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employed, like myself, in extending the elements of science. And those subjects which seemed best adapted for the employment of youth at the commencement of their philosophical studies, I have labored to present to them in this BOOK with faithfulness and assiduity in their selection, and with simplicity and intelligibility in their form and arrangement.

Of the difficulty of executing an acceptable compilation of the ELEMENTS OF THE SCIENCE OF MIND with analyses of the intellectual powers, in the order of their connection and dependence, it would be superfluous to reason with empirics who have not added one iota to literature or to science. But the philosopher and the critic know that judgment in selectior, perspicuity of style, and compression of argumentation, the great requisites of every writer who would not become dull from crudity of conception, nor obscure from prolixity of reasoning, are indispensable to give anciently-received truths and established modern discoveries those charms which shall fascinate readers in the purple bloom of youth. And in pleasing satisfaction will my mind now repose, if, among the unambitious pretensions of a compiler, the reasonings which support those truths shall be found to possess conciseness, and the illustrations of those discoveries no more expansion of proof than the different steps of their relative processes required; for, with youth whose mental faculties we would, by active discipline, invigorate, improve, and embellish, brevity is not less the soul of reasoning than of wit. Their knowledge, however, is not to rest on tarnished fragments struck off from splendid systems, nor on defective models the relics of doubtful institutes; but on the details of human knowledge, and such discipline of education as shall accustom them to exert their intellectual faculties, without preparation, and render them prompt in expedient, and active in resource.

Sufficient, however, has been said on Book Second, as well to show its high importance, as to satisfy every impartial reader, that, to have omitted it, or assigned to it any other place in the volume, would have evinced culpable neglect or capricious arrangement.

To have blended with the subjects in the Second Book those which constitute the Third, would have created a species of confusion, which, in elementary works, should always be avoided; and, besides, the relative importance this Book bears to the Second and the Fourth reciprocally, allotted to it that neutrality which makes it of easier reference to the numerous subjects that it may collaterally illustrate, or with which, in many instances, its materials may be directly conjoined. Nor is this. the only light in which Book Third may be viewed. If the subjects of which it is composed be considered abstractedly, then does the student enter upon disquisitions and analyses of separate branches of INTELLECTUAL PAILOSOPHY, of primary importance on his entrance upon philosophical studies. But

it is unnecessary to offer proofs for that which is clear as sunshine.

Of Book FOURTH, assigned to PURE Logic, I shall say a few words. But I premise, that of all arts, that surely is entitled to attention which pretends to tell us how we may improve and properly employ the UNDERSTANDING,--the faculty by which man is most eminently distinguished above the other creatures of this world, and by which, perhaps, he partakes most of the constitution of superior natures. Now, Logic is that art. Its professed purpose, as we have observed above, is to teach us the right use of reason, both in the investigation and in the communication of TRUTH;—to inform us how to introduce clearness and good order among our IDEAS ;–10 explain the OPERATIONS of the mind which are conversant about those ideas;

and by the proper exercise of which operations, we shall be least in danger of deviating into error.

The UNDERSTANDING is occupied entirely with knowledge the end of all science is to instruct us in knowledge; and the same end is pursued by all study, whether prudential, political, moral, or mechanical. In what way soever we exert and exercise our understanding, it is to obtain some information that we did not before possess; and the design of logic, considered as an art, is to hold forth the manner of attaining that knowledge with the greatest ease and expedition.

From these views of the nature and end of Logic, it is apparent, that it claims our attention as one of the first arts to which we should apply, in our progress towards knowledge, either as the best means of fortifying or of improving the understanding. The more acute the understanding is, the more successful will it be in the investigations of science. The less it is liable to err, the more certain and expeditious will be its progress in new and untried pursuits. The more we are acquainted with those sophistries which have misled other reasoners, the less liable shall we be to fall into similar mistakes. The better we understand the nature of the instrument which we employ, we may reasonably expect to be more expert and successful in its use. Every thing, then, in Logic, that does not contribute to improve the understanding, and to promote our progress in useful knowledge, deserves no attention; but every thing, on the other hand, that promotes these ends, cannot obtain more attention than it deserves.

Though no art ever gave occasion to so much idle research and fanciful refinement as Logic; though none ever so much bewildered the human mind, and repressed every useful exertion of the understanding, as that which pretended to enlighten and improve this faculty, and to guide it in the road to truth; though all the syllogism of the schools, after the thousand volumes that have been written on it, and after the employment of a series of ages to bring it to perfection, never enriched science

or art with one useful discovery,—we must not rashly conclude that these abuses furnish proofs of the general inutility, or insignificance, of Logic as an art.

As, then, the sophistry and absurdity with which Logic has been disgraced, are no valid objections against its use in a philosophical course of education, so neither is it to be contemned because we hear some men reason very justly without any acquaintance with its rules. There is in all mankind some natural logic, for it is one of those arts which may be learned by practice, with out the knowledge of theory.

One of the best methods of making progress in the art of reasoning, is actual practice, or the acquisition of the habit of examining a train of ideas constituting an argument; and of this branch of the art all men acquire some share by experience many men acquire a great deal ; but though long experience in sound reasoning may render us expert logicians, in the same manner as practice, without the knowledge of principles, may form eminent practitioners in any other art, yet this success will not justify any inference against the utility, or even the propriety of the theory. The end of all theory in the arts, is, to render us more methodical and reputable in their performance; and a knowledge of the principles on which, in this volume, the art of Logic is founded, can scarcely fail to facilitate the progress of youth in becoming good reasoners.

Of this they may be assured, if they have sufficient candor to admit there is such a thing as good reasoning, that there is no accomplishment or qualification any man can acquire more important than the art of reasoning well. Whether, then, youth shall become, in life, men of speculation or men of business, in every step they take, their rational faculties must be constantly exercised; and the subject of which we now speak is calculated entirely to render them expert and successful in that exercise.

The Fifth Book, which offers a sketch of “The Philosophy of Human Knowledge," seemed a necessary Appendix to the volume; but it was not my object, in the compass of a few pages, to enter upon a subject which I intend to publish in a separate work, as a sequel to my Grammars of Rhetoric and Logic.

And, for the purpose of initiating youth in the doctrines of the Philosophy of Mind, I have constructed, on this Grammar of Logic, a Book of “ Questions and Exercises," with a “ Key” to the same; as, in my humble judgment, no discipline is more successful in accomplishing its end, than that which reduces literature, philosophy, and science, to interlocutory discourse, conducted in the style and manner of a spirited dialogue. The ease with which the entire volume may be converted into “Dialogues on Logic and Intellectual Philosophy,” by means of its companion, the Book of Questions,” can only be equalled by the advantages

which youth ever derive from catechetical instruction, possessing the sprightliness of living language, and familiarizing the speakers to unpremeditated extempore discussion. If any thing can verify the observations contained in this Introduction, it must be the practice of the catechetical method which I now recommend

-a practice which distinguished the instructions of Socrates, which Plato has preserved in his Dialogues, and to which Cicero has reduced almost all his philosophical writings.


London, March, 1819.
















Of Abstract or General Terms.


Of General Conceptions....


Of General Conceptions formed by analyzing Objects. 73

Of the Operation of Generalizing..


General Conceptions formed by Combinations.



Association by essential Relations....


Accidental Relations or Sources of Association..


Of the Influence of Association on our various Judgments 96

As it affects the Decisions of Taste..


As it affects the speculative Opinions of Mankind.


The Influence of arbitrary Association, as it affects our

Moral Judgment.




Things obvious with regard to Memory.


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