CHAPTER IX.

OF LOGIC AS RELATED TO OTHER MENTAL SCIENCES.

A DIVISION was early established in philosophy between the Logica docens and the Logica utens; the one concerned with the pure laws and forms of thought, the other with the application of thought to this or that objectmatter. The relations of the latter it is not my present purpose to examine. Every art or science, in so far as it contains reasonings on its own special objects, may be regarded as furnishing an instance of the Logica utens; and in this point of view Logic has no special affinity with one branch of knowledge rather than another. But in relation to the Logica docens, there are three branches of science, real or apparent, which, from community of object and method, as well as from historical connection, demand a more special consideration.

The three sciences in question are Grammar, Psychology, and Metaphysics. Rhetoric, from an association with Logic and Grammar in the medieval Trivium, might also be thought to have a special claim on our attention. But, in truth, Rhetoric is connected by community of object-matter rather with the art of Dialectic, as exhibited in the Topics of Aristotle and the Probable Syllogisms of the Scholastic Logic, than with the formal science as treated of in the present work. Its relation to the latter is only by way of application, inasmuch as logical forms may be applied in

rhetorical exercises; a relation which reduces it to a level with any other employment of the Logica utens. With Psychology, indeed, its connection is far more intimate, but on the opposite side from that by which the same science is related to Logic. Logic, as the science of the laws and products of the understanding, is related to Psychology through the medium of the speculative and discursive faculties. Rhetoric, as concerned with the movement of the will, is related on the side of the emotional and practical faculties, and is thus correctly described by Aristotle as an offshoot of Dialectic and Moral Philosophy.

On the other hand, Psychology, Metaphysics, and Grammar, are intimately connected with the faculties, the laws, and the instruments of the universal process of thought, a connection which has been recognized, with more or less clearness, from the origin of Logic to the present time. The Categories, from the days of Aristotle downwards, have been disputed ground between Logic and Metaphysics, and are treated of by the Stagirite himself in connection with both sciences. The treatise Tepi épuηveías, whose title, sorely misnomered by various translators, might be adequately expressed in English by, "Of Language as the interpretation of Thought," is, in the early portion, devoted to grammatical definitions and distinctions. Psychology also, though less prominently introduced, claims her share in the multifarious matter of the Organon; in the account of the processes of sensation, memory, and experience, as subsidiary to induction.

Were we indeed to start from the whole Organon of

1 For various interpretations of Interpretation, see M. St. Hilaire, De la Logique d'Aristote, p. i. ch. 10. The version given in the text corresponds to that by Isidore of Seville: " Omnis elocutio conceptæ rei interpres est: inde perihermeniam nominant quam interpretationem nos appellamus.”

Aristotle, as a uniform treatise on a single subject, it would be difficult to accommodate its contents to any modern classification of the mental sciences. But it may fairly be questioned whether even the authority of the philosopher himself can be adduced in support of such a proceeding. While we cannot help admitting, with Sir William Hamilton,' that the incorrect notions which have prevailed, and still prevail, in regard to the nature and province of Logic, are mainly to be attributed to the authority of the father of the science, it may be doubted how far that authority has been put to a legitimate use by his followers. The same eminent critic to whom we have just referred has observed, in another place, that there is required for the metaphysician not less imagination than for the poet; that it may, in fact, be doubted whether Homer or Aristotle possessed this faculty in greater vigor.2 The two authors here placed in juxtaposition may be compared in more respects than that of their mental powers. The influence of Homer in Poetry has been similar to that of Aristotle in Philosophy; yet, while, from the Father of Criticism to the present day, there has never been wanting a champion to maintain against all impugners the unity of design of the Iliad, and its exact relation to a beginning, a middle, and an end, the primary argument of this “ one entire and perfect chrysolite" has been almost as much disputed among critics as the question of the definition of Logic. Different portions of the poem have been pronounced genuine or spurious, according to this or that conception of the poet's design; and, finally, it has even been maintained that the model of all succeeding Epics is little more than a fortuitous concourse of atoms, the frag

1 Discussions, p. 141.

2 Reid's Works, p. 99.

ments of distinct rhapsodists. The Organon of Aristotle has had a similar fate. Various have been the conjectures concerning its design and method. Portions have been at different times regarded as logical, as grammatical, as metaphysical; nor have there been wanting critics to deny the genuineness of this or that part. The parallel might be carried further. The different portions of the Iliad are said to have been collected and arranged in the time of Pisistratus, about three hundred and forty years after the date assigned by Herodotus (rightly or wrongly) to the birth of the poet; and the writings of Aristotle are generally supposed to have received their present form and arrangement at the hands of Andronicus of Rhodes, a philosopher who flourished about three centuries later than the Stagirite. I am not indeed aware that any critic has been bold enough to maintain a thoroughly Wolfian hypothesis of the origin of the Organon; and yet there are not wanting grounds on which a not very different theory might be supported; not indeed as regards the authorship, but certainly as regards the unity of design of the work. The title by which the collected treatises are known is undoubtedly of recent origin; it is not found in Aristotle himself, nor in any of his earlier commentators; and, as far as existing evidence can determine, it appears not to have been in common use before the fifteenth century. The several treatises themselves are invariably mentioned by their author as distinct works under distinct titles; and even after the time of Andronicus, commentaries were generally written, not on the Organon as a whole, but separately on its constituent parts. If from the books we turn to the matters of which they treat, the result is the same. Logic, as the name of an Art or Science, does not once occur in the

1 St. Hilaire, De la Logique d'Aristote, vol. i. p. 19.

writings of Aristotle; and the cognate adjective and adverb are used in a peculiar and much more restricted sense than that which has subsequently been given to them. The names sanctioned by the philosopher himself, such as Analytic and Dialectic, are commensurate with portions only of the Organon; the division of Philosophy into Logic, Physics, and Ethics, adopted by the Stoics, and sometimes attributed (on questionable grounds) to Plato, receives no sanction from the Stagirite; indeed, he adopts a classification in many respects at variance with it, distinguishing theoretical philosophy from practical and productive, and dividing the first into three branches, Physics, Mathematics, and Theology.1

Leaving, then, altogether the question of authority, and adopting the formal view of Logic taken in the preceding pages as the only one which promises to secure for the science what it has so long needed, an exact definition and a determined field of inquiry, I shall proceed to examine the relation in which Logic, as thus exhibited, stands towards the cognate sciences of Psychology, Grammar, and Metaphysics.

Of Psychology something has already been said in the earlier portion of the present Essay. Logic deals with the products of the several thinking acts, with concepts, with judgments, with reasonings, as, according to certain as

1 Metaph. v. 1. Mr. Karslake (Aids, p. 10) speaks of the Organon as presenting so coherent a system, that the assertion that it contains a few only of Aristotle's logical works is doubtful. To me there appears little more of coherence than may naturally be expected in distinct writings of the same author on any question of Grammar, Analytic, Dialectic, or Rhetoric. And, as far as we can conjecture from existing evidence, it is most probable that the several books were written in the reverse order of that in which they are now arranged. See Burgersdyck, Inst. Log. Præf.; Fries, System der Logik, p. 15.