by
Aristotle

Plato (left) and Aristotle in Raphael’s 1509 fresco, The School of Athens

Book I

Chapter I

All men by nature are actuated with the desire of knowledge, and an indication of this is the love of the senses; for even, irrespective of their utility, are they loved for their own sakes; and pre-eminently above the rest, the sense of sight. For not only for practical purposes, but also when not intent on doing anything, we choose the power of vision in preference, so to say, to all the rest of the senses. And a cause of this is the following, — that this one of the senses particularly enables us to apprehend? whatever knowledge it is the inlet of, and that it makes many distinctive? qualities manifest.

By nature then, indeed, are animals formed endowed with sense; but in some of them memory is not innate from sense, and in others it is. And for this reason are these possessed of more foresight, as well as a greater aptitude for discipline, than those which are wanting in this faculty of memory. Those furnished with foresight, indeed, are yet without the capability of receiving instruction, whatever amongst them are unable to understand the sounds they hear; as, for instance, bees, and other similar tribes of animals; but those are capable of receiving instruction as many as, in addition to memory, are provided with this sense also.

The rest, indeed, subsist then through impressions and the operations of memory, but share experience in a slight degree; whereas the human race exists by means of art also and the powers of reasoning.

Now, experience accrues to men from memory for repeated acts of memory about the same thing done constitute the force of a single experience: and experience seems to be a thing almost similar to science and art.

But science and art result unto men by means of experience for experience, indeed, as Polus saith, and correctly so,’ has produced art, but inexperience, chance. But an art comes into being when, out of many conceptions of experience, one universal opinion is evolved with respect to similar cases. For, indeed, to entertain the opinion that this particular remedy has been of service to Callias, while labouring under this particular disease, as well as to Socrates, and so individually to many, this is an inference of experience; but that it has been conducive to the health of all, — such as have been defined according to one species, — while labouring under this disease, as, for instance, to the phlegmatic, or the choleric, or those sick of a burning fever, this belongs to the province of art.

As regards, indeed, practical purposes, therefore, experience seems in no wise to differ from art; nay, even we see the experienced compassing their objects more effectually than those who possess a theory without the experience. But a cause of this is the following — that experience, indeed, is a knowledge of singulars, whereas art, of universals; but all things in the doing, and all generations, are concerned about the singular: for he whose profession it is to practise medicine, does not restore man to health save by accident, but Callias, or Socrates, or any of the rest so designated, to whom it happens to be a man. If, therefore, any one without the experience is furnished with the principle, and is acquainted with the universal, but is ignorant of the singular that is involved therein, he will frequently fall into error in the case of his medical treatment; for that which is capable of cure is rather the singular.

But, nevertheless, we are of opinion that, at least, knowledge and understanding appertain to art rather than experience; and we reckon artists more wise than the experienced, inasmuch as wisdom is the concomitant of all philosophers rather in proportion to their knowledge.

But this is so because some, indeed, are aware of the cause, and some are not. For the experienced, indeed, know that a thing is so, but they do not know wherefore it is so; but others — I mean the scientific — are acquainted with the wherefore and the cause. Therefore, also, we reckon the chief artificers in each ease to be entitled to more dignity, and to the reputation of superior knowledge, and to be more wise than the handicraftsmen, because the former are acquainted with the causes of the things that are being constructed; whereas the latter produce things, as certain inanimate things do, indeed; yet these perform their functions unconsciously, — as the fire when it burns. Things indeed, therefore, that are inanimate, by a certain constitution of nature, perform each of these their functions, but the handicraftsmen through habit; inasmuch as it is not according as men are practical that they are more wise, but according as they possess the reason of a thing, and understand causes.

And, upon the whole, a proof of a person’s having knowledge is even the ability to teach; and for this reason we consider art, rather than experience, to be a science; for artists can, whereas the handicraftsmen cannot, convey instruction.

And further, we regard none of the senses to be wisdom, although, at least, these are the most decisive sources of knowledge about singulars; but they make no affirmation of the wherefore in regard of anything, — as, for example, why fire is hot, but only the fact that it is hot.

Therefore, indeed, is it natural for the person who first discovers any art whatsoever, beyond the ordinary power of the senses, to be the object of human admiration, not only on account of something of the things that have been discovered being useful, but as one that is wise and superior to the rest of men. But when more arts are being discovered — both some, indeed, in relation to things that are necessary, and others for pastime — we invariably regard such more wise than those,’ on account of their sciences not being for bare utility. Whence all things of such a sort having been already, procured, those sciences have been invented which were pursued neither for purposes of pleasure nor necessity, and first in those places where the inhabitants enjoyed leisure: wherefore, in the neighbourhood of Egypt the mathematical arts were first established; for there leisure was spared unto the sacerdotal caste. It has then, indeed, been declared in the Ethics what is the difference between an art and a science, and the rest of the things of the same description.

But, at present, the reason of our producing this treatise is the fact, that all consider what is termed wisdom to be conversant about first causes and principles; so that — as has been said on a former occasion — the experienced seem to be more wise than those possessing any sense whatsoever, and the artificer than the experienced, and the master-artist than the handicraftsman, and the speculative rather than those that are productive. That, indeed, wisdom, therefore, is a science conversant about certain causes and first principles is obvious.

Chapter II

Now, since we are engaged in investigating this science, the following must form a subject for our consideration; namely, about what kind of causes, and what kind of first principles, is this science — I mean wisdom — conversant. If, doubtless, one would receive the opinions which we entertain concerning the wise man, perhaps from this our proposed inquiry would be evident the more.

Now, in the first place, indeed, we go on the supposition that the wise man, especially, is acquainted with all things scientifically, as far as this is possible, not, however, having a scientific knowledge of them singly. In the next place, a person who is capable of knowing things that are difficult, and not easy for a man to understand, such a one we deem wise (for perception by the senses is common to all, wherefore it is a thing that is easy, and by no means wise). Further, one who is more accurate, and more competent to give instruction in the causes of things, we regard more wise about every science. And of the sciences, also, that which is desirable for its own account, and for the sake of knowledge, we consider to be wisdom in preference to that which is eligible on account of its probable results, and that which is more qualified for preeminence we regard as wisdom, rather than that which is subordinate, — for that the wise man ought not to be dictated to, but should dictate unto others; and that this person ought not to be swayed in his opinions by another, but one less wise by this man. Respecting this wisdom and wise men do we entertain such and so many suppositions.

But of these characteristics the scientific knowledge of all things must needs be found in him most especially who possesses the universal science for this person, in a manner, knows all things that are subjects of it. But, also, the most difficult nearly for men to know are the things that are especially universal, for they are most remote from the senses. But the most accurate of the sciences are those respecting things that are primary, in the most eminent sense of the word; for those from fewer principles are more accu- rate than those said to be from addition, as arithmetic than geometry. But, also, that science, without doubt, is more adapted towards giving instruction, at least, which speculates about causes; for those do afford instruction who assign the causes in regard of each individual thing. Now, understanding and scientific knowledge, for their own sakes, most especially reside in the science of that which is most particularly fitted for being scientifically known. For he who selects scientific knowledge, for its own sake, will especially choose that which is preeminently science; but such is that which is the science of that which is particularly fitting as an object of scientific knowledge, and particularly fitting as objects of scientific knowledge are first principles and causes; for on account of these, and by means of these, are the other objects of knowledge capable of being made known: but not these by means of those things that are subordinate to them. Most fit for preeminence likewise amongst the sciences, and fit for preeminence in preference to that which is subservient, is the science which communicates the knowledge of that on account of which each thing is to be done; but this constitutes the good in each particular, but, in general, that which is the best in every nature.

From all, therefore, that has been stated, the sought-for appellation lights upon the same science; for it is necessary that this be a science speculative of first principles and of causes, for the good, also, viewed as a final cause, is one from amongst our classified list of causes.

But that the science under investigation is not a science employed in producing,’ is evident from the case of those who formed stems of philosophy in the earliest ages. For from wonder men, both now and at the first, began to philosophize, having felt astonishment originally at the things which were more obvious, indeed, amongst those that were doubtful; then, by degrees, in this way having advanced onwards and, in process of time, having started difficulties about more important subjects, — as, for example, respecting the passive conditions of the moon, and those brought to pass about the sun and stars, and respecting the generation of the universe. But he that labours under perplexity and wonder thinks that he is involved in ignorance. Therefore, also, the philosopher — that is, the lover of wisdom — is somehow a lover of fables, for the fable is made up of the things that are marvellous. Wherefore, it for the avoidance of ignorance; men from time to time have been induced to form systems of philosophy, it is manifest that they went in pursuit of scientific knowledge for the sake of understanding it, and not on account of any utility that it might possess. But the event itself also bears witness to the truth of this statement; for on the supposition of almost all those things being in existence that are requisite towards both ease and the management of life, prudence of such a sort as this began to be in requisition. Therefore is it evident that we seek scientific knowledge from no other actual ground of utility save what springs from itself.

But as we say a free man exists who is such for his own sake, and not for the sake of another, so, also, this alone of the sciences is free, for this alone subsists for its own sake.

Wherefore, also, the acquisition of this science in may be justly regarded as not human, for, in many instances, human nature is servile.’ So that, according to Simonides, the Deity only should enjoy this prerogative; yet that it is unworthy for a man not to investigate the knowledge that is in conformity with his own condition. But if, in reality, the poets make any such assertion, and if the Godhead is in its nature constituted so as to envy, in this respect it is especially natural that it should happen, and that all those that are over-subtle should be unfortunate: but neither does the Divine essence admit of being affected by envy, but — according to the proverb — the bards utter many falsehoods. Nor ought we to consider any other science more entitled to honour than such as that under investigation at present. For that which is most divine is also most worthy of honour. But such will be so in only two ways; for that which the Deity would especially possess is a divine one amongst the sciences; and if there is any such science, this would be the case with the science of things divine. But this science, such as we have described it, alone is possessed of both of these characteristics; for to all speculators doth the Deity appear as a cause, and a certain first principle and such a science as this, either God alone, or he principally, would possess. Therefore, indeed, may all sciences else be more requisite than this one; but none is more excellent.

It is, indeed, necessary, in a manner, to establish the order of this science, in its development, in a direction contrary to the speculations hat have been carried on from the beginning. For, indeed — as we have remarked — all men commence their inquiries from wonder whether a thing be so, — as in the case of the spontaneous movements of jugglers’ figures to those who have not as yet speculated into their cause; or respecting the solstices, or the incommensurability of the diameter; for it seems to be a thing astonishing to all, if any quantity of those that are the smallest is not capable of being measured. But it is necessary to draw our inquiry to a close in a direction the contrary to this, and towards what is better, according to the proverb. As also happens in the case of these, when they succeed in learning those points; for nothing ‘would a geometrician so wonder at, as if the diameter of a square should be commensurable with its side. What, therefore, is the nature of the science under investigation has been declared; as, also, what the aim should be which the present inquiry and the entire treatise should strive and attain.

Chapter III

BUT since it is manifest that one ought to be in possession of a science of primary causes (for then we say that we know each individual thing when we think that we are acquainted with the first cause); and since causes are denominated under four different heads, the first of which we assert to be the substance and the essence of a thing (for the inquiry of the wherefore, in the first instance of a thing, is referred to the last reason, but the first wherefore of a thing is a cause and first principle); and the second cause we affirm to be the matter and the subject; and the third is the source of the first principle of motion; and the fourth, the cause that is in opposition to this, — namely, both the final cause and the good; for such is an end of every generation;

Therefore, although there has been a sufficient amount of speculation concerning these in our treatise on Physics let us, however, bring forward those who before our time have approached to an examination of entities, and have formed systems of philosophy respecting truth. For it is obvious that they also affirm that there are in existence certain first principles and causes; therefore will it, at any rate, be of service to our present treatise should we take a review of these philosophers; for either we shall thereby discover a certain different description of cause, or we shall, in preference, repose our confidence in those that have been already enumerated.

Now, the majority of those who first formed systems of philosophy consider those that subsist in a form of matter to be alone! the principles of all things; for wherefrom all entities arise, and wherefrom they are generated, as from an original, and whereto they are corrupted, — ultimately the substance, indeed, remaining permanent, but in its passive states undergoing a change, — this they assert to be an element, and this a first principle of all things.

And for this reason they are of opinion that nothing is either produced or destroyed, in as much as such a constitution of nature is always in a state of conservation; as we say, that Socrates neither is absolutely brought into being when he may become handsome or musical, nor that he is destroyed when he may throw aside these habits on account of the fact of the subject, — namely, Socrates himself remaining permanent; so neither is it the case with anything else that it is either generated or corrupted anew. For it is necessary that there should be a certain Nature — either one or more than one — from which the other entities are produced, that remaining in a state of conservation. The plurality, indeed, and the species of such a first principle, all do not affirm to be the same.

But Thales, indeed, — the founder of this kind of philosophy, — affirms the nature just mentioned to be water, (wherefore, also, he declared the earth to be superimposed upon water) probably deriving his opinion from observing that the nutriment of all things is moist, and that even actual heat is therefrom generated, and that animal life is sustained by this (but that wherefrom a thing is produced, this is a first principle of all things); and doubtless for this reason, likewise, holding such a theory, both from the fact of the seeds of all things possessing a moist nature, and of water being a first principle of their nature to things that are humid.

But there are some who suppose those who lived in the most ancient times, and far previous to the present generation, and who first formed schemes of theology, to have also entertained opinions after this manner concerning Nature; for these philosophers constituted both Oceanus and Tethys as the parents of generation, and water as the object of adjuration amongst the gods, — called Styx by the poets themselves; for most entitled to respect is that which is most ancient, — now an object of adjuration is a thing most entitled to respect. Whether, therefore, there is this certain early and ancient opinion concerning Nature, in all likelihood would be an obscure point to decide. Thales, indeed, is said to have declared his sentiments in this manner concerning the first cause; for no one would deign to place Hippo along with these, on account of the meanness of his intellect.

But Anaximenes and Diogenes placed air before water, and especially as a cause of simple bodies; whereas, Hippasus of Metapontum, and Heraclitus of Ephesus, fire; but Empedocles introduced four bodies, — that is, one in addition to those three already mentioned, — adding earth as a fourth; for that these ever continued permanent; and further, that they are not produced, save that, either in plurality or in paucity, they are compounded together, or dissolved into one and from one component element.

But Anaxagoras of Clazomente — in age, indeed, being prior to this speculator, but in his works subsequent to him — maintains that first principles are infinite. For he asserts that almost all things being homogeneous — as water or fire — in this way are produced and destroyed by concretion and dissolution merely; but that, in other respects, no entities were either brought into existence, or caused to cease to exist, but continued as things that are everlasting.

From these things, indeed, therefore, one would suppose that the only cause with these philosophers was that said to exist in a form of matter. But as these speculators advanced in this way, the thing itself guided them, and constrained them to investigate further for though every possible corruption and generation is from something subsisting, as one or more, yet why does this happen, and what is the cause of this, — for undoubtedly the subject, at least, itself is in no wise instrumental in making itself undergo a change Now, I say, for example, that neither the wood nor the brass is the cause of either of these bodies undergoing a change; neither does the wood, indeed, produce a bed, and the brass a statue; but there is something else that is a cause of change. But the investigation of this is the investigation of a different principle, that is, the second cause, — as we have stated, — the principle of the origin of motion.

Those, indeed, therefore, who from the earliest times have altogether adopted such a method as this, and affirm the subject to be one, have created no difficulty for themselves; but some of these, at least, who say that it is one, as if overpowered by this investigation, assert that the one is immoveable, and the entire of nature, not only according to generation and corruption, — for this is an ancient dogma, and one which all acknowledge, — but also according to every other change, whatever; and this a tenet peculiar to themselves. Of those, indeed, therefore, who affirm the universe to be one merely, to none has it occurred to see clearly into a cause of such a kind, unless, perhaps, to Parmenides, and to him so far as that he lays down not one merely, but, somehow, even two causes to exist. And for those, truly, who make them more numerous is it allowable rather to assert the existence of such a cause as the efficient cause, — I mean those who make causes to be the hot and the cold or fire and earth; for they employ the fire as possessing a motive nature, but water and earth, and such like, as something that is contrary to this.

But after these philosophers, and after the assertion of principles of this sort, — as if on the grounds of their insufficiency to generate the nature of entities, — again constrained by actual truth, as we have said, they investigated the principle next following, in the way of a consequence. For of the excellent and beautiful order of some things, and of the production of others of the entities, it is not natural to assign, perhaps, either earth or anything of this kind as a cause; nor is it natural that they should think that it is; nor was it seemly, on the other hand, attribute so important a part to chance and fortune.

Now, whosoever affirmed mind, as in animals so also in nature, to be the cause of the system of the world, and of the entire harmony of it, the same appeared, as it were, of sober temperament, in comparison with the vain theorists of the earlier ages. Indeed, then, we know that Anaxagoras openly adopted these principles. Hermotimus of Clazomenea, however, has the credit assigned him of having put forward a similar theory of causation at an earlier period.

Those, indeed, therefore, who have entertained these opinions have laid down as a first principle of entities, at the same time the cause of their orderly arrangement, with such a one as that of the origin of motion in things.

Chapter IV

SOME one, however, might indulge in the surmise that Hesiod was the first to broach such description of cause as the above; and that this is the case with whatsoever other speculator, if any, that may have placed love or desire as a first principle in entities; as, for instance, also Parmenides: for this philosopher, likewise, in drawing up his scheme of the generation of the universe, says, — “The first thing of all the gods, indeed, plann’d he Love.”
But Hesiod’s words are, —
“First, indeed, of all was Chaos; but next in order,
Earth with her spacious bosom. Then
Love, who is pre-eminent amongst all the Immortals;”
just as if it were necessary that in entities there should subsist some cause which will impart motion, and hold bodies in union together. How, indeed, then, in regard of these, one ought to distribute them, as to their order of priority, can be decided afterwards.

But, also, since things contrary to those that are good appeared inherent in Nature, and not only order and the beautiful, but also disorder and what is base; and since the evil things were more numerous than the good, and the worthless than the fair, accordingly, some one else introduced harmony and discord, as a cause severally of each of these. For if any one would follow the subject up, and form his opinion according to the faculty of thought, and not according to the obscure assertions of Empedocles, he will find harmony, indeed, to be a cause of the things that are good, and discord of those that are evil. Wherefore, if any should say that Empedocles both, in a certain sense, affirms, and that he was the first to affirm, that the evil and the good are first principles, perhaps he would make such an assertion correctly, if the cause of all things that are good be the good itself, and of those that are evil the evil.

These persons, indeed, therefore, as we have said, even thus far have adopted into their Systems two causes, as we have defined them in our Physics, — I mean the material cause, and the principle of the origin of motion; that is, the efficient cause: obscurely, no doubt, and by no means clearly, but, in a manner, like the conduct of those who are unexercised in battles; for these latter, also, advancing forwards against their adversaries, strike frequently skillful blows: but neither do those combatants act thus from a scientific system, nor do these early speculators appear like men who understand that they are making the assertions which they actually are; for in no respect, almost, do they appear to employ these first principles, save to a small extent.

For Anaxagoras, also, employs mind as a machine’ for the production of the orderly system of the world; and when he finds himself in perplexity as to the cause of its being necessarily so, he then drags it in by force to his assistance; but, in the other instances, he assigns, as a cause of the things that are being produced, everything else in preference to mind.

And Empedocles, to an extent further than this last-named philosopher, employs his causes, however, neither adequately, nor does he discover in them that which confessedly is involved in them. Frequently, at least, in his system the harmony indeed separates, and the discord unites things together. For when the universe may be dissolved into its component elements, by reason of discord, then fire is commingled into one and each of the rest of the elements; but when all things, by reason of harmony, may unite into one, it is necessary that the parts from each undergo separation again. Empedocles then, indeed, — in contradistinction to the early speculators, — first introduced this cause, having divided it, not having constituted, as single, the first principle of motion, but first principles thereof which are different and opposite. But, moreover, the reputed elements, in form of matter, he was the first to assert the existence of as being four in number; he did not, doubtless, employ at least four, but regarded them as if there were only two; fire by itself; and those things that are opposed to this, as one nature, — namely, both earth, and air, and water. But one may acquire this information by drawing the speculation itself from his poetry. This philosopher, indeed, therefore, as we have stated, enumerated his first principles in this way, and affirmed them to be so many in number.

But Leucippus, and his companion Democritus, assert that the full and the empty are elements; terming, for instance, the one, indeed, an entity, and the other a nonentity; and of these, the full and solid they call an entity, and the empty and the attenuated, a nonentity. Wherefore, they say that entity, in no respect less than nonentity, has, an existence, because neither has the vacuum a being more than corporeity, and that these are the causes of entities as material causes.

And as they who make the substance, which is the subject, one, generate all things else by means of the passive conditions of this substance, assigning the rare and the dense as first principles these affections, in the same manner these also affirm that differences are causes of the other things. They, indeed, say that these are three, even figure, and order, and position; for they affirm that entity differs merely in rhythm, and diathege, and trope;’ out of these the rhythm is figure, and the diathege order, and the trope position. For, indeed, the letter A differs from the letter N in figure, and AN from NA in order, and Z from N in position. But respecting motion, whence or how it exists in entities, in like manner, with the rest of the early speculators, have these carelessly neglected such inquiries. Respecting, then, two causes of the four, according to the statements we have just made, so fax has it appeared that an inquiry has been prosecuted by our predecessors.

Chapter V

BUT amongst these, and prior to them, those called Pythagoreans, applying themselves to the study of the mathematical sciences, first advanced these views; and having been nurtured therein, they considered the first principles of these to be the first principles of all entities. But since, among these, numbers by nature are the first, and in numbers they fancied they beheld many resemblances for entities and things that are being produced, rather than in fire, and earth, and water; because, to give an instance, such a particular property of numbers is justice, and such soul and mind; and another different one is opportunity; and it is the case, so to speak, in like manner with each of the other things; Moreover, also, in numbers discerning the passive conditions and reasons of harmonies, since it was apparent that, indeed, other things in their nature were in all points assimilated unto numbers, and that the numbers were the first of the entire of Nature, hence they supposed the elements of numbers to be the elements of all entities, and the whole heaven to be an harmony and number. And as many phenomena as they could demonstrate to be conformable, both in their numbers and harmonies, with the passive conditions and parts of the heaven, and with its entire arrangement, these they collected and adapted to their philosophy: and if there was any interval left anywhere, they supplied the deficiency, in order that there might he a chain of connexion running through their entire system? Now, I say, as an illustration, since the decade seems to be a thing that is perfect, and to have comprised the entire nature of numbers, hence they also assert that the bodies that are borne through the heaven are truly ten in number; and whereas nine only are apparent, on this account they constitute the confronting earth tenth. But respecting these theorists, we have arrived at more accurate decisions in other parts of our works. But the reason why we have gone in review through these philosophers is this, in order that we may receive also from them what they have already laid down as being first principles, and in what manner they fall in with the causes just enumerated. Undoubtedly do these appear to consider number to be a first principle, and, as it were, a material cause of entities, and as both their passive conditions and habits, and that the even and the odd are elements of number; and of these, that the one is finite and the other infinite, and that unity, doubtless, is composed of both of these, for that it is both even and odd, and that number is composed of unity, and that, as has been stated, the entire heaven is composed of numbers.

But others. of these very philosophers affirm that first principles are ten in number, denominated in accordance with the following co-ordinate series, namely: —
Bound. | Infinity.
Odd. | Even.
Unity. | Plurality.
Right. | Left.
Male. | Female.
Rest. | Motion.
Straight. | Crooked.
Light. | Darkness.
Good. | Bad.
Square. | Oblong.

In the same manner seems Alcmeon of Crotona to have formed his opinion; and this philosopher certainly, either from those just named, or they from this person, have derived this their theory for Alcmceon had reached the age of manhood when Pythagoras was an old man; but he enumerated his sentiments in a manner similar with the Pythagoreans. For he affirms that the greater portion of things human may be reduced to two classes, calling them contrarieties; not distinguished as these had distinguished them, but such as were of any casual sort whatever, as for example: —
White. | Black.
Sweet. | Bitter.
Good. | Bad.
Small. | Great

This philosopher, indeed, then, has indefinitely thrown out his opinions about the rest; but the Pythagoreans have declared both how numerous, and which these contrarieties are.

From both of these, therefore, it is possible to acquire thus much information, — that contraries are first principles of entities; but how numerous, and which these are, may be ascertained only from other speculators. How, indeed, in respect of the causes enumerated, it is possible to draw up a compendious application of their principles has not, in distinct terms, been clearly declared by them; but they seem to arrange the elements as in a form of matter: for of these, as inherent, they say that the substance consists, and has been moulded.

Of the ancients, therefore, indeed, — even of those who assert the elements of Nature to be many, — it is sufficient from these statements to examine into their intention.