SPECTATOR'S LIBRARY.

MENTAL SCIENCE, A System of Logic, Ratiocinative and Inductive : being a connected View of the Principles of Evidence, and the Methods of Scientific Investigation. By John

Stuart MM. In two volumes. Second edition Parker. CoLortur. Surruratera, Philip Musgrave ; or Memoirs of a Church of England Missionary in the North Ame- rican Colonies. Edited by the Reverend J. Abbott, A.M. (Murray's Home and

Colonial Library.) Murra. }tallow, The Wbutante ; or the London Season. By Mrs. Gore, Author of "Mothers and

Daughters," ece. &c. In three -volumes. Bentley.

MILL'S SYSTEM OF LOGIC.

OF the first edition of this profound and admirable treatise, when pub- lished three years ago, no notice appeared in our columns ; an omission which we now willingly repair.

In one respect, indeed, the postponement is the less to bri. regretted as it enables us to express our gratification that a second ellition should have been called for within the space of three years. So overwhelming is the pressure of ephemeral publications at this moment upon every one's time and attention, and so completely is the palate of readers fashioned to receive nourishment adapted exactly to the point of present time—unripe yesterday, yet stale tomorrow—that the attention which has been at. tracted to Mr. Mill's work is not less surprising than satisfactory. The book is, from beginning to end, a tissue of serious, solid, and coherent thought—strictly permanent in its application fitted on to no sentiment or interest of a temporary character—neither falling in with that extreme speciality of research and predominance of fascinating illustration to which the scientific men of our day chiefly confine themselves, nor muti- lated so as to suit that combination of false glare and obscurity in which so many teachers of youth exhibit nature to the views of their pupils. It has all the merits which a work strictly general and scientific ought to have, and all the attractions which it can have consistently with being really as well as professedly instructive. For the reader will nowhere find truths of so much generality, and in many instances of so much novelty, unfolded in a style more unaffected and perspicuous, or better sustained by apposite though not over-multiplied illustrations. Of the steps essential and subsidiary to scientific investigation of the true se- curities for scientific correctness, and of the various Misleading causes which so frequently land men in scientific error, Mr. Mill's book gives information at once more ample and more intelligible than any work with which we are acquainted.

We shall try to convey to our readers an idea of the point of view in which Mr. Mill looks at science, as well as of the principal topics dis- cussed in his volumes; premising that, to do this well in our limited space is all but impossible, seeing that his speculations are in a high, degree continuous and indisoerptible, and can seldom or never be described in language more concise than that which he has himself chosen.

However elaborate may be the title which an author bestows upon his own work, the public will not take the trouble of speaking of it under, any denomination longer than a binomial; and Mr. Mill's book is ac- cordingly styled only Mill's System of Logic," omitting all those ex- planatory adjuncts which he has himself introduced into 'the titlepage. This is calculated to convey a very inadequate idea of the ground whit% his speculations cover. It leads to the supposition that we are to be in- troduced to a new treatise on what is commonly known by the name of Logic, or the School Logic—to a treatise coextensive with Archbishop Whately's "Elements of Logic," or with any one of the excellent scholastic manuals on the same subject. To explain everything which is essential and valuable in the School Logio, does indeed form a part, but only a part, of Mr. Mill's purpose. It occupies if we include the ne- cessary preliminaries and accessories, the larger half of the first volume. As an exposition of those elementary processes which are necessary to general reasoning, it finds its place at the beginning of his work ; but the reader is carried thence into a fir wider range of thought: he is conducted through the full analysis of the inductive and deductive methods' with many illustrations derived from different subjects to which each has been applied, and valuable comments upon the scope, the limits, and the future availability of each. The operations subsidiary to in- duction—such as observation, abstraction, naming, the requisites of a philosophical language, classification, &o.—are treated at considerable length. The different varieties of fallacies are exhibited and dealt with in the second volume : this is a subject which has belonged to logicians from Aristotle downwards, though it has never been handled in a spirit more ample and philosophical than by our author. Lastly, the process of scientific inquiry, as applied to the moral sciences apart from the phy- sical, is considered ; and reason is shown for studying the former chidy through the deductive method, in consequence of the highly complex agencies which their phaznomena exhibit. Mr. Mill's System of Logic thus contains a far more copious assemblage of materials, and a greater breadth of philosophical survey, than that des- cription would naturally be understood to imply. His observations on me- thod are calculated to interest as well as to benefit every student both of the moral and physical sciences. He goes over not only the same ground as Archbishop Whately, (" Elements of Logic,") but also substantially the same as Sir John Herschel, ("Discourse on Natural Philosophy,") and M. Auguste Comte, (" Traite de Philosophic Positive"). By the last work especially, replete as it is with original and comprehensive views on scientific method generally, Mr. Mill has largely profited ; combining the best part of the instruction supplied by M. Comtes profound mastery of the philosophy of physical science, with notions sounder (we think) than the latter as to the science of man and society.

In determining the province of Logic, Mr. Mill builds upon and en- larges Archbishop Whately's definition, that it is the science as well as the art of reasoning : but he gives to the word reasoning a larger sense • than the Archbishop—not so as to mean exclusively synogizing, but so- as to mean generally, "inferring any assertion from assertions already admitted"; in which latter sense, induction is not only one branch of reasoning, but is in fact the process into which everything entitled to

he called inference must be ultimately resolved. Truths being known to Gs in two ways—some through intuition or consciousness, others by inference from other truths previously known—the business of Logic is exclusively with the latter. By far the larger portion of our knowledge consists of inferences from truths previously known the antecedent data being sometimes put into the form of general propositions, sometimes standing as clusters of particular observations and per- ceptions. This transition of the mind from premises to a conclusion, which is of daily occurrence and unavoidable necessity in every relation of life, and which pervades alike the whole subject-matter of our know- ledge, falls under the province of logic, to furnish principles and rules for testing the correct performance of the process. There are conditions of good and sufficient proof to which every mind conforms, knowingly or unknowingly, in all cases of right judgment, and to which also investi- gations in all the particular sciences must conform : that logic, in deter- mining these, becomes the critic and censor of all the other sciences— "the science of science itself." Not only the process of proceeding from the known to the unknown, but also all operations of the under- standing auxiliary to it., all instruments or aids employed in it, and all hinderanees tending to baffle or falsify it, become also portions of the domain of logic. On this ground, naming, definition, and classification, come in as necessary subjects of study to the logician, and are discussed accordingly in Mr. Mill's volumes.

In the introduction, wherein this definition and province of logic is assigned, Mr. Mill takes much pains to distinguish this science from Transcendental Mektphysics, and seems even to think the two so com- pletely distinct, that views analogous to his own on the subject of logic might be held by metaphysicians of the most opposite schools—by Hart- ley, Reid, Locke, and Kant. If we rightly apprehend his opinion on this point, we cannot subscribe to it. We think that his logical specula- tions have a decided tendency favourable to those who narrow, and hostile to those who widen, the circle of the so-called intuitive truths—a tendency to disallow indirectly many of those truths or laws of belief for which authority is claimed altogether independently of experience. In his reasoning against Mr. Whewell (book II. chap. 5,) on the subject of Demonstration and Necessary Truths,- and in his chapters on Fallacies, (book V. chap. 3,) especially on Fallacies of Simple Inspection, we find some of the most valuable observations of Mr. Mill's work, in which he controverts the tendency of Mr. Whewell, Descartes, and others, to give objectivity to laws of the mind, and to suppose that what is true of our ideas of things must be true of the things themselves, or that what we may be able or unable to conceive is to be taken as a test or limit of the realities of nature. It. is the recognition of these mental necessities of belief, imposed upon the coarse of phmnomenal facts as conditions either imperative or supplementary, which constitutes the main difference be- tween the school of Locke and that of the Scotch and German meta- physicians generally. A good system of logic will not, we think, be found capable of allying itself with an erroneous system of metaphysics.

• Mr. Mill's first book treats of Names—of Things denoted by Names (in scholastic phraseology, the Predicaments)—of Propositions—of Attri- butes predicable of a subject, considered with reference to the class in which that subject is ranked (the five Predicables)—and of Definition. It travels over that ground which in a treatise of the School Logic is con- sidered necessary to prepare the reader for the doctrine of the Syllogism. It will be found to lay all the foundations of ratiocinative speech, and to take account of those distinctions, for the most part both real and valu- able, which determine the technical nomenclature of the schoolmen; di- vested, however, of that narrowness and imprisonment within grammati- cal forms, which in their case was rendered unavoidable, partly by their exclusive use of one language, partly by the small compass of well-con- ducted positive investigation then open to be studied. The integer of logic—that alone which can be believed or disbelieved, proved or dis- proved—is the proposition, with its predicate, subject, and copula : names are the fractions of a proposition, though many of them are significant by themselves : the syllogism is a combination of propositions. Into the various distinctions of names Mr. Mill enters at some length,—l. General and Individual; 2. Abstract and Concrete; 3. Connotative and Non- Connotative ; 4. Positive and Negative; 5. Relative and Non-Relative. The distinction which stands third he dwells upon emphatically, and with great reason, as of supreme importance in reference to precise thought. The word "connote" is a genuine term of the schoolmen, employed, how- ever, in a sense somewhat different from that which they affixed to it. A name denotes the subject of which it is predicated : it connotes those attributes, or those events, on account of which it is given to the subject. To have an express word (connote), which marks the relation in which a general name stands to these attributes or events on account of which it is given, will be found all but indispensable when we come to disentan- gle that confusion which renders common language so inadequate an in- strument for the philosopher. The real signification of a concrete general name (such as "man," "horse," " black,' ) consists in the attribute or attributes which it connotes : these always are, or always may be, defi- nite; while the number and diversities of the subjects, denoted or entitled to be called by the name, is endless. To understand what is meant by the connotative force of a name, will be found especially necessary in order to follow Mr. Mill's chapter re- specting the Theory of Propositions. In that chapter he discusses both the opinion of the Conceptualists—that a proposition is the expression of a relation between two ideas—and that of Hobbes and the Nominalists, who consider it as the expression of an agreement or disagreement be- tween the meanings of two names : he shows that the former of these two opinions is erroneous, the latter inadequate. All propositions, which are not purely verbal, are affirmations or denials of one or other among five different kinds of matters of fact,—existence, order in place, order in time, causation, and resemblance; One of these the is either affirmed or denied respectingtsome that or phsenomenon, or respecting some object the unknown source of a fact or phenomenon. Apart from what are called Essential 'Propositions, (which are in truth purely verbal, and in which the predicate connotes or implies only something which is also connoted by the subject,) all non-essential or accidental propo- sitions give as information respecting matters of fact : we learn that the attributes connoted by the predicate are conjoined with those connoted by the subject. " All men are mortal " means that the attributes implied (connoted) by the word man are always accompanied by the attribute mortality—in other words, that they are evidence or proof of its being present. Considered in this evidentiary character, the proposition may be considered as "a memorandum for practical use"; and it becomes avail- able as a formula for guiding our future inferences in particular cases.

Of the two chapters of Mr. Mill respecting the Predicables and re- specting Definitions, both contain matter novel and instructive, and both rectify misconceptions which have misled thinkers as acute as Hobbes and as recent as Archbishop Whately. In both it is shown that a dis- tinction much dwelt on by the Schoolmen, and afterwards totally rejected by the Nominalists, is at the bottom real and well founded, though it was erroneously stated and explained by its primitive authors. The expla- nation given, especially, respecting what they called the definition of a thing, as distinguished from the definition of a name, is valuable as it elucidates the primitive source from which geometrical theorems are de- rived. The definition of a thing is a definition and something more: it tacitly postulates the existence of a thing having the property described in the definition; and it is from the fundamental property thus assumed that other properties of the thing are deduced. This chapter on Defi- nitions is of much value, inasmuch as it forms a necessary preparation for the valuable chapter respecting Demonstration and Necessary Truths, wherein it is shown (against Mr. Whewell) that geometrical theorems are no otherwise necessary troths than as necessarily following from the assumption of certain fundamental hypotheses, and from the application of the truths asserted in the axioms—those axioms being themselves generalizations from experience.

After having thus explained Propositions and their constituent parts, Mr. Mill next proceeds to put together these propositions into a Prot: and to consider under what conditions premises are to be considered as sufficient and a conclusion as being proved. The Syllogism here receives in its diversities of mode and figure, an explanation long enough to be understood without going much into.detail : but what is of much greater importance, the place which it occupies in the entire process of reasoning, and the logical value to whioh it is entitled, are appretiated in a manner which to us appears at once novel and just. A syllogism, however com- plete in mode and figure, does not represent the real step which the-mind makes in a good and conclusive inference-,•-it does not give the jump from known to unknown in which that inference consists. The two premises of a syllogism do not constitute the genuine grounds on which we assent to the conclusion, or by which we must defend it if disputed: the minor premiss is indeed an essential portion of those grounds, but it is not the major premiss which constitutes the remaining portion. That major premiss is itself an inference, of the same nature as the conclusion, only of vastly greater extent—an inference resting upon previous matter of evidence furnished by observed particular facts. This previous matter of evidence, which suffices of itself to prove the major premiss, is also the real supplementary evidence, which, when taken in conjunction with the minor premiss, proves the conclusion. The major premiss is a for. mule describing generally what inferences a given mass of evidence is understood to warrant : if a particular case appears which comes under this general description, we may indeed recur to the formula to save the trouble of again going through the whole mass of evidence from which it resulted; but we cannot produce the formula as being itself evidence to prove any ulterior conclusion. When this point is adverted to, we can appretiate more clearly the frequent objections taken by those who impugn the syllogistic process as useless and founded in delusion ; objections which its defenders have never yet successfully combated. The major premiss doei3 incontestably involve a pet itio principii, as the objectors have contended—it assumes the con- clusion which is supposed to be in dispute, only assuming along with it a great deal more. If you are called upon to prove that a certain man, A B, is mortal, (he pretending to possess, like the Comte de St. Germain in the last century, an elixir of life,) the person who requires this to be proved will certainly not allow you to begin by stating, as the first part of the proof, that "Every man is mortal"—the major premiss of the well-known syllogism. You will be forced to produce to him what is, after all, the genuine, appropriate evidence in the particular case before you—the innumerable instances of persons, like Numa and Ancus, who, having been alive, have died, &c. It is from these matters of fact, alone and unaided, that we draw the general inference, "Every man is mor- tal": it is upon these matters of fact, conjoined with the minor premiss of the syllogism, (A B is a man,) that we draw the particular inference, A B is mortal. Knowing all that heap of particular facts which consti- tute the evidence for the major premiss, we might draw our inference to the new particular case, A B, without introducing the major premiss at all: we not only might do so, but in very many cases we do so actually. With unlettered men, however acute, it is probably the usual mode of inference; and with the lower animals, who have not the use oflanguage, it is the only mode. But while Mr. Mill thus shows that the major premiss of a syllogism contains no part of the evidence on which the conclusion rests, and will therefore be unavailable as proof wherever the conclusion is really and bona fide denied and disputed—he also shows that the interposition of this step is of great value for the correct performance of the real process of inference, whereby the mind steps from the known facts constituting matter of evidence to the new fact, unknown or disputed, which that evidence proves. If the correctness of the inference, stated in general

terms, be disputed, the inference in the particular case cannot be main- tained: and though the major premiss does not form part of the evidence by which the conclusion is proved, still, if you dispute it, the conclusion fails. To state in a general formula, ready for future application, the full extent of inference which the evidentiary facts Wore us warrant, is indispensable not less to any wide range than to any assured correctness of reasoning : the inference thus stated constitutes a memorandum or record for future use, which we have only to interpret when the occasion arises.

In our brief space, we can convey only a very imperfect conception of that which Mr. Mill has most perspicuously set forth in the second, third, and fourth chapters of his second book. He has there, we think, stated the case between the impugners and the defenders of the syllogism more clearly than we have ever seen it elsewhere. According to his analysis, all ratiocination is resolvable ultimately into induction : the matter of evidence consists always of observed particular facts, from which we draw an inference either with regard to some new particular case before us, or in general terms, ready to be interpreted and applied to any future case which may arise. That every generalization from experience is not simply a statement of fact, but also includes an inference from those facts extending to an undefined number of future cases, is an important truth which this work brings out and insists upon. Mr. Mill's third book goes into the explanation of the Inductive Pro- cess, in its refined and complicated as well as in its simple applications.

The four distinct methods of experimental inquiry are explained,—the method of Agreement, the method of Difference, the method of Residues, and the method of Concomitant Variations. The reach and advantages of each of these methods is unfolded, together with the particular subjects of inquiry for which each is most available; and examples of each are subjoined from the best specimens of recent physical philosophy. To these are added a review of the Deductive Method ; where, having occa- sion to study complex effects resulting from the concurrent action of many causes, and having ascertained by a previous induction the law of each of these causes separately, we reason from the simple laws to the complex cases, and are enabled to anticipate what we afterwards verify by specific experience. Not the least valuable portion of this book consists in the care which is taken to clear up the chief postulates and fundamen-

tal assumptions involved in inductive research : the analysis of causation, lams of nature, explanation of lams of nature &c., will be found

highly instructive. So true it is that the familiarity of a word to the tongue and the ear is quite consistent with the loosest and vaguest con- ception of its meaning.

The fifth book, on Fallacies, recognizes and passes in review five dif- ferent classes,—fallacies of Simple Inspection, of Observation, of Gene-

ralization, of Ratiocination, of Confusion • reasons being shown why this classification is adopted. There is nothing more remarkable in these excellent chapters than the great names whose errors contribute to form the illustrative instances.

The last book of Mr. Mill's work is devoted to the Logic of the Moral Sciences : and there are many readers to whom it will be the most interesting of all, though it appears to us to present the appearance of self-imposed brevity and compression more than any of the parts pre- ceding. The author first shows that there is such a thing as a science of human nature ; next, which among the methods of investigation pre-

viously discussed in regard to the physical sciences are not applicable to it ; thirdly, which among those methods are applicable. On the first of

these points, he has to make good his ground both against M. Auguste Comte, who avowedly rejects all psychology (apart from physiology) as a mere chimera, and against those who maintain the freedom of the will, and who therefore deny (in theory at least) that those acts of mind called volitions are preceded by any regular and invariable antecedents. Of those methods which Mr. Mill deems unsatisfactory, and of those which he advocates, in regard to the science of human nature, we have no room here to give any farther account than to observe, that the diffi- culties embarrassing scientific study in this department, arising from the immense complexity of the agencies at work, are represented by him in a manner which we believe to be not less true than it is discouraging, and with which nothing short of the largest breadth of induction, and the happiest employment of the deductive process built upon it, can be expected to cope successfully.

There will be found in these volumes two excellencies which have never before been combined (to our knowledge) in any treatise of logic,—first, the largest range of philosophical survey, embracing all varieties of scientific method and study, and preserving all that is good in the techni- calities of the syllogism by marking out its due place in the full in- ferential process; - next, a close and constant grasp of realities, whereby we are made to feel that the speculations of the author have a distinct bearing upon the world as it stands, scientific as well as political. The last of these two merits they share to a great degree with the Elements of Logic by Archbishop Whately : in the first they seem to us to stand without a rival ; much more in the combination of the two. In the study of logic, nothing can be more disheartening than the wide gap between the principles of the science and the precepts of the art on the one hand, and actual practice on the other. The same man who assents to the principles and acknowledges the precepts, in general terms—not merely without difficulty, but even with a contemptuous derision against the teacher for having thought it necessary to inculcate such obvious truisms— will go down to the House of Commons, and make a speech, eminently successful and under universal cheering, wherein one or other of these logical precepts shall be infringed in innumerable instances : he will do this partly without consciousness, partly without scruple. Now Mr. Mill, while preserving with great strictness the philosophical purity of the prin- ciples, has always the art of presenting them as essential to the govern- ment of our practical judgment and conduct; not as technical restrictions imposed upon us only during the hours of formal disputation.

The difference between the second edition of the System of Logic and

the first is not very material. Mr. Mill has recast two of his chapters, one on the Calculation of Probabilities, another on the Grounds of Dis- belief. In the former edition, he had called in question the doctrine of Laplace respecting the foundations on which calculations of probability rested : he has now greatly modified—we might perhaps say retracted— this dissentient judgment.