Commentary Aristotle Physics
Lecture 5. Physics determines what and how many causes there are
Now that we have established these distinctions, we must proceed to consider causes, their character and number. Knowledge is the object of our inquiry, and men do not think they know a thing till they have grasped the why of it (which is to grasp its primary cause). So clearly we too must do this as regards both generation and passing away and every kind of physical change, in order that, knowing their principles, we may try to refer to these principles each of our problems.
In one sense, then, that from which something comes to be when it is in it is called “cause”—for instance, the bronze of the statue, the silver of the bowl, and the genera of these things.
In another sense, the form or the exemplar—the statement of the essence—and its genera are called “causes” (i.e., of the octave, the relation of 2:1, and generally number), and the parts in the definition.
Again, that from which there is a beginning of motion or rest is a cause, such as the man who gave advice, the father as cause of the child, and generally what makes of what is made and what causes change of what is changed.
Again, the end or “that for the sake of which” a thing is done is a cause: health is the cause of walking about.
(“Why does he walk?” we say, “That he may become healthy,” and, having said that, we think we have assigned the cause.)
The same is true also of all the intermediate steps that are brought about through the action of something else as means toward the end, such as reduction of flesh, purging, drugs, or surgical instruments as means toward health.
All these things are for the sake of the end, though they differ from one another in that some are activities and others are instruments. This perhaps exhausts the number of ways in which the term “cause” is used.
As the word has several senses, it follows that there are several causes of the same thing (not merely accidentally):
for instance, both the art of the sculptor and the bronze are causes of the statue. These are causes of the statue qua statue, not in virtue of anything else that it may be—only not in the same way, the one being the material cause, the other the cause from which the motion comes.
Some things cause each other reciprocally, as hard work causes fitness and vice versa, but not in the same way: the one is the end, and the other is the origin of change.
Further, the same thing is the cause of contrary results. For that which brings about one result by its presence is sometimes blamed for bringing about the contrary by its absence. Thus, we ascribe the wreck of a ship to the absence of the pilot, whose presence was the cause of its safety.
All the causes now mentioned fall into four obvious divisions. The elements are the causes of syllables, earth of vases, fire and the like of bodies, the parts of the whole, and the premises of the conclusion, all in the sense of “that from which.”
Of these pairs, the one set are causes in the sense of substratum, such as the parts, and the other set in the sense of essence—the whole and the combination and the form.
But the seed and the doctor and the adviser, and generally the maker, are all sources from which the change or stationariness originates, while the others are causes in the sense of the end or the good of the rest, for “that for the sake of which” means what is best and the end of the things that lead up to it.
(Whether we say “the good itself” or the “apparent good” makes no difference.) Such, then, is the number and nature of the kinds of cause.
176. Having shown what natural science considers, the Philosopher here begins to designate the causes from which it should demonstrate.
This section is divided into two parts.
First, he treats the causes;
second, at “now the causes” (198a22; [241]), he points out the causes from which natural science should demonstrate.
Concerning the first part, he makes two points.
First, he shows the need for treating the causes;
second, at “in one sense” (194b23; [177]), he begins to treat the causes.
He says first (194b16) that, after it has been determined what falls under the consideration of natural science, there remains to be considered the causes—what they are and how many there are. This is so because the business of studying nature is not ordered to operation, but to science. For we are not able to make natural things, but only to have science of them. Now, we do not think that we know anything unless we grasp the why, which is to grasp the cause. Hence it is clear that we must observe generation, corruption, and every natural change in such a way that we know the causes and reduce each one about which we seek the why to its proximate cause.
He says this because the consideration of causes insofar as they are causes is proper to first philosophy. For insofar as it is a cause, a cause does not depend upon matter for its existence, because the account of cause is found also in those things that are separated from matter. But the consideration of causes is taken up by the natural philosopher because of a certain necessity. However, he considers causes only insofar as they are the causes of natural changes.
177. Next, at “in one sense” (194b23), he treats the causes.
Concerning this, he makes three points.
First, he names the clearly diverse species of causes;
second, at “but chance also” (195b31; [198]), he treats certain less obvious causes;
third, at “it is clear, then” (198a14; [239]), he shows that the causes are neither more nor less.
The first part is divided into two parts.
First, he treats the species of causes;
second, at “now the modes” (195a27; [187]), he treats the modes of diverse causes in each species.
Concerning the first part, he makes two points.
First, he sets forth the different species of causes;
second, at “all the causes” (195a15; [183]), he reduces them to four.
Concerning the first part, he makes two points.
First, he sets forth the different causes;
second, at “as the word” (195a4; [182]), he points out certain consequences that follow from the above-mentioned diversity.
178. He says first (194b23) that, in one way, a cause is said to be that from which something comes to be when it is in it, as bronze is said to be the cause of a statue and silver the cause of a vase. The genera of these things, such as the metallic or the liquifiable and such things, are also called causes of these same things.
He adds when it is in it in order to differentiate this cause from the privation and the contrary. For the statue indeed comes to be from bronze, which is in the statue when it is made. But it also comes to be from the unshaped, which is not in the statue when it is made. Hence, bronze is a cause of statue but the unshaped is not, since it is only a per accidens principle, as was said in book 1.
179. Second, a cause is said to be the species and exemplar (194b26). This is called a cause insofar as it is the quidditative account of the thing, for this is that through which we know of each thing what it is. And, as was said above, just as even the genera of matter are called causes, so also the genera of a species are called causes.
His example is that harmony of music called the octave. The form of an octave is a proportion of the double, which is a relation of two to one. For musical harmonies are constituted by the application of numerical proportions to sounds as to matter. And, since two or the double is the form of that harmony that is the octave, the genus of two, which is number, is also a cause. Thus, just as we say that the form of the octave is that proportion of two to one (which is the proportion of the double), so also we can say that the form of the octave is that proportion of two to one, which is multiplicity.
And so, all of the parts that are placed in the definition are reduced to this mode of cause. For the parts of the species are placed in the definition, but not the parts of the matter, as is said in Metaphysics 7.10.
Nor is this contrary to what was said above about matter being placed in the definitions of natural things. For individual matter is not placed in the definition of the species, but common matter is. Thus, flesh and bones are placed in the definition of man, but not this flesh and these bones. The nature of the species, therefore, which is constituted of form and common matter, is related as a formal cause to the individual that participates in such a nature, and to this extent, it is said that the parts that are placed in the definition pertain to the formal cause.
It should also be noted that he posits two things that pertain to the quiddity of the thing: the species and the exemplar. For there is a diversity of opinions concerning the essences of things. Plato held that the natures of species are certain abstract forms, which he called exemplars and ideas, and because of this, he posited the exemplar or paradigm. However, those natural philosophers who said something about form placed the forms in matter, and because of this, he named them species.
180. Next, he says that that from which there is a beginning of motion or rest is in some way called a cause. Thus, one who gives advice is a cause, and the father is a cause of the son, and everything that brings about a change is a cause of that which is changed.
It must be noted with reference to causes of this sort that there are four kinds of efficient cause: the perfecting, the preparing, the assisting, and the advising causes.
The perfecting cause is that which gives fulfilment to motion or change, as that which introduces the substantial form in generation.
The preparing or disposing cause is that which renders matter or the subject suitable for its ultimate completion.
The assisting cause is that which does not operate for its own proper end, but for the end of another.
The advising cause, which operates in those things that act because of something proposed to them, is that which gives to the agent the form through which it acts.
For the agent acts because of something proposed to him through his knowledge, which the advisor has given to him, just as in natural things, the generator is said to move the heavy or the light insofar as it gives the form through which they are moved.
181. Further, he posits a fourth mode of cause. A thing is called a cause as an end. This is that for the sake of which something comes to be, as health is said to be a cause of walking. And this is evident because it answers the proposed question of why. For when we ask, “Why does he walk?” we say, “That he may become healthy”; and we say this thinking that we assign a cause. And thus he gives more proof that the end is a cause than that the other things are causes, because the end is less evident, inasmuch as it is last in generation.
And he adds further that all things that are intermediates between the first mover and the ultimate end are in some way ends. Thus, the doctor makes the body thinner in order to produce health, and so health is the end of thinness. But thinness is produced by purgation, and purgation is produced by a drug, and the drug is prepared by instruments. Hence, all of these things are in some way ends, for the thinness is the end of the purging, the purging is the end of the drug, the drug is the end of the instruments, and the instruments are the ends in the operation or in the seeking for the instruments. And thus it is clear that these intermediate things differ from each other, insofar as some of them are instruments and some of them are operations performed by instruments.
And he brings this out lest anyone think that only that which is last is a cause in the sense of that for the sake of which. For the name “end” seems to refer to something that is last. Thus, every end is last not simply, but in respect to something.
He finally concludes that this is perhaps all the ways in which the name “cause” is used. He adds perhaps because of the causes that are per accidens, such as chance and fortune.
182. Next, at “as the word has” (195a4), he makes clear three things that follow from what he has said about the different causes. The first point is that, since there are many causes, one and the same thing has many causes per se, and not per accidens. Thus, the art of the sculptor is a cause of a statue as an efficient cause but bronze is a cause as matter. And so it is that many definitions of one thing are sometimes given in accordance with the different causes. But the perfect definition embraces all of the causes.
The second point is that some things are causes of each other in respect to different species of cause. Thus, work is an efficient cause of a good habit, yet a good habit is a final cause of work. For nothing prevents a thing from being both prior and posterior to another according to different accounts. The end is prior according to account, but posterior in existence; the converse is true of the agent. And in like manner, the form is prior to matter with respect to the account of being a complement, but the matter is prior to form with respect to generation and time in everything that is moved from potency to act.
The third point is that the same thing is, at times, the cause of contraries. Thus, through his presence, the navigator is the cause of the safety of the ship; through his absence, however, he is a cause of its sinking.
183. Next, at “all the causes” (195a15), he reduces all the causes mentioned above to four species. He says that all the causes enumerated above are reduced to four modes that are evident. For elements such as letters are causes of syllables, and in like manner earth is a cause of vases, and silver of a vial, and fire and such things (the simple bodies) are causes of bodies. And, in the same way, every part is a cause of the whole, and the premises—that is, the propositions in a syllogism—are a cause of the conclusion. And all these are understood as causes in the same way, namely, as a cause is that from which something comes to be: for this is common to everything mentioned. However, of all the things just enumerated, some are causes as matter and some as form, which causes the quiddity of the thing. Thus, all parts, such as the elements of syllables and the four elements of mixed bodies, are causes as matter. But those things that imply a whole or a composition or some species are understood as form. Thus species is referred to the forms of simple things, and the whole and composition are referred to the forms of composites.
184. But there seem to be two difficulties here.
The first is that he says the parts are material causes of the whole, when above he reduced the parts of the definition to the formal cause. It can be said that he spoke above of the parts of the species that fall in the definition of the whole, but here he speaks of the parts of the matter in whose definition falls the whole. Thus, circle falls in the definition of semicircle. But it would be better to say that, although the parts of the species that are placed in the definition are related to the suppositum of nature as a formal cause, they are nevertheless related to the very nature of which they are parts as matter. For all parts are related to the whole as the imperfect to the perfect, which is, indeed, the relation of matter to form.
Further, a difficulty can be raised with reference to what he says about propositions being the matter of conclusions. For matter is in that of which it is the matter. Hence, speaking of the material cause above, he said that it is that from which something comes to be when it is in it. But propositions are apart from the conclusion. But it must be pointed out that the conclusion is formed from the terms of the propositions.
Hence, in view of this, the propositions are said to be the matter of the conclusion insofar as the terms that are the matter of the propositions are also the matter of the conclusion, although they are not in the same order as they are in the propositions. In this same way, flour is called the matter of bread, but not insofar as it stands under the form of flour.
And so propositions are better called the matter of the conclusion than conversely. For the terms that are joined in the conclusion are posited separately in the premises. Thus we have two modes of cause.
185. Some things are called causes for another reason: because they are a principle of motion and rest. And, in this way, the seed that is active in generation is called a cause. Likewise, the doctor is called a cause of health according to this mode, and so also the adviser is a cause according to this mode, and everyone who makes something.
Another text reads, and propositions. For although propositions, insofar as their terms are concerned, are the matter of the conclusion, as was said above, nevertheless insofar as their inferential power is concerned, they are reduced to this genus of cause. For the principle of the discourse of reason to its conclusion is from propositions.
186. Another meaning of “cause” is found in other causes, namely, insofar as the end or the good has the account of a cause. And this species of cause is the most powerful of all the causes, for the final cause is the cause of the other causes. It is clear that the agent acts for the sake of the end.
And likewise it was shown above in regard to artificial things that the form is ordered to use as to an end, and matter is ordered to form as to an end. And, to this extent, the end is called the cause of causes. Now, since he has said that this species of cause has the account of a good, while it sometimes happens in those things that act by choice that the end is evil, he forestalls this difficulty by saying that it makes no difference whether the final cause is a true or an apparent good, because what seems to be good can only move under the account of being good.
And thus he finally concludes that the species of cause are as many as were mentioned.