4. For the first and highest among the principia of each particular science. These, since they are the first and highest of all, cannot be discussed out of principia special and peculiar to any separate science; but must be discussed through the opinions commonly received on the subject-matter of each. This is the main province of Dialectic; which, being essentially testing and critical, is connected by some threads with the principia of all the various scientific researches.
We see thus that Aristotle’s language about Common Opinion or Common Sense is very guarded; that, instead of citing it as an authority, he carefully discriminates it from Science, and places it decidedly on a level lower than Science, in respect of evidence; yet that he recognizes it as essential to be studied by the scientific man, with full confrontation of all the reasonings both for and against every opinion; not merely because such study will enable the scientific man to study and converse intelligibly and efficaciously with the vulgar, but also because it will sharpen his discernment for the truths of his own science, and because it furnishes the only materials for testing and limiting the first principia of that science.
II. We will next advert to the judgment of Aristotle respecting these principia of science: how he supposes them to be acquired and verified. He discriminates various special sciences (geometry, arithmetic, astronomy, &c.), each of which has its own appropriate matter, and special principia from which it takes its departure. But there are also certain principia common to them all; and these he considers to fall under the cognizance of one grand comprehensive science, which includes all the rest; First Philosophy or Ontology — the science of Ens in its most general sense, quatenus Ens; while each of the separate sciences confines itself to one exclusive department of Ens. The geometer does not debate nor prove the first principia of his own science; neither those that it has in common with other sciences, nor those peculiar to itself. He takes these for granted, and demonstrates the consequences that logically follow from them. It belongs to the First Philosopher to discuss the principia of all. Accordingly, the province of the First Philosopher is all-comprehensive, co-extensive with all the sciences. So also is the province of the Dialectician alike all-comprehensive. Thus far the two agree; but they differ as to method and purpose. The Dialectician seeks to enforce, confront, and value all the different reasons pro and con, consistent and inconsistent; the First Philosopher performs this too, or supposes it to be performed by others, but proceeds farther: namely, to determine certain Axioms that may be trusted as sure grounds (along with certain other principia) for demonstrative conclusions in science.
Aristotle describes in his Analytica the process of Demonstration, and the conditions required to render it valid. But what is the point of departure for this process? Aristotle declares that there cannot be a regress without end, demonstrating one conclusion from certain premisses, then demonstrating those premisses from others, and so on. You must arrive ultimately at some premisses that are themselves undemonstrable, but that may be trusted as ground from whence to start in demonstrating conclusions. All demonstration is carried on through a middle term, which links together the two terms of the conclusion, though itself does not appear in the conclusion. Those undemonstrable propositions, from which demonstration begins, must be known without a middle term, that is, immediately known; they must be known in themselves, that is, not through any other propositions; they must be better known than the conclusions derived from them; they must be propositions first and most knowable. But these two last epithets (Aristotle often repeats) have two meanings: first and most knowable by nature or absolutely, are the most universal propositions; first and most knowable to us, are those propositions declaring the particular facts of sense. These two meanings designate truths correlative to each other, but at opposite ends of the intellectual line of march.
Of these undemonstrable principia, indispensable as the grounds of all Demonstration, some are peculiar to each separate science, others are common to several or to all sciences. These common principles were called Axioms, in mathematics, even in the time of Aristotle. Sometimes, indeed, he designates them as Axioms, without any special reference to mathematics; though he also uses the same name to denote other propositions, not of the like fundamental character. Now, how do we come to know these undemonstrable Axioms and other immediate propositions or principia, since we do not knew them by demonstration? This is the second question to be answered, in appreciating Aristotle’s views about the Philosophy of Common Sense.
He is very explicit in his way of answering this question. He pronounces it absurd to suppose that these immediate principia are innate or congenital, — in other words, that we possess them from the beginning, and yet that we remain for a long time without any consciousness of possessing them; seeing that they are the most accurate of all our cognitions. What we possess at the beginning (Aristotle says) is only a mental power of inferior accuracy and dignity. We, as well as all other animals, begin with a congenital discriminative power called sensible perception. With many animals, the data of perception are transient, and soon disappear altogether, so that the cognition of such animals consists in nothing but successive acts of sensible perception. With us, on the contrary, as with some other animals, the data of perception are preserved by memory; accordingly our cognitions include both perceptions and remembrances. Farthermore, we are distinguished even from the better animals by this difference — that with us, but not with them, a rational order of thought grows out of such data of perception, when multiplied and long preserved. And thus out of perception grows memory; out of memory of the same matter often repeated grows experience, since many remembrances of the same thing constitute one numerical experience. Out of such experience, a farther consequence arises, that what is one and the same in all the particulars, (the Universal or the One alongside of the Many), becomes fixed or rests steadily within the mind. Herein lies the principium of Art, in reference to Agenda or Facienda — of Science, in reference to Entia.
Thus these cognitive principia are not original and determinate possessions of the mind, nor do they spring from any other mental possessions of a higher cognitive order, but simply from data of sensible perception; which data are like runaway soldiers in a panic, first one stops his flight and halts, then a second follows the example, afterwards a third and fourth, until at length an orderly array is obtained. Our minds are so constituted as to render this possible. If a single individual impression is thus detained, it will presently acquire the character of a Universal in the mind; for, though we perceive the particular, our perception is of the Universal (i.e., when we perceive Kallias, our perception is of man generally, not of the man Kallias). Again the fixture of these lowest Universals in the mind will bring in those of the next highest order; until at length the Summa Genera and the absolute Universals acquire a steady establishment therein. Thus, from this or that particular animal, we shall rise as high as Animal universally; and so on from Animal upwards.
We thus see clearly (Aristotle says) that only by Induction can we come to know the first principia of Demonstration; for it is by this process that sensible perception engraves the Universal on our minds.[14] We begin by the notiora nobis (Particulars), and ascend to the notiora naturâ or simpliciter (Universals). Some among our mental habits that are conversant with truth, are also capable of falsehood (such as Opinion and Reasoning): others are not so capable, but embrace uniformly truth and nothing but truth; such are Science and Intellect (Νοῦς). Intellect is the only source more accurate than Science. Now the principia of Demonstration are more accurate than the demonstrations themselves, yet they cannot (as we have already observed) be the objects of Science. They must therefore be the object of what is more accurate than Science, namely, of Intellect. Intellect and the objects of Intellect will thus be the principia of Science and of the objects of Science. But these principles are not intuitive data or revelations. They are acquisitions gradually made; and there is a regular road whereby we travel up to them, quite distinct from the road whereby we travel down from them to scientific conclusions.
[14] Aristot. Anal. Post. II. p. 100, b. 3: δῆλον δὴ ὅτι ἡμῖν τὰ πρῶτα ἐπαγωγῇ γνωρίζειν ἀναγκαῖον· καὶ γὰρ καὶ αἴσθησις οὕτω τὸ καθόλου ἐμποιεῖ; also ibid. I. xviii., p. 81, b. 3, upon which passage Waitz, in his note, explains as follows (p. 347):— “Sententia nostri loci hæc est. Universales propositiones omnes inductione comparantur, quum etiam in iis, quæ a sensibus maxime aliena videntur, et quæ, ut mathematica (τὰ ἐξ ἀφαιρέσεως), cogitatione separantur a materia quacum conjuncta sunt, inductione probentur ea quæ de genere (e.g., de linea vel de corpore mathematico), ad quod demonstratio pertineat, prædicentur καθ’ αὑτά et cum ejus natura conjuncta sint. Inductio autem iis nititur quæ sensibus percipiuntur: nam res singulares sentiuntur, scientia vero rerum singularium non datur sine inductione, non datur inductio sine sensu.â€�
The chapter just indicated in the Analytica Posteriora, attesting the growth of those universals that form the principia of demonstration out of the particulars of sense, may be illustrated by a similar statement in the First Book of the Metaphysica. Here, after stating that sensible perception is common to all animals, Aristotle distinguishes the lowest among animals, who have this alone; then, a class next above them, who have it along with phantasy and memory, and some of whom are intelligent (like bees), yet still cannot learn, from being destitute of hearing; farther another class, one stage higher, who hear, and therefore can be taught something, yet arrive only at a scanty sum of experience; lastly, still higher, the class men, who possess a large stock of phantasy, memory, and experience, fructifying into science and art.[15] Experience (Aristotle says) is of particular facts; Art and Science are of Universals. Art is attained, when out of many conceptions of experience there arises one universal persuasion respecting phenomena similar to each other. We may know that Kallias, sick of a certain disease — that Sokrates, likewise sick of it — that A, B, C, and other individuals besides, have been cured by a given remedy; but this persuasion respecting ever so many individual cases, is mere matter of experience. When, however, we proceed to generalize these cases, and then affirm that the remedy cures all persons suffering under the same disease, circumscribed by specific marks — fever or biliousness — this is Art or Science. One man may know the particular cases empirically, without having generalized them into a doctrine; another may have learnt the general doctrine, with little or no knowledge of the particular cases. Of these two, the last is the wiser and more philosophical man; but the first may be the more effective and successful as a practitioner.