Commentary Aristotle Posterior Analytics
Lecture 20
How the first principles of demonstration are known by us b18. As to the basic premises, how they become known and what is the developed state of knowledge of them is made clear by raising some preliminary problems.
b20. We have already said that scientific knowledge through demonstration is impossible unless a man knows the primary immediate premises.
b23. But there are questions which might be raised in respect of the apprehension of these immediate premises: one might not only ask whether it is of the same kind as the apprehension of the conclusions, but also whether there is or is not scientific knowledge of both; or scientific knowledge of the latter, and of the former a different kind of knowledge; and, further, whether the developed states of knowledge are not innate but come to be in us, or are innate but at first unnoticed.
b26. Now, it is strange if we possess them from birth; for it means that we possess apprehensions more accurate than demonstration and fail to notice them.
b28. If, on the other hand, we acquire them and do not previously possess them, how could we apprehend and learn without a basis of preexistent knowledge? For that is impossible, as we used to find in the case of demonstration.
b30. So it emerges that neither can we possess them from birth, nor can they come to be in us if we are without knowledge of them to the extent of having no such developed state at all.
b32. Therefore, we must possess a capacity of some sort, but not such as to rank higher in accuracy than these developed states.
b34. And this at least is an obvious characteristic of all animals, for they possess a congenital discriminative capacity which is called sense-perception.
b36. But though sense-perception is innate in all animals, in some the sense-impression comes to persist, in others it does not. So animals in which this persistence does not come to be have either no knowledge at all outside the act of perceiving, or no knowledge of objects of which no impression persists; animals in which it does come into being have perception and can continue to retain the sense-impression in the soul:
a1. and when such persistence is frequently repeated a further distinction at once arises between those which out of the persistence of such sense-impressions develop a power of systematizing them and those which do not.
a4. So out of sense-perception comes to be what we call memory, and out of frequently repeated memories of the same thing develops experience; for a number of memories constitute a single experience. From experience again—that is, from the universal now stabilized in its entirety within the soul, the one beside the many which is a single identity within them all—originate the skill of the craftsman and the knowledge of the man of science, skill in the sphere of coming to be and science in the sphere of being. We conclude that these states of knowledge are neither innate in a determinate form, nor developed from other higher states of knowledge, but from sense-perception. It is like a rout in battle stopped by first one man making a stand and then another, until the original formation has been restored. The soul is so constituted as to be capable of this process.
a14. Let us now restate the account given already, though with insufficient clearness. When one of a number of logically indiscriminable particulars has made a stand, the earliest universal is present in the soul: for though the act of sense-perception is of the particular, its content is universal — is man, for example, not the man Callias. A fresh stand is made among these rudimentary universals, and the process does not cease until the indivisible concepts, the true universals, are established: e.g., such and such a species of animal is a step towards the genus animal, which by the same process is a step towards a further generalization. Thus it is clear that we must get to know the primary premises by induction; for the method by which even sense-perception implants the universal is inductive.
b5. Now, of the thinking states by which we grasp truth, some are unfailingly true, others admit of error — opinion, for instance, and calculation, whereas scientific knowing and intuition are always true: further, no other kind of thought except intuition is more accurate than scientific knowledge, whereas primary premises are more knowable than demonstrations, and all scientific knowledge is discursive. From these considerations it follows that there will be no scientific knowledge of the primary premises, and since except intuition nothing can be truer than scientific knowledge, it will be intuition that apprehends the primary premises — a result which also follows from the fact that demonstration cannot be the originative source of demonstration, nor, consequently, scientific knowledge of scientific knowledge. If, therefore, it is the only other kind of true thinking except scientific knowing, intuition will be the originative source of scientific knowledge. And the originative source of science grasps the original basic premise, while science as a whole is similarly related as originative source to the whole body of fact.
As to the basic premises. After showing how that which is the principle of demonstration in the sense of a middle comes to be known, the Philosopher now shows how the first common principles come to be known.
First, he states his intention.
Second, he pursues it, at: we have already said (100b20; [583]).
He says therefore first (100b18), that from what follows it will be clear concerning indemonstrable principles both how we come to know them and by what habit they are known. However, the plan we shall observe calls for us first to propose certain problems touching this matter.
Then, at: we have already said (100b20) he pursues his plan.
Concerning this he does two things.
First, he raises the problem.
Second, he settles it, at: therefore, we must possess (100b32; [588]).
First, he prefaces something from which the need for an inquiry of this kind is indicated.
Second, he raises the questions, at: but there are questions (100b23; [584]).
Third, he objects to a question, at: now, it is strange (100b26; [585]).
He says therefore first (100b20), that it has already been established above that nothing is scientifically known through demonstration, unless the first immediate principles are known beforehand. Therefore, in order to have scientific knowledge of demonstration, it is useful to know how the first principles are acquired.
Then, at: but there are questions (100b23) he raises three questions touching this knowledge of the principles.
The first question is whether the knowledge of all immediate principles is the same or not.
The second is whether there is a science of all immediate principles or of none; or is there science of some, and some other type of knowledge of the others.
The third question is whether the habitual knowledge of those principles comes to exist in us after previously not existing, or have they always been in us but escaped our notice.
Then, at: now, it is strange (100b26) he objects to the last question to which the others are ordered.
First, he objects to the second side, saying that it is unsuitable to claim that we have the habitual knowledge of these principles but they escape our notice. For it is obvious that those who have knowledge of the principles have a knowledge which is more certain than that which is acquired through demonstration. But knowledge through demonstration cannot be had such that it escapes the notice of the one having it. For it was established in the beginning of this book that a person who has scientific knowledge of something knows that it is impossible for it to be otherwise. Therefore, it is far less possible for someone having a knowledge of the first principles to have it escape his notice. Yet this absurdity would follow, if habitual knowledge of this kind were in us but escaped our notice.
Second, at: if, on the other hand (100b28), he objects to the other side. For if a person states that we acquire these habits or principles de novo after previously not having them, we are left with the further problem of how we can know and learn such principles de novo without some previous knowledge existing in us: for it is impossible to learn anything save from preexisting knowledge, as we have established above in regard to demonstration. But the reason why we cannot learn the immediate principles from preexisting knowledge is that preexisting knowledge is more certain, since it is a cause of certitude of the things which are made known through it. But no knowledge is more certain than the knowledge of these principles. Hence it does not seem that we can begin to know them, when previously we did not know.
Third, at: so it emerges that neither (100b30), he concludes from the above two arguments that it is neither possible always to have had the knowledge of these principles but it escaped our notice, nor possible that such knowledge is generated de novo in us to supplant a state of absolute ignorance in which no other habitual knowledge was possessed.
Then, at: therefore, we must possess (100b32) he solves these questions.
First, he solves the last one.
Second, he solves the first two, at: now, of the thinking states (101b5; [596]).
First, he solves a doubt.
Second, he shows the solution set down, at: let us now restate the account (101a14; [594]).
First, he proposes that some principle of knowing must preexist in us.
Second, he shows what it is, at: and this at “least” (100b34; [589]).
Third, he shows how from a preexisting principle of knowing we attain the knowledge of principles, at: so out of sense-perception (101a4; [594]).
He says therefore first (100b32), that there must be in us from the beginning a certain cognitive power that exists previously to the knowledge of principles, but not such that it is stronger as to certitude than the knowledge of principles. Hence the knowledge of principles does not come about in us from preexisting knowledge in the same way as things which are known through demonstration.
Then, at: and this at “least” (100b34) he shows what that preexisting cognitive principle is.
Apropos of this he posits three grades among animals.
The first of these is something which seems to be common to all animals, namely, that they have a certain connatural faculty [that is, potency, that is, power] for estimating about sense-perceptible things. This faculty, which is not acquired de novo but follows upon their very nature, is called sense.
Then, at: but though sense-perception (100b36) he mentions the second grade, saying that although sense is found in all animals, in some of them a sensible impression remains after the sense-object is removed, as happens in all the perfect animals. But in certain others this does not occur, as in certain imperfect animals; say in those which are not capable of progressive local movement. And it might perhaps be that in regard to some animals an impression remains in regard to certain sense-objects which are more vigorous, and not in regard to those which are weaker. Therefore, those animals in which no impression of sensible objects remains at all have no knowledge except when they are sensing. Similarly, in regard to animals in which such an impression is apt to remain, if it does not remain in them in the case of certain sensible objects, they cannot have any knowledge of them except while they are sensing. But animals, in which a trace of such an impression remains, are capable of having some knowledge in the mind beyond sense; and these are the animals which have memory.