III. The Prior Analytics, or, as it is more expressively named by the author, a treatise "concerning the syllogism." This is a masterpiece of skilful exposition; all the energy, vigour, and perceptive accuracy of his acute mind are here expended on a critical investigation of the possible forms of assertion, and of the conclusions which may or must result from their various relations, connections, and collocations. The internal nature and the external form of syllogistic reasoning are examined, described, and legislated for with an intellectual coherency and sustainedness rivalling the processes of mathematics. The whole doctrine of the syllogism is expounded with a felicity of exactness such as ought to have had more influence on subsequent logicians. The forms of syllogistics may have been by others more palpably, and effectively placed before men's minds, but the whole basis and ground of every valid form of reasoned (syllogized) thought is to be found in this tractate. The premises, assumptions, conditions, figures, relationship, laws, and modes of syllogism, are all specifically treated. The inductive form of finding premises, from which we may reason, is also noted and explained. It may here be as well to notice that while modern "logics" supply four forms or figures, Aristotle only considers three. This does not result from any incompleteness in the analysis of the syllogism contained in this portion of the organon, but from a misconception in the later logicians-who have constructed their figures according to the external position of the middle term in the premises, whereas Aristotle regarded only the internal relationships the various terms could assume. The fourth figure, while a possible, is an unadvisable form of syllogism; a defence of its validity as a form of reasoning is, however, contained implicitly in the doctrines of the prior analytics. As Reid has remarked, "Aristotle omitted the fourth figure, not through ignorance or inattention, but of design, as containing only some indirect modes, which, when properly expressed, fall into the first figure."

IV. The Posterior Analytics, or treatise on the principles of proof, is a highly important section of the "Organon.' Its chief object is to ascertain and explain how science is established through the conclusions arrived at by syllogistic reasoning. It treats of demonstration, the rules and conditions of certainty, as well as the general and particular principles of scientific thought, and its results-science. It shows how thought leads to thought by a conscious necessity; how, from the simplest elements of sensation, the orderly and sequent expositions of phenomena and their laws are worked out by the regulated activities of the mind; and how, from the presented concrete, the representative abstract is obtained, how sensations lead to hypotheses, and hypotheses to sciences.

One of the most remarkable parts of this treatise is that regarding the definition, in its power of determining the nature of a thing, or the meaning of a term. Language arises from, consists of, and contains the recorded though common-place inductions of mankind. Words express the impressions made on mind, and are the signs of

thoughtful observation. Their contents and meaning are made known by definition. Definitions are concentrated knowledge; they are statements of the limitations which the intellect perceives in ideas, and the means of fixing the signification of any given word or idea. Aristotle strives to prove that the forms of thought correspond with, and are determined by, the forms of things; and endeavours to test the logical by the real. The functions and the efficiencies of the intellect appear to him not to be excited only, but compelled to certain modes of activity by the outward and ordinary manifestations of phenomena. He had not reached the Kantean abstraction of form and matter now common among logicians, but believed that the instinctive necessities of human reason lead men to measure thought by things, and to test the accuracy of these thoughts by a comparison with the material phenomena of which they were, or seem to be, the explanations. His logic is not a bare, formal skeleton or scaffolding, into which thought uselessly builds itself, as a means of exercising and educating itself. It sought to insinuate itself into nature, to permeate the whole fabric of creation with an active intelligence; and this intellective faculty, when it returned into itself again, he supposed would bring into the inner recesses of the mind the results of its investigations, and tell the secrets it had learned in its excursive and discursive survey and critique of the various material forms and elements it had examined and operated on.

A far deeper and more abstruse purpose dwelt in the logic of Aristotle than that of the mere formal unfolding of the contents of the mind's own ideas, and in this treatise especially he supplies an outline of a metaphysic as well as a science of apodictic or demonstrative reasoning. Demonstration is, with Aristotle, not only a series of necessarily connected thoughts, a detailed and consecutive process of argumentation; it is also, in some respects, an interpreter of the laws of the understanding, inasmuch as it treats of truth as it affects the intellect, simply and apart from the will; for when we seek to influence at one effort both the understanding and the will we employ rhetorical, not logical phraseology. Science, as it was thought of by the earlier philosophers, was very different from the view we commonly take of it in our day. The results of observation and experiment, theorized upon, and compared in their ultimate inferences with the realities of nature, life, or mind, and thereafter systematically collocated into a series of progressively advancing statements or truths, we now denominate science. By the elder thinkers, science meant positive, trustworthy knowledge; hence it was essential with them that it should rest upon and emerge from truths, not only known, but known to be incapable of being other or else in fact, necessary truths. The definition thus became the keystone of science; and Aristotle's ideas of induction permitted full scope for acquiring a knowledge of matters of fact from experience, and so of founding upon inductive truth a series of demonstrations which would have constituted a science. But the ancient notion of science obscured his own mind, as well as that of his

disciples, and this form of thought has been less developed in scholastic logic and by the continuators of the syllogistic system than it might and ought, so that an unjust opprobrium lies upon the memory of Aristotle, and his logic has been contrasted with and opposed to that of Bacon, when in reality the Verulamic induction is a complement and a supplement to the Stagyric. In the latter it is as emphatically taught as in the former, that "we attain certainty in all things through syllogisms, or by induction;" and "we learn either by induction or demonstration, and demonstration proceeds from generals, but induction from particulars." It is scarcely true that Aristotle canonized theory as the highest effort and aspiration of the soul, or that he set aside methodical experiment and inventive investigation; though, in his age, the fashion of philosophic thought did indeed tend towards talk, dispu tation, and words, rather than to experiment, invention, and discovery, and Aristotle was not wholly exempt from the errors of his time. It might, however, be articulately proven that he saw the essential truth and utility of induction by a collection of passages, of which the following may, as crucial instances, suffice: "Induction is progress from the particular to the universal;" and, "Induction is very persuasive, clear, and intelligible to sense, and more in vogue among the multitude, though the syllogism has more force, and is more effective against opponents in argument." "It is manifest, therefore, that it is necessary for us to know the prime elements by induction, for perception through this also produces the universal in the mind."

Induction with him is, indeed, more a means of definition-a mode of arguing-than a method of inquiry into facts and evidence; but this is only an accident of the state of philosophy in his age. There is nothing in his theory of demonstration really opposed to the Baconian induction; and there are many parts of his doctrine which require development in the inventive element to acquire the definite validity of a science. No specimens of the inductive logic are extant more strictly accordant with the Baconian view of a groundwork of experience, and a constant testing by experiment or reference to observation, than the rhetoric, the poetic, and the ethics of that philosopher whom common minds stigmatize as the corruptor of science by syllogism, and the inventor of false methods of thought The Posterior Analytics are a profound and scientific exposition of the method of demonstrative reasoning,-of the disciplinary processes of thought for attaining truth, and communicating it to the understanding.

V. The Topics.-A treatise on the principles and proofs by which we can dispute about things, and an analysis of the various probabilities, likelihoods, and experiences from which arguments may be derived. It contains exquisite dissections of the forms and appliances of dialectics, for the purpose of teaching "a method by which a man may be able to reason with probability and consistency on any question that may arise;" it is a compendium of controversy, or the art of attacking or defending any given thesis by such arguments

as may appear to justifyor refute it,-such as general opinion, common practice, the authority of skilled or eminent men, the comparison of likelihoods, and the effects these ought to have upon the mere intellect of man. In these objects it comes very near the margin of rhetoric, and in some sort might be said to be included under it, were it not that dialectic, in the Aristotelian sense, eliminates from the problem of the Topics the moral influences or effects of controversy, and merely aims at the imparting of intellectual skill in that

one art.

The eight books of the Topics are more wonderful for the fertility, ingenuity, and extent of reflective skill they display, than for their methodicality. They constitute a grand storehouse of acute distinctions and singularly clear and judicious applications of the pure force of the intellect to the investigation of the specific arguments the mind can supply in the conducting of controversy. The teachings of these books are so minute and diffuse, so exact and intimate, so varied, and so punctiliously distinct, that analysis, or the giving of any general idea of the many aphorismic instructions they contain, is impossible. The means by which, so far as the mere power of the mind itself affords them for acquiring victory in debate, are here described with a fulness, ease, and pointedness, which could hardly be excelled. Hints are given for the attainment of arguments, and aids are supplied for conducting controversies, discussions, and judicial investigations, which are quite capable of being highly useful, and which might easily be collocated so as to afford a far higher than a dialectic victory,-even one over the intricacies of nature and the mysteries of mind. The strongly systematic mind of Aristotle, though it has put forth all its energies in finding the materials for a marvellously planned science of controversial argumentation, has not been successfully applied to the arrangement of the various items, on the thinking out of which so much care has been expended. The eighth book of the Topics is an elaborate series of directions for the conducting of disputes, in which the duties, trickeries, plausibilities, and flimsities of querist and respondent are noted and explained, and full instructions are given for the training of the mind to skill in dialectic discussion. Nor is this the useless and barren art which some wiseacres proclaim it to be. It calls out, trains, and exercises the most potent faculties of the soul. There is scarcely anything "in regard to which notions cruder, narrower, or more erroneous prevail, than in regard to disputation, its nature, its objects, and its ends; nay, I make bold to say, that by no academical degeneracy has the intellectual vigour of youth lost more, than through the desuetude into which, during these latter ages, disputation as a regular and daily exercise in our universities has fallen." In this opinion, uttered by Sir William Hamilton, we wholly coincide; and we believe that the exercised culture arising from the contests of mind with mind provided for in Aristotle's Topics, would be a great safeguard against the waveringmindedness so common in our day. So long as we believe in "the superior utility of disputation as an exercise, and the superior

utility of exercise in general as a mean of intellectual development," we must regret the neglect with which logicians have hitherto treated the books of the Topics of Aristotle.

VI. On Sophisms, or Fallacies.-The hypocrisy of thought, like the hypocrisy of life, produces evil consequences; and it is no less needful to guard against the latter than the former,-nay, rather more requisite in the case of falsity of idea, for out of it the other hypocrisy most frequently develops itself. Deceptive thought and deceptive speech are both too common in the world. To know the tricks of men and the vagrancy of our own minds, would greatly aid us in guarding against the mistakes and errors into which we may be led by over-confidence in ourselves or others. The object of the book on Sophisms is to make an investigation into the sources of error, the means of detecting it, and the processes by which the mind may be taught to test and assay the thoughts propounded for its acceptance. Truth is man's only sure defence and dependence. If we rely on the false, we must be disappointed; truth alone places us within an impregnable fortress,-alone supplies safety, happiness, and honour. Thought is seldom procurable in unadulterate perfectness, and counterfeits of it are often manufactured. These ought to be instantly swept out of the circulation of thought, and therefore means for their detection must be planned and employed. To this work Aristotle sets himself right earnestly in the treatise with which he closes the round of logical instruction and finishes the Organon. It is a production of a most brilliant character, and the author's cleverness as a detective of impostors among thoughts has seldom found a parallel. Scarcely a possible form of faulty thought escapes him; and the devices he uses for gaining the triumph of truth are not even now, in their own place, to be excelled.

To reduce into strict classifiability the various possibilities of error to which the mind in thinking was liable, was of itself a grand idea, -such as no one, possessed of less of the scientific and systematizing genius of Aristotle, could have dreamed of, much less accomplished. Yet there are very few modes of causing an erroneous impression to arise in the mind of any one, of suggesting or expressing an argument so as to be likely to deceive or have all the effects of deception, and of giving an appearance of plausibility or probability to a false or incorrect argument, which he has not analyzed and exposed, as well as expounded, with a perspicuity and keenness of vision which render a student inexcusable if he be taken unawares by unsound or indecisive reasoning. Ordinary works on logic now treat so fully of fallacies, their nature, causes, classes, forms, and detection, that it does not seem requisite here to say more than that the Aristotelic treatise on sophistical proofs has been but little improved in acuteness, expressiveness, or classification, by the subsequent exponents of the science-many as they are of right thinking.

It is usual in our day to prefix to the Organon the Introduction of Porphyry, regarding genus, species, difference, property, and accident, their laws, relations, and implications; and most of the Logics of the present day incorporate less or more of the doctrines