intrinsically) or (b) in another capacity (coincidentally). He practices medicine or acquires medical knowledge insofar as he is a doctor, but he builds a house as a housebuilder and becomes pale insofar as he is a dark person. Similarly, he can be acted on in the capacity of being a doctor (a) or in another (coincidental) capacity (b). But in neither case does a doctor come to be this or that from nothing nor does he produce something from nothing or vanishes into nothing.
Qualified Sense: Consequently, coming to be from what is not does not signify coming to be from what is absolutely not (not-being, nothingness), but rather from it insofar as it is not (in a certain sense). By the rule, change occurs by qualification (coincidentally), not absolutely as impossible and miraculous coming to be out of nothing. What is comes to being coincidentally from what is as a matter, which is a kind of privation, or possesses a privation which makes it a not-being.
Answer: The early philosophers did not make this decisive distinction between coming to be totally out of not-being and coming to be obliquely from not-being in the sense of privation and so they erroneously concluded that nothing else could exist ("is") besides what already is.
Axiom: Aristotle accepts the principle that nothing comes to be without qualification from what is not. In other words, coming to be from what is not simply is not possible (the principle: ex nihilo nihil fit). But he shows how things can come from what is not coincidentally.
Correction: For instance, something could come from the privation, which in itself is not-existent and does not belong strictly to the thing when it has come to be. But it is a privation on the subject of something as related to something else (for instance, the unmusical is the privation of the musical, and thus an unmusical man can become musical from being unmusical).
Question: How it is possible that something comes to be from the privation?
Coincidentally: Strictly speaking there is no coming to be from what is or of what is. But that what is comes also to be coincidentally. This includes the generation of animal from animal (generic coming to be) and the coming to be of a certain animal from a certain animal (particular coming to be).
Transsubstantial Change: Aristotle claims that coming to be of something from something is not more problematic than ordinary generation of animals. An animal is born from a particular animal and from an animal (as such), but it is not totally identical with its progenitor.
For the sake of argument Aristotle suggests to suppose that a dog came to be from a horse (to illustrate two aspects of coincidental coming to be). Assuming that this manuscript variant is not a sheer corruption of the text (as ross suspects), the dog would come to be not only from a certain animal of a particular kind, but also coincidentally from animal (in general). However, the dog would not come to be an animal as an animal, because it was already an animal in the previous stage (as horse). Whenever the source of coming to be is not specified, it is coincidental, for a dog strictly speaking does not come from animal in general or even an animal insofar as it is animal (it is already present) but from a dog. By the same token nothing comes from what it is in general but from its specific components, aspects and features, not insofar as they are just beings and simply beings.
Contradiction: In correcting Parmenides Aristotle does not want to side with Heraclitus. Coming to be from what is not insofar as it is not does not do away the principle "everything is or is not". Against Heraclitus, Aristotle maintains the principle of non-contradiction despite his claim that things come to be although not from nothing. He gets around the difficulty of accepting two disparate claims by distinguishing between coming to be in absolute sense and coming to be in qualified sense (essential and coincidental coming to be).

The Mistakes of the Academy

Ch. 9, Potentiality:

Another way of solving the puzzle of change is to introduce the distinction between potentiality and actuality. What actually is could potentially not be (be not), and the other way round. Something could be many things in many different respects potentially. It is therefore mistaken to think that if a thing is actually one in number (numerically) it is also one potentially.
Note: The concepts of potentiality and actuality are discussed extensively in book Theta of the Metaphysics.

Parallelism: A thing which is actually one is one in number with regard to its matter. And even though the matter could be potentially something else, its mode of existence is not the same as in the privation which indicates the absence of the form. The matter is a not-being coincidentally (being in a way substance, namely as subject), while the privation is a not-being on its own (simply).
The Great and the Small: Previous thinkers identified "the great and the small" with what is not (simply, without qualification).
Note: Aristotle refers here to the material principle of the Academicians (= the Platonists). This doctrine about "the great and the small" or "indefinite dyad" was part the so called "unwritten teachings" of Plato as they were expounded in the lectures within the Academy.
Indeterminate Principle: The material principle or simply matter was conceived by Plato as a duplicity, a unity of opposing tendencies or extremes (more and less).
  At first glance Plato also posited three principles of reality ("the great", "the small" and the one = Form), but in fact he operated as if there are only two, the formal one and the indefinite (material) dyad. Aristotle repudiates inherent inconsistences of this view (two in itself and still two when a third factor is added).
Difference: Plato came close to recognize the indefinite dyad as a kind of subject, but was hampered to reach that conclusion by conceiving the material principle as one although it was in itself two. Furthemore, he treated "the great and the small" as the matter only, thus overlooking entirely the privation as an essential aspect of every change. Although Plato understood that some underlying nature is necessaruy to account for change he failed to realize that it must include both matter and privation. Practically he identified matter with privation. In contrast to the doctrines of Plato's Academy, Aristotle denies that matter is identical with privation and not-being. Matter is a not-being coincidentally (being not-this), whereas the privation is a not-being in its own right (non-existent, existent by not-being).
Mistakes: (1) The members of the Academy identified "the great and the small" (their material principle) with what is not (either "other than something" or "space" from the Timaeus). (2) Although the principle of "the great and the small" is in itself dual (a pair of opposites) they took it to be one, thus ignoring its real nature.
Enumeration of Principles:

- One principle is divine (good): form

- The second is the contrary: privation

- The third strives for the first: subject

Contrariety: The Academicians conceived contraries as striving to each other in a way that could only lead to their mutual destruction (female - male, beautiful - ugly). They did not realize that one contrary might be non-existent (as a privation, especially if it is regarded as something negative and "bad"). They wrongly refered the whole "evildoing" to the indeterminate nature of "the less and the more", that is to say to the entire material principle, while reserving the good aspect for the formal principle. (The view that "good" is determinate whereas "bad" is indeterminate was a Pythagorean doctrine.)
Matter: The nature that remains throughout change (material subject) is a kind of "mother" for what comes to be (the referrence is to Plato's description of chora in the Timaeus, 50d). But it is a joint cause (of two contrarites) along with the form. Due to the failure to distinguish between matter and privation the Platonists were forced to contend that one of the material contraries strives after its contrary. But this would lead to anihilation of the thing. So the question arises what pushes the change forward. If it cannot be the contrary then only form remains as a candidate. But the form does not strive for itself (because it does not lack itself). Thus Platonists were not able to explain how coming to be occurs.
Explanations: (1) What strives for the form is the matter. The female does not strive to be male, or the ugly to be beautiful, except coincidentally, with regard to the matter which could be ugly or female, but mater is not such in itself.
(2) The matter perishes and comes to be in a way, and in a way it does not. It perishes in the sense in which the privation is present in it (in fact privation perishes), but it does not perish or come to be as such (being what is potentially formed), but must persist as subject. Every coming to be presupposes a primary subject from which coming to be departs which is matter.
Impossibility: If we assume that matter comes to be it will have come to be from matter (the thing's primary subject), and so matter would be prior to matter. Similarly, if matter perishes it would finally come to matter, so it will have perished before it has perished.
Tasks: The study of the formal principle and of its status in general is reserved for the central books of the Metaphysics (bk. vii-ix). Natural and perishable forms are to be discussed in the second book of the Physics.



Book II (The Causes, Chance and Necessity)

Ch.1, Nature:

In the first book of the Physics Aristotle was using the expression "nature" mostly in the sense of an "underlying stuff" or subject. He has provisionally defined nature as the realm of constant though regulated change. Consequently, "natural things" were those that were subject to change in any of its types.
But this first determination of "nature" was very general and vague. We still do not quite understand what does it mean to exist "by nature" and to be "nature".
Note: It is obvious that the ancient usage of the word "nature" strongly deviates from ours. As indicated at the beiginning of this outline, "nature" for Aristotle is not a totality of living objects studied only by biology but something much more complex and comprehensive which includes the principles and the forms of coming to be. More specifically, in the second book of the Physics Aristotle is primarily concerned to explicate what does it mean for something to possess "a nature" (to be natural, to have an essence).


Aristotle now addresses this issue first by pointing out that existing "by nature" is a special case of being (existing) in general and then by explaining the "nature" of natural existence. What follows is something like the philosophy of life sciences or a study in the methodology of explanation in the sciences of nature.

General Supposition:

Everything that exists is a being.

Exhaustive Delineation:

"Among things that are (ta onta = beings), some exist by nature, some from other causes (aitia)."


Natural Things

Artificial Things

(1) "Natural things"

- those things that have a principle of motion and self-production in themselves.

Enumeration: animals and their parts, plants, simple bodies (air, fire, earth and water)
Note: It is somewhat surprising that animal parts (organs or waists?) as well as elements are included in this enumeration, although they lack either independent or structured existence. Parts of animals and portions of "elements" are not proper substances since they do not possess either functional unity or "nature" for that matter. The only reason for their inclusion may be that they are not products of any artifice either, but rather "potencies" that may appear separately in space. Automatic machines and gods are not an argument against Aristotle's dichotomy: the first belong to artifacts the latter to natural things.


(2) "Artificial things"

Things which are not constituted by nature - things that do not have a principle of change in themselves except coincidentally:


products of art, artifacts (coat, bed)

Common feature of both (1) and (2) is mobility. It includes the following four types of "movement":

Kinds of Change:

motion in space (local movement)
coming-to-be - passing away (becoming/decay)
increase - decrease (quantitative change)
alteration (qualitative change)

However, only things (1) have an innate impulse to move and change and they have it intrinsically (essentially), not coincidentally (accidentally). Sometimes things (2) can move and change not only under impact of external or natural causes but as it were "by themselves" (automates). However, they do not have an inner tendency to move/change and particularly not the power of self-production. Their movement is due either to a coincidence of artificial agency and patiency or to their natural material tendency (there are no absolute artifacts, produced without any natural material). A coincidental movement should not be confused with the movement originating from an intrinsic principle which is germain to natural things. Aristotle is therefore very careful in distinguishing coincidental movement both in natural and artificial object from the movement that is constitutive for the nature of natural objects alone.

  Coincidental Self-Originating:
(A) A self-healing Doctor "A man who is a doctor might himself be a cause of health to himself." Seemingly this proves that an artificial movement originates from itself (the doctor who is an artist or artisan heals himself in that capacity). However, these are two different movements: 1. The practicing of medicine as an art (techne), and 2. The regaining of health as natural process (physis). The doctor has the origin of both 1 and 2 in himself, but of 2 not as a doctor - only as a human patient. Conversely, the origin of medical knowledge is not in the human being qua human, and in that sense its possession is coincidental to being human or patient. On the other hand, that somebody is healing does not imply that he/she is a doctor as that somebody is a doctor does not mean that he/she is sick. This could happen, but in our culture the "two characteristics" are often (not sometimes as Aristotle says) separated due to both medical and legal reasons.
(B) A sprouting Bed An artifact can have a principle of change in itself insofar as it is made out of natural bodies. For instance: A bed could be viewed as a piece of wood and in that capacity it could change under influence of other elements or even originate a new sprout (if burried). But that happens coincidentally, because bed is not wood as such. It is wooden. (Only what is something else than wood, can be wooden - figures in chess, although we can say colloquially when playing: "move that piece of wood".) Thus everything a bed might originate as a piece of wood is accidental to its nature = being a bed. A bed has the origin of its being bed in somebody's intention and skill to make it out of wood. It can be only an accidental cause for itself, because it cannot produce itself or other beds. If it produces something at all that outcome cannot be in accord with what it is in itself.
Rule: Only natural things have the principle of their production in themselves. In artificial things the origin of movement is typically external, as is the case with a house. Even if the principle appears to be physically inside some of them, its status coincidental, not its own right.
Does Nature Exist?

We speak about natural things while assuming that they exist. Is it a justified assumption? Physical studies would be impossible if there were no subjects to study. Thus it makes sense to ask first whether nature exists at all. But the existence of natural objects is so obvious that any (syllogistic) proof (if possible at all) could only give a lesser amount of evidence for the existence of nature than what we obtain by simply looking around. In general, one needs to discriminate what is known "of itself" from what is derived and not to deduce the former from the latter. By the same token any proof regarding colors would be only about the names of colors without supplying any additional understanding of them. Unless we want to be like blinds discussing colors we can skip the question of existence and proceed directly to the question of essence:

What is Nature?

Initial Determination: "Nature is a principle or cause of motion and of stability in that to which it belongs primarily, in virtue of itself and not coincidentally."
Note: Nature is a cause  in the sense of origin, that belongs intrinsically and essentially to the "moving" beings. The stress is not that much on self-movement as on the identity of origin and essence.

Specific Determination:

Nature manifests itself in self-production. Natural things have the power of self-generation, specifically inasmuch as they are themselves.
Ontological Determination:
"Each of them (those things with a nature) is a substance, for it (substance) is a subject, and nature is always in a subject."

Having a nature is equal to being a substance (relatively independent, discernible and recognizable entity, bearer of identity, essential form underlying attributes).

Essence: As a realm of constant change nature would remain unintelligible and inexplicable if there were not some essential and permanent characteristics conveniently designated as substances.
Consequently, Aristotle understands nature as essential characteristic of something - not as a totality of living beings.
Nature is the substance or subject of a particular thing.
Subject - Attributes Distinction:
Natural substances are self-subsistent entities, whose nature underlies various affects  and persists throughout all changes. This is the most fundamental distinction between "something" and its attributes.
To exist by nature or to exist "according to nature" means to have a nature, to be a substance or to be an attribute
"The term 'according to nature' is applied both to these things (substances) and also to the attributes which belong to them in virtue of what they are (properties)."

What is the Nature and Substance of Natural Things?

Materialist Answer: The nature of a natural object is its "primary underlying matter". The substance is the material that persists continuously, while it is affected in various ways (affections, states, dispositions).

Philosophical Lexicon

Affection (Latin: affectum): That which belongs to something as its characteristic.
State: The mode of being of something.
Disposition (Latin: dispositio): The tendency to behave in a certain way.

Antiphon's Argument: (A) Nature as the proximate matter  
A buried wooden bed would not give birth to a bed, only to a wood - if it is germinated and puts forth a shoot. (fact)
The arrangement of wood into a bed in accordance with the rules of art proves to be merely an accidental attribute of the wood, which is the real nature and substance. (conclusion)
Radicalization of A: (B) Nature as the ultimate matter
"But if the material of each of these objects has itself the same relation to something else, say bronze (or gold) to water, bones (or wood) to earth and so on, that (they say) would be their nature and substance." (premise)
Thus "simple bodies" (= elements) are the nature and substance as eternal constituents of everything. (conclusion)
Objection to A and B:

What is the nature of matter? Since ultimate elements are not made out of anything else, we cannot determine their nature by reference to their constituents. In addition, by applying solely the "made of" criterion we do not pay justice to the fact that the nature of natural things is determined by their self-regulated motions.
Some motions of natural things are due to the matter they are made of, but many are manifestations of their substantial form.

Formalist Answer:

The nature is the shape (morphe) and the form (eidos), which is specified in the definition (logos).
Not everything has a nature or definition: amorphous things do not possess nature, although they possess matter. Therefore, the form and the shape bring about the nature of something. A combination with matter could be at best "by nature" or "according to nature".

(I) The concept and the name of something are based on the actual form. Comparison with artifices and their materials. What exits only potentially does not have its full nature and cannot be called or defined as the final product. Matter exists only potentially with regard to that what it is supposed to be at the end. To obtain its nature, it has to receive its form specified in the definition. Only then it becomes actually what it is by its name and concept. Form is the substance of naming and defining things as to what they are both in art and in nature.
Therefore, the form is the nature.

(II) The form determines natural reproduction. Analogy with art.  Man is born from (another) man, not from earth or from a bed. A bed cannot beget another bed. It can perhaps produce another wood. But wood is not a bed. What makes one bed a bed are its form and function. Antiphon is right in claiming that what reproduces itself is characteristic for substance, but his example points to the shape or naturalness of the form. Artistic production is determined by the form as well as natural generation. But man produces man as organized structure, not simply as flesh and bones. If capacity to reproduce itself makes a thing have a nature, then what gives regularity to that process is the form which regulates development.
Therefore, the form is the nature.

(III) The form determines the end of becoming. Contrast with art. Becoming (growing) is a road of a nature towards the nature. In difference to artifice (doctoring), which does not lead to itself but to something else (health), a natural thing stands both at theonset and at the end of reproduction. Moreover, the growing being is the same as the mature (grown) being, because what grows is basically what it is growing into - a form. (The form as an inner principle is the same in both the genitor and the offspring, although they are two different individuals of the same kind.)
Therefore, the form is the nature.

Philosophical Lexicon

Potentiality (Latin: potentia): something that exists as a possibility or tendency to become something.

Actuality (Latin: actualitas): real existence; the achievement of what a thing potentially is.

The Nature of Physical Science

Subject Matter Given previous twofold (materialist and formalist) answer to the question about the nature of natural objects, Aristotle now asks what should be taken for the subject matter of natural science, the form or the matter, and how it should be considered. A comparison with mathematical objects highlights the difference between a purely formal and a complex science of motion/matter:

"Odd and even, straight and curved, and likewise number, line and figure, do not involve motion; not so flesh, bone and man - these are defined like snub nose, not like curved."

It is not possible to predicate "snubness" about anything else but nose and it has always to be a characteristic of a nose, i.e. of something very material, whereas the adjective curved could be ascribed to immaterial lines as well. On the other hand, although it is not conceivable apart from a nose - the matter - "snubness" is not due simply to the matter, but also to a form, or better to say to the lack of it, as indicated by the concluding statement of B1 that the form is also privation. Its double bind (logical and material) explains why Aristotle so often uses this seemingly bizarre expression. The "snubness" thus appears to be a universal metaphor for the double-track enquiry of the physical science.

Approach: Consequently, Aristotle has to correct the impression from B1 that the form is the only nature and the only object of scientific study.

"Since two sorts of things are called nature, the form and the matter, we must investigate its objects as we would the essence of snubness, that is neither independently of matter nor in terms of matter only."

If there are two natures and two kinds of principles, natural philosophy must operate with two types of explanations. Complete and appropriate answers in the realm of physical sciences have to be formulated in the language of hylomorphism (meaning: describing natural things as unities of both the form and the matter). Truly, this methodological conclusion is given in a hypothetical mode ("if art imitates nature, and it is the part of the same discipline to know the form and the matter"), but that "if" is based on the previously well established (in Aristotle's eye) analogy between art and nature as well as on the synthesis of experience and science in art. Dual character of natural study is required by the subject itself and additionally manifested in our language. Knowledge of how black bile, yellow bile, phlegm and blood work is an indispensable part of medical science, although it is clearly about particular material substances. Only their balance, responsible for our healthy condition, can be perhaps considered as the form sought by the theoretical side of medical art (science of human nature).

Form-Matter: "Matter is a relative thing - for different forms there is different matter." Particularly in natural things it is difficult to separate form from the matter and the other way round. Unlike artifacts, natural things require very specific matter which forces Aristotle to rely on examples from art whenever he has to demonstrate the difference between the two.

What is composed of form and matter is not nature, but natural. Thus man is not nature, but natural. Since any individual being is made up of matter and form, it is a being by nature, not nature as either the form or the matter. The composition is not the nature in the sense of B1. Only form and matter could be the nature of something. Neither the simple characteristics or compounds are nature.

As a science physics, of course, has to focus on forms and ends of nature.

Teleological Answer:

The nature is an end that something is for.
"In a sense we are an end", because "we use everything as if it was for our sake."
This does not mean that the last stage in development is the end for the sake of which one being is born and lives. Aristotle would not accept the existentialist view that man is a being-toward-death:
"The poet was carried away into making an absurd statement when he said: /on the occasion of someone's death/ 'He has /reached/ the end for the sake of which he was born.'"
Aristotle makes a distinction between the factual terminus of life and the end in the sense of fulfillment of our potentials. In view of this distinction it is ridiculous to equate inevitable death with our human purpose. Although death comes of necessity to living beings, but is not for the sake of something. It is only something which follows from the perishable character of matter.
Although he extols man as the beneficiary of all other living beings Aristotle does not entrust humans with the mastership over the whole of nature in the sense of modern large scale manipulation and global dominance.

Hylomorphism: The theory that the universe is composed of matter and form in inseparable unity throughout.

Teleology: the study of final causes or of phenomena exhibiting purposes.

Existentialism: a view that existence precedes essence, that is, forms do not determine existence to be what it is.

Combination Dictum:

"Man is begotten by man and by the sun as well."  The nature of an organism as instantiated in one actual individual gives us an idea as what it is to be that organism. At the same time it is operative as a dynamic force pushing for its realization and reproduction. As such it determines the outcome of natural self-reproduction: man can only give birth to a man, not to a horse or to a dandelion. Man's offspring has the same form as its parents, the identity of species is being preserved despite all possible individual differences.
This does not mean that in the process of natural generation only internal (formal) factors are involved. Many external factors play a big role as well and that is indicated with the strange mention of the sun. The sun represents a whole range of accidental material factors that are responsible for individualization of particular organisms.

The Physics is not a theory of nature in its entirety, but a theory of natural beings as such. It extricates the essence of nature from the natural form itself. But natural form is not separable except theoretically (in statement). Therefore "the student of nature is concerned only with things whose forms are separable indeed, but do not exist apart from matter". It is a task for first philosophy to determine what is separable and what it is like.


Physics is second philosophy and as such should be distinguished from mathematics, which (as geometry) studies physical forms separated from matter ("not as the limits of a natural body").


To be able to give a rational account of constant change in the realm of natural beings and consequently to lay ground for physics as an explanatory potent science Aristotle introduces a scheme of causal relations.

Nature itself is a principle and a cause of change. But we speak about the cause with regard to four different points of reference each pointing to one aspect of the more general question "why something is".

To ask "why something is" means to identify main factors in the process of potentiality realization. Aristotle explicates this question in a fourfold way:

1. Out of what has a thing come? Answer obtained by identifying: The Material Cause:


The material cause points to "that from which, as a constituent, an object comes into being." (For instance, the bronze of a statue.)

2. What is it? Answer obtained by identifying: The Formal Cause:


The formal cause embodies the essential nature (all essential attributes) and represents the model or archetype of the outcome; conceptually it is expressed in the definition (logos). (It is the idea of the statue as present in artist's head.)

3. By means of what is it? Answer obtained by identifying: The Efficient Cause:

  The efficient cause is "the source of the change or rest"; it is the moving cause: "what makes of what is made and what changes of what is changed" (the sculptor who makes the statue).

4. For the sake of what is it? Answer obtained by identifying: The Final Cause:

  The final cause states "that for the sake of which" a thing is done, or, in other words, it explicates something's end (the final shape or the effect on the audience which admires the statue).

Note: Although Aristotle himself holds all these four causes responsible for any real change and movement (aitia in Greek are those things that are "guilty" or responsible for something), they are rather demarcation points of change as revealed in our language than true causes (with a possible exception of the efficient cause, which is nowadays considered to be the only real cause out of the four). In difference to the modern concept of causation, which always implies a sequence of two events, Aristotle envisions causation as a single event of double actualization: agent's potential to effectuate something and patient's potential to sustain that change.

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