[Footnote 682: "Topics," bk. i. ch. i.]
[Footnote 683: "Post. a.n.a.lytic," bk. i. ch. vi.]
[Footnote 684: "Ethics," bk. vi. ch. iii.]
[Footnote 685: Ibid., bk. vi. ch. xi.]
[Footnote 686: "Post. a.n.a.lytic," bk. i. ch. iii.]
[Footnote 687: Hamilton attempts the following mode of reconciling the contradictory positions of Aristotle:
"On the supposition of the mind virtually containing, antecedent to all experience, certain universal principles of knowledge, in the form of certain necessities of thinking; still it is only by repeated and comparative experiments that we compa.s.s the certainty; on the one hand, that such and such cognitions can not but be thought as necessary, native generalities; and, on the other, that such and such cognitions may or may not be thought, and are, therefore, as contingent, fact.i.tious generalizations. To this process of experiment, a.n.a.lysis, and cla.s.sification, through which we attain to a scientific knowledge of principles, it might be shown that Aristotle, not improperly, applies the term _Induction_."--"Philosophy," p. 88.]
The human mind, he tells us, has two kinds of intelligence--the _pa.s.sive_ intelligence (???? pa??t????), which is the receptacle of forms (de?t???? t?? e?d???); and the _active_ intelligence (????
p???t????), which impresses the seal of thought upon the data furnished by experience, and combines them into the unity of a single judgment, thus attaining "general notions."[688] The pa.s.sive intelligence (the "external perception" of modern psychology) perceives the individual forms which appear in the external world, and the active intelligence (the intellect proper) cla.s.sifies and generalizes according to fixed laws or principles inherent in itself; but of these fixed laws--p??ta ???ata--first thoughts, or _a priori_ ideas, he offers no proper account; they are, at most, purely subjective. This, it would seem, was, in effect, a return to the doctrine of Protagoras and his school, "that man--the individual--is the measure of all things." The aspects under which objects present themselves in consciousness, const.i.tute our only ground of knowledge; we have no direct, intuitive knowledge of Being _in se_. The noetic faculty is simply a _regulative_ faculty; it furnishes the laws under which we compare and judge, but it does not supply any original elements of knowledge. Individual things are the only real ent.i.ties,[689] and "universals" have no separate existence apart from individuals in which they inhere as attributes or properties. They are consequently pure mental conceptions, which are fixed and recalled by general names. He thus subst.i.tutes a species of conceptual-nominalism in place of the realism of Plato. It is true that "real being" (t? ??) is with Aristotle a subject of metaphysical inquiry, but the proper, if not the only subsistence, or ??a?a, is the form or abstract nature of things. "The essence or very nature of a thing is inherent in the _form_ and _energy_"[690] The science of Metaphysics is strictly conversant about these abstract intellectual forms just as Natural Philosophy is conversant about external objects, of which the senses give us information. Our knowledge of these intellectual forms is, however, founded upon "beliefs" rather than upon immediate intuition, and the objective certainty of science, upon the subjective necessity of believing, and not upon direct apperception.
[Footnote 688: "On the Soul," ch. vi.; "Ethics," bk. vi. ch. i.]
[Footnote 689: "Metaphysics," bk. vi. ch. xiii.]
[Footnote 690: Ibid., bk. vii. ch. iii.]
The points of contrast between the two methods may now be presented in a few sentences. Plato held that all our cognitions are reducible to two elements--one derived from _sense_, the other from _pure reason_; one element particular, contingent, and relative, the other universal, necessary, and absolute. By an act of _immediate abstraction_ Plato will eliminate the particular, contingent, and relative phenomena, and disengage the universal, necessary, and absolute _ideas_ which underlie and determine all phenomena. These ideas are the thoughts of the Divine Mind, according to which all particular and individual existences are generated, and, as divine thoughts, they are real and permanent existences. Thus by a process of immediate abstraction, he will rise from particular and contingent phenomena to universal and necessary principles, and from these to the First Principle of all principles, the First Cause of all causes--that is, to _G.o.d_.
Aristotle, on the contrary, held that all of our knowledge begins with "the singular," that is, with the particular and the relative, and is derived from sensation and experience. The "sensible object," taken as it is without any sifting and probing, is the basis of science, and reason is simply the architect constructing science according to certain "forms" or laws inherent in mind. The object, then, of metaphysical science is to investigate those "universal notions" under which the mind conceives of and represents to itself external objects, and speculates concerning them. Aristotle, therefore, agrees with Plato in teaching "that science can only be a science of universals,"[691] and "that sensation alone can not furnish us with scientific knowledge."[692] How, then, does he propose to attain the knowledge of universal principles?
How will he perform that feat which he calls "pa.s.sing from the known to the unknown?" The answer is, by _comparative abstraction_. The universal being const.i.tuted by a relation of the object to the thinking subject, that is, by a property recognized by the intelligence alone, in virtue of which it can be retained as an object of thought, and compared with other objects, he proposes to _compare, a.n.a.lyze, define,_ and _cla.s.sify_ the primary cognitions, and thus evoke into energy, and clearly present those principles or forms of the intelligence which he denominate "universals." As yet, however, he has only attained to "general notions," which are purely subjective, that is, to logical definitions, and these logical definitions are subsequently elevated to the dignity of "universal principles and causes" by a species of philosophic legerdemain. Philosophy is thus stripped of its metaphysical character, and a.s.sumes a strictly _logical_ aspect. The key of the Aristotelian method is therefore the
ARISTOTELIAN LOGIC.
Pure Logic is the science of the formal laws of thought. Its office is to ascertain the rules or conditions under which the mind, by its own const.i.tution, reasons and discourses. The office of Applied Logic--of logic as an art--is "to form and judge of conclusions, and, through conclusions, to establish proof. The conclusions, however, arise from propositions, and the propositions from conceptions." It is chiefly under the latter aspect that logic is treated by Aristotle. According to this natural point of view he has divided the contents of the logical and dialectic teaching in the different treatises of the _Organon_.
[Footnote 691: "Ethics," bk. vi. ch. vi.]
[Footnote 692: "Post. a.n.a.lytic," bk. i. ch. x.x.xi.]
The first treatise is the "_Categories_" or "Predicaments"--a work which treats of the universal determinations of Being. It is a cla.s.sification of all our mental conceptions. As a matter of fact, the mind forms notions or conceptions about those natures and essences of things which present an outward image to the senses, or those, equally real, which utter themselves to the mind. These may be defined and cla.s.sified; there may be general conceptions to which all particular conceptions are referable. This cla.s.sification has been attempted by Aristotle, and as the result we have the ten "Categories" of _Substance, Quant.i.ty, Quality, Relation, Time, Place, Position, Possession, Action, Pa.s.sion_.
He does not pretend that this cla.s.sification is complete, but he held these "Predicaments" to be the most universal expressions for the various relations of things, under some one of which every thing might be reduced.
The second treatise, "_On Interpretation_," investigates language as the expression of thought; and inasmuch as a true or false thought must be expressed by the union or separation of a subject and a predicate, he deems it necessary to discuss the parts of speech--the general term and the verb--and the modes of affirmation and denial. In this treatise he develops the nature and limitations of propositions, the meaning of contraries and contradictions, and the force of affirmations and denials in _possible, contingent_, and _necessary_ matter.
The third are the "_a.n.a.lytics_," which show how conclusions are to be referred back to their principles, and arranged in the order of their precedence.
The First or Prior a.n.a.lytic presents the universal doctrine of the Syllogism, its principles and forms, and teaches how must reason, if we would not violate the laws of our own mind. The theory of reasoning, generally, with a view to accurate demonstration, depends upon the construction of a perfect syllogism, which is defined as "a discourse in which, certain things being laid down, something else different from the premises necessarily results, in consequence of their existence."[693]
Conclusions are, according to their own contents and end, either _Apodeictic_, which deal with necessary and demonstrable matter, or _Dialectic_, which deal with probable matter, or _Sophistical_, which are imperfect in matter or form, and announced, deceptively, as correct conclusions, when they are not. The doctrine of Apodeictic conclusions is given in the "_Posterior a.n.a.lytic_," that of Dialectic conclusions in the "_Topics_," and that of the Sophistical in the "_Sophistical Elenchi_."
Now, if Logic is of any value as an instrument for the discovery of truth, the attainment of cert.i.tude, it must teach us not only how to deduce conclusions from premises, but it must certify to us the validity of the principles from whence we reason and this is attempted by Aristotle in the Posterior a.n.a.lytic. This treatise opens with the following statement: All doctrine, and all intellectual discipline, arises from a prior or pre-existent knowledge. This is evident, if we survey them all; for both mathematical sciences, and also each of the arts, are obtained in this manner. The same holds true in the case of reasonings, whether through [deductive] _Syllogism_ or through _Induction_, for both accomplish the instruction they afford from information previously known--the former (syllogistic reasoning) receiving it, as it were, from the traditions of the intelligent, the latter (inductive reasoning) manifesting the universal through the light of the singular.[694] Induction and Syllogism are thus the grand instruments of logic.[695]
[Footnote 693: "Prior a.n.a.lytic," bk. i. ch. i.; "Topics," bk. i. ch. i.]
[Footnote 694: "Post. a.n.a.lytic," bk. i. ch. i.]
[Footnote 695: "We believe all things through syllogism, or from induction."--"Prior a.n.a.lytic," bk. ii. ch. xxiii.]
Both these processes are based upon an _anterior_ knowledge.
Demonstrative science must be from things true, first, immediate, more known than, prior to, and the causes of, the conclusion, for thus there will be the appropriate first principles of whatever is demonstrated.[696] The first principles of demonstration, the material of thought, must, consequently, be supplied by some power or faculty of the mind other than that which is engaged in generalization and deductive reasoning. Whence, then, is this "anterior knowledge" derived, and what tests or criteria have we of its validity?
1. In regard to deductive or syllogistic reasoning, the views of Aristotle are very distinctly expressed.
Syllogistic reasoning "proceeds from generals to particulars."[697] The general must therefore be supplied as the foundation of the deductive reasoning. Whence, then, is this knowledge of "the general" derived? The answer of Aristotle is that the universal major proposition, out of which the conclusion of the syllogism is drawn, _is itself necessarily the conclusion of a previous induction, and mediately or immediately an inference_--a collection from individual objects of sensation or of self-consciousness. "Now," says he, "demonstration is from universals, but induction from particulars. It is impossible, however, to investigate universals except through induction, since things which are said to be from abstraction will be known only by induction."[698] It is thus clear that Aristotle makes _deduction necessarily dependent upon induction_. He maintains that the highest or most universal principles which const.i.tute the primary and immediate propositions of the former are furnished by the latter.
[Footnote 696: "Post. a.n.a.lytic," bk. i. ch. ii.]
[Footnote 697: Ibid., bk. i. ch. xviii.; "Ethics," bk. vi. ch. iii.]
[Footnote 698: "Post. a.n.a.lytic," bk. i. ch. xviii.]
2. General principles being thus furnished by induction, we may now inquire whence, according to Aristotle, are the materials for induction derived? What is the character of that "anterior knowledge" which is the basis of the inductive process?
Induction, says Aristotle, is "the progression from singulars to universals."[699] It is an illation of the universal from the singular as legitimated by the laws of thought. All knowledge, therefore, begins with singulars--that is, with individual objects. And inasmuch as all knowledge begins with "individual objects," and as the individual is constantly regarded by Aristotle as the "object of sense," it is claimed that his doctrine is that all knowledge is derived from _sensation_, and that science and art result to man (_solely_) by means of _experience._ He is thus placed at the head of the empirical school of philosophy, as Plato is placed at the head of the ideal school.
[Footnote 699: "Post. a.n.a.lytic," bk. i. ch. xviii.]
This cla.s.sification, however, is based upon a very superficial acquaintance with the philosophy of Aristotle as a whole. The practice, so commonly resorted to, of determining the character of the Aristotelian philosophy by the light of one or two pa.s.sages quoted from his "Metaphysics," is unjust both to Aristotle and to the history of philosophic thought. We can not expect to attain a correct understanding of the views of Aristotle concerning the sources and grounds of all knowledge without some attention to his psychology. A careful study of his writings will show that the terms "sensation" (a?s??s??) and "experience" (?pe???a) are employed in a much more comprehensive sense than is usual in modern philosophic writings.
"Sensation," in its lowest form, is defined by Aristotle as "an excitation of the soul through the body,"[700] and, in its higher form, as the excitation of the soul by any object of knowledge. In this latter form it is used by him as synonymous with "intuition," and embraces all immediate intuitive perceptions, whether of sense, consciousness, or reason. "The universe is derived from particulars, therefore we ought to have a sensible perception (a?s??s??) of these; and this is intellect (????)."[701] Intelligence proper, the faculty of first principles, is, in certain respects, a sense, because it is the source of a cla.s.s of truths which, like the perceptions of the senses, are immediately revealed as facts to be received upon their own evidence. It thus answers to the "sensus communis" of Cicero, and the "Common Sense" of the Scottish school. Under this aspect, "Sense is equal to or has the force of Science."[702] The term "Experience" is also used to denote, not merely the perception and remembrance of the impressions which external objects make upon the mind, but as co-extensive with the whole contents of consciousness--all that the mind _does_ of its own native energy, as well as all that it _suffers_ from without. It is evidently used in the Posterior a.n.a.lytic (bk. ii. ch. xix.) to describe the whole process by which the knowledge of universals is obtained. "From experience, or from every universal remaining in the soul, the principles of art and science arise." The office of experience is "to furnish the principles of every science"[703]--that is, to evoke them into energy in the mind. "Experience thus seems to be a thing almost similar to science and art.[704] In the most general sense, "sensation"
would thus appear to be the immediate perception or intuition of facts and principles, and "experience" the operation of the mind upon these facts and principles, elaborating them into scientific form according to its own inherent laws. The "experience" of Aristotle is a.n.a.logous to the "reflection" of Locke.
[Footnote 700: "De Somn.," bk. i.]
[Footnote 701: "Ethics," bk. vi. ch. xi.; see also ch. vi.]
[Footnote 702: "De Cen. Anim."]
[Footnote 703: "Prior a.n.a.lytic," bk. i. ch. xix.]
[Footnote 704: "Metaphysics," bk. i. ch. i.]
So much being premised, we proceed to remark that there is a distinction perpetually recurring in the writings of Aristotle between the elements or first principles of knowledge which are "clearest in their own nature" and those which "are clearest to our perception."[705] The causes or principles of knowledge "are _prior_ and _more known_ to us in two ways, for what is prior in nature is not the same as that which is prior to us, nor that which is more known (simply in itself) the same as that which is more known to us. Now I call things prior and more known to us, those which are _nearer to sense_; and things prior and more known simply in themselves, those which are _remote from sense_; and those things are most remote which are especially _universal_, and those nearest which are _singular_; and these are mutually opposed."[706] Here we have a distribution of the first or prior elements of knowledge into two fundamentally opposite cla.s.ses.
(i.) _The immediate or intuitive perceptions of sense,_
(ii.) _The immediate or intuitive apperceptions of pure reason,_
[Footnote 705: "Ethics," bk. i. ch. iv.; "Metaphysics," bk. ii. ch. i.; "Rhetoric," bk. i. ch. ii.; "Prior a.n.a.lytic," bk. ii. ch. xxiii.]
[Footnote 706: "Post. a.n.a.lytic," bk. i. ch. ii.]
The objects of sense-perception are external, individual, "nearest to sense," and occasionally or contingently present to sense. The objects of the intellect are inward, universal, and the essential property of the soul. They are "remote from sense," "prior by nature;" they are "forms" essentially inherent in the soul previous to experience; and it is the office of experience to bring them forward into the light of consciousness, or, in the language of Aristotle, "to evoke them from potentiality into actuality." And further, from the "prior" and immediate intuitions of sense and intellect, all our secondary, our scientific and practical knowledge is drawn by logical processes.