“define" energy, but simply state what we seem compelled to understand by it-viz., "that which moves or tends to move the elementary atoms, or their aggregations into molecules and masses". Possibly, if I (as here) remove the comma which the printers slipped in between the word "aggregations" and the word "into," Dr. Cattell will remove the exclamation-point which he placed after the entire sentence.

Dr. Cattell also finds fault for its confusion with my theory of perception. Its "fallacy" consists, he thinks, in holding to "the assumption of a mind with a mysterious power of creating unity of consciousness out of sensation-atoms". This is not at all the way in which I should consent to have my view expressed. And here again any confusion which may possibly be pointed out in such a view is not my confusion. I am what Prof. James called, in the October No. of MIND, a 66 psychical stimulist," as regards the origin of space-perceptions. That is, I hold that the space-form which objects of sense certainly have is not the result of a mere summation (whether by addition or multiplication, to use Dr. Cattell's misleading figure; since what is multiplication but a form of addition ?) of non-spatial sensational elements. At the same time, I also hold that experimental analysis shows conclusively that many, if not all, of the sensational elements which enter into the presentations of sense do not originally possess the spatial quality which the results of their synthesis (the presentations of sense) certainly have. Therefore, I have argued, these spatial qualities are the results of the synthetic reaction of mind, according to its own laws of behaviour. Now Dr. Cattell may not accept or like this theory of perception; but I do not understand how he can rightly speak of it as necessarily fallacious or confused. As Prof. James shows in the article already referred to, such is virtually the view arrived at by far the greater majority of all investigators of sense-perception, whether they start from the philosophical or the experimental point of view. And I would undertake to show that Prof. James, with all the room he leaves to be filled by the mental acts of "identification," "summation," "imagination," rection," &c., is something of a "psychical stimulist " himself.

66 cor

Again, Dr. Cattell (very inconsiderately, I think) accuses me of "confusion amounting almost to contradiction" because, in one place (p. 391), I state the simple fact that objects of sense appear before the mind as out and spread-out, and in another place (p. 455) declare that this does not happen by way of copying off ready-made things which exist extra-mentally just as they are afterwards perceived. But all this amounts to saying that the objects of sense are mental constructions,—a statement which Dr. Cattell seems to approve. Since they are mental constructions, the qualities of being out' and 'spread-out' are not copied off from extra-mental things, but are imparted to the objects as the form in which the mind constructs them. Once more, I do not object to Dr. Cattell's holding any other view of perception which he thinks himself competent to defend; but I by no means confess to his charge of confusion and contradiction.

Dr. Cattell reiterates this charge of confusion against the chapter of my book on Feelings and Bodily Motions, although he is kind enough to say that the chapter was "evidently written with extensive knowledge of the German and English literature concerned with the subject". He gives to me, as well as to his other readers, scarcely any token, however, as to what this confusion consists in. All I can gather is that I am judged to have fallen again into my sad habit of getting confused, because I speak of "feeling with its colour-tone of pain or pleasure," and of an "involuntary act of will". As to the first point, I can only conjecture

that Dr. Cattell may be a follower of Herbart in his own theory of feeling. But certainly I have clearly, though briefly, pointed out the confusion of the whole subject in which the Herbartian theory involves us. As to the propriety of speaking of "an involuntary act of will" I have myself expressed doubt, but have consented to use the term, for want of a better, to indicate those "forced" acts of attention with which physiological psychology is so familiar.

Another instance of the facility with which Dr. Cattell discovers obscurities, and so feels impelled to dissent from its views, I find in his statement that my book holds the classification of tastes to be an easy matter. But, says Dr. Cattell, "no combination of sweet, sour, bitter and salt will give vanilla or chocolate, nor can the taste of lemon and sugar be analysed into sour + sweet". Now what the book says is this, that "most of the different kinds of tastes admit of being considered as compounds of a few simple sensations of this sense with each other and with sensations of smell, touch, common feeling and muscular sense” (p. 314). The ordinary classification I myself pronounce "loose," and I elsewhere (p. 354) hold that most of the complex tastes-strangely enough, instancing "chocolate" as one-cannot be wholly resolved into the simple kinds of gustatory sensations. Moreover, I also state that the modification of the acid of the lemon by the sugar is not a mere case of plus and minus, but that the explanation of the new sensation is in compound cerebral processes; the mixture takes place in the brain. Dr. Cattell furthermore thinks that I have through several chapters confused the doctrine of the Specific Energy of the Nerves with the fact that nerves connect special sense-organs and muscles with special braincentres. But again the confusion is not mine. The doctrine of the specific energy of the nerves I have stated, and touched upon in several places, but I believe always, with one exception, in such a way as to avoid all possibility of the confusion he finds. That one exception occurs in my summary of the conclusions respecting the localisation of cerebral function. There I say that all the results of investigation emphasise two great laws, one the law of Specific Energy and the other the law of Habit. It did not occur to me that any careful reader could suppose that in insisting upon the great and general principle of specific energy, as exemplified in the cerebral nervous mechanism, I should be thought of as confusing this use of the term with J. Müller's theory of "the specific energy of the nerves". It is perhaps worth notice in passing that Dr. Cattell thinks I am not justified in stating, and in italics: "Sensibility seems, then, to be the predominating function of the right hemisphere, as motion is of the left". He entirely overlooks the fact, however, that I am here giving a summary of Exner's conclusions.

Finally, Dr. Cattell more than intimates that, did he not refrain from discussing the more purely speculative part of my work, he should be compelled to point out other instances of confusion. I can only wish that, either by him or by some other critic, they might be brought to my notice. It might then appear whether the confusion is really mine or belongs to the false traditional opinions which are wont to be carried into the consideration of the relations between the body and the mind, and of the nature of the mind as made known through those relations. My critic is good enough to apologise, apparently, for some of my failures by saying that the preparation of a book on physiological psychology is "a task of the utmost difficulty". This is indeed true, I make no claim to have overcome all the difficulties, or to have dealt with them successfully. But I feel confident that I have at least avoided being myself confused on the points regarding which Dr. Cattell

complains of my confusion. I will close by saying that, in my judgment. the greatest difficulty which physiological psychology has had to encounter hitherto consists in the fact that it has been, with few exceptions, pursued by students lacking in psychological insight and broad philosophical training.

GEORGE TRUMBULL LADD.

LEIBNIZ AND HOBBES.

The recent discovery in the University Library at Halle of a large num ber of letters from the unwearied hand of Leibniz-surely the most epistolary of all great thinkers-does not thus far prove to have much philosophical importance. Dr. L. Stein, editor of the new Archiv für Gesch. der Phil., has in the first two numbers of that review given a careful account of all the autographic letters found, to the number of 101; and the utmost that can be said of them is that they help to deepen, if that were necessary, the impression of Leibniz as a man to whose breadth and variety of intellectual interests there was no bound, but who yet could pursue with the utmost tenacity special scientific objects of his own, as here the perfecting of his reckoning-machine, entrusted, from about 1700 (long after its first invention), to a Helmstädt mathematical professor, R. C. Wagner, his chief correspondent in the collec tion. There is promise, indeed, that in the next number of the Archiv some other of the Halle letters-but these only copies, though not before published-will be made to yield matter of philosophical interest, as touching the question of the scope and value of history of philosophy. Meanwhile it may be noted that the discovery at Halle is not the only addition that has just been made to our knowledge of Leibniz' amazing activity as a letter-writer. There has recently appeared vol. iii. of the division given to 'Correspondence' in the stately collection of Die philosophischen Schriften von G. W. Leibniz (Berlin, Weidmann), made since 1875 by C. J. Gerhardt, editor before of L.'s Mathematische Schriften. This volume was kept back while vols. iv.-vi. of Works' were being issued from 1880. Apparently, though the editor says nothing, some kind of supplement must still be in view, outside of the original scheme; various things remaining unaccounted for within either division, as, for example, the well-known correspondence with Samuel Clarke. With all his merits and his unique claims to the gratitude of Leibniz. students, Gerhardt, it must be said, has not in all respects chosen the happiest way of presenting the fruits of his research; in parti cular, he might have been more forward with the reasons for some of his action in the past, and now he might have been less silent as to his actual intentions. There can, however, be no question as to the philo sophical interest and value of the new, and hardly less of the corrected, matter which, in all his volumes (of Works' as well as Correspondence'), he has, with extraordinary labour, been able to bring forth from the recesses of the Royal Library at Hanover. In his latest volume-to go no farther back-at least one important interchange of letters (with Jacquelot, pp. 442-82) is made known for the first time; while other correspondences, more or less imperfectly printed before (some in merest fragment), are now set out with all desirable fulness and care. Among these are three: (1) with Thomas Burnett of Kemnay, a Scottish friend of Locke's; (2) with Cudworth's daughter, Lady Masham, the comforter of Locke's declining years; (3) with Pierre Coste, the French ranslator (in England) of Locke's Essay, which throw so much new light on the relations of the German to the English philosopher that another

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occasion may be sought for giving some detailed account of them in these pages. At present there is something to tell, from another source, of the relation in which Leibniz stood to an earlier English thinker-a relation that had not before been half carefully enough studied, and which, indeed, has been wholly overlooked by most expositors of Leibniz, including Mr. Theodore Merz, who, in his excellent contribution to Blackwood's Philosophical Classics" (see MIND ix. 439), first set the great German fairly before English readers.

It is that earnest student of Hobbes, Dr. Ferdinand Tönnies, who, in a recent article in the Philosophische Monatshefte (xxiii. 557-73), has placed in a light as striking as it is new the intellectual debt of Leibniz to Hobbes. Leibniz, it may be well to remind the reader, was contemporary with Hobbes in the last third (1646-79) of the nonagenarian's life. It has long been known that the ardent young thinker, impressed at an early age by Hobbes among other of the new 'mechanical' philosophers, sought to enter into closer relations with him by a complimentary and interrogatory letter, written from Mainz in the year 1670. The letter was first printed, from a copy of it taken by Oldenburg through whom it was sent to Hobbes, in Guhrauer's biography of Leibniz, whence it passed without change into Gerhardt's vol. i., pp. 82-5 (having, by the way, its gist somewhat too loosely represented at p. 48). Now Dr. Tönnies has had the good fortune to find, in the same volume (4294) of Sl. MSS. in the British Museum with Oldenburg's copy (nearly correct in itself, but not always carefully followed by Guhrauer), a document that has all the appearance of being Leibniz' original letter. gives the first quite accurate transcript, appending to it a series of remarkably instructive "elucidations".

Of this he

For the understanding of the development of Leibniz' thought—a subject of peculiar interest and difficulty-Dr. Tönnies's few pages make more really effective use than has yet been made of the rich material now rendered accessible by Gerhardt's diligence. It has recently been used, not without effect, by Dr. David Selver for two elaborate articles in the Philosophische Studien (iii. 217-63, 420-51, "Der Entwickelungsgang der Leibniz'schen Monadenlehre bis 1695"); but this careful writer, who ranges also over a wider field to good purpose, has overlooked, like others before him, the facts now discerned, with characteristic penetration, by Dr. Tönnies. When read in connexion with the various utterances in letters or other writings from 1663 which Dr. Tönnies has been the first to marshal, the letter of 1670 leaves it hardly doubtful that, up to this date at least, Leibniz was more deeply affected by Hobbes than by any other of the leading spirits of the new time. If as late as 1669 he could, in a letter to J. Thomasius, express a preference for the doctrine of Aristotle's Physica over that of Descartes' Meditationes, he cannot have been very familiar with this treatise, so purely philosophical in character as it is, and it may well be doubted, with Dr. Tönnies, whether he can by that time have read at all Descartes' chief work, the Principia Philosophia, which does contain a physical, as well as metaphysical, doctrine. To be sure, the letter of 1670 itself includes a very high-flown reference to the French philosopher, but there is every reason, notwithstanding, to believe that Leibniz' serious occupation with Descartes' philosophy followed upon the years from 1672 in which he gave himself with such ardour and brilliant success to the study of mathematics; as, probably, it then was from the sense of having so swiftly surpassed Descartes in mathematical discovery that he always continued more eager to accentuate their differences than their agreements in philosophy. On the other hand, we find him, by the year 1670,

not only conversant with Hobbes's thought at all its stages, whether of principle or application, but evidently concerned to get some accommodation of it to those practical interests of religion which were uppermost with him all through life. The time was near when he could not retain the faith he may have had even in the mathematical pretensions of the De Corpore, but, as Dr. Tönnies shows, other ideas, logical, metaphysical and even physical, plainly to be traced to that work, remained always operant with him. The most signal, undoubtedly, is that reference by Hobbes, in De Corpore, c. 25, § 5, to the possibility of regarding all bodies whatever as endued with sense in so far forth as reactive, though he himself proceeds to urge that it should be limited to living creatures, which do not simply react but have special organs for the retaining of impressed motion or-as he interprets this-have memory. Leibniz clearly has the passage in view when, in the letter of 1670, he goes so far beyond Hobbes (in the direction of Descartes) as to doubt whether sense can be more properly ascribed to brutes than "pain to boiling water". But already in the following year, as Dr. Tönnies points out, he is found harking back, in the tract Theoria Motus Abstracti, to a position which is essentially the same as Hobbes's, though he gives it an affirmative expression, peculiar to himself, which is of the utmost significance in view of the Monadism of later years. Two sentences may here be quoted: "Nullus conatus sine motu durat ultra momentum, præterquam in mentibus. . . . Omne enim corpus est mens momentanea, sed carens recordatione." It did not escape Leibniz' contemporaries whence he had got his inspiration; for Dr. Tönnies is able to cite the words of mournful reproach with which a forgotten G. Raphson, in controversy with Leibniz on the point, brings forward the very passage from Hobbes. Dr. Tönnies himself, in view of it, and in view of the farther development of Leibniz' thought that may now be referred definitely to 1678 (since publication by Gerhardt of his marginal notes written on Spinoza's Ethica in that year), does not hesitate to describe his metaphysical doctrine as, in strictness," a Hobbism that had taken up Spinozism into it," or, again, to say: for Leibniz "Hobbism is the true physics; Spinozism, the true psychology". However this may be,--and certainly account has to be taken of a number of still later stages of development, at least in expression, before Leibniz, close upon the end of the century, had final possession of his doctrine, enough should have been said to show that Dr. Tönnies has done a real service in drawing attention to an aspect of it that in recent times has not been at all regarded.

The letter to Hobbes (then 82) remained unanswered for all its compliments, which should not have been ungrateful to the old man amid so much hostile clamour as attended his closing years. Dr. Tönnies is doubt. less right in ascribing to disappointment the petulant terms in which Leibniz, writing to Thomasius some months later in the same year, speaks, on Oldenburg's authority, of Hobbes as passing into second childhood. It must have been a transient shade of feeling, for some time later-apparently in 1672, from Paris-he began to address another letter of appreciative criticism to the aged thinker (given by Guhrauer and Gerhardt from the unfinished draft at Hanover). There is no evidence of their having met when Leibniz came over for some weeks to London, early in 1673; most probably, Hobbes was then in Derbyshire. EDITOR.

66 A SECOND LAURA BRIDGMAN."

The blind deaf-mute Laura Bridgman, now at the age of 58, has recently completed, amid due festal celebrations, the 50th year of her residence