last number, I beg to say that Dr. Ingleby has betrayed' me into no error. If I have fallen into error, it is with my eyes open, and after satisfying myself by study of Kant, that to speak of Space and Time, whether as forms of understanding, or as forms of thought, is an unauthorised and misleading mode of expression. Space and Time are forms of sensitivity or intuition. The categories of Kant (so essentially in this point differing from those of Aristotle) do not contain Space and Time among them, and are properly called forms of understanding or thought.

To the existence of thought the operation of the understanding is a necessary preliminary.

Sensibility and intuition are antecedent to any such operation. Can Mr. Lewes point to any passage in Kant where Space and Time are designated forms of thought? I shall indeed be surprised if he can do so-as much surprised as if Mr. Todhunter or Mr. Routh, in their Mechanical Treatises, were to treat energy and force as convertible terms. To such a misuse of the word energy it would be little to the point to urge that force without energy is a mere potential tendency. It is just as little to the point in the matter at issue, for Mr. Lewes to inform the readers of Nature that intuition without thought is mere sensuous impression.

Dr. Ingleby has rendered, in my opinion, a very great service to the English reading public, by drawing attention to so serious and prevalent an error as that of confounding the categories (the proper forms of thought as thought) with Space and Time, the forms of intuition, the sentinels, so to say, who keep watch and ward outside the gates of the Understanding.

Athenaeum Club, Jan. 15.

J. J. SYLVESTER.

ALTHOUGH I do not feel myself called upon to modify in the least what was said in my former letter on this subject, the three letters which appear to-day in answer to it are too important to be left unnoticed.

The case is briefly this: In the History of Philosophy' I had

to expound Kant's doctrine, and to criticise it, not only in itself, but in reference to the great question of the origin of knowledge. In the pages of exposition I uniformly speak of Space and Time as forms of Intuition; no language can be plainer. I also mark the distinction between Sensibility and Understanding, as that of Intuition and Thought. After enumerating the Categories, I add, In those Categories Kant finds the pure forms of the Understanding. They render Thought possible.'

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But when, ceasing to expound the system, I had to criticise it, and especially to consider it in reference to the great question; there was no longer any need to adhere to a mode of expression which would have been obscure and misleading. I therefore uniformly class Space and Time among the forms of Thought, connecting them with the doctrine of Necessary Truths and Fundamental Ideas, which, according to the à priori school, are furnished ready-made—brought by the Mind as its native dowry, not evolved in it through Experience.

Now the question is, Have I put language into Kant's mouth which he would disclaim, or is such language misleading? That Kant would have said the language was not what he had employed, I freely admit; but that he would have disclaimed it as misrepresenting his meaning, I deny. I was not bound to follow his language when the task of exposition was at an end; but only bound not to translate his opinions into language which would distort them.

In classing Space and Time among the Forms of Thought, I classed them beside the Categories of the Understanding and the Ideas of Reason, i.e. the purely intellectual conditions existing à priori in the Mind. The Mind is said by Kant to be endowed with three faculties-Sensibility, Understanding, and Reason. The activity of the Mind is threefold-Intuitive Thought, Conceptive or Discursive Thought, and Regulative Thought. There could not be an equivoque in my using the word Thought in its ordinary philosophical acceptation as expressive of all mental activity whatever, exclusive of mere sensation; although Kant assigns a more restricted meaning in his technical use of the word, i.e. what we call Logic. And that Kant meant nothing

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opposed to the ordinary interpretation is obvious. It is obvious because, as I said in my former letter, Intuition without Thought is mere sensuous impression. Mr. Sylvester demurs to this, so I will show it in a single citation:-'In the transcendental Aesthetic,' says Kant, we will first isolate Sensibility by separating from it all that the Understanding through its concepts thinks therewith, so that nothing but empirical Intuition remains. Secondly, we will lop off from this empirical Intuition everything relating to sensation (Empfindung); so that thereby nothing will remain but pure Intuition and the mere form of phenomena, which is the one thing that Sensibility can furnish à priori. By this investigation it will appear that there are two pure forms of sensuous Intuition which are à priori principles of Cognition. (Kritik,' § 1, ed. Hartenstein, p. 61.)

Mr. Sylvester correctly says, that Intuition and Thought are not convertible terms. But he is incorrect in assuming that they differ as potential and actual; they differ as species and genus; therefore, whatever is a form of Intuition, though not a form of Logic, must be a form of Thought; unless intuitive Thought be denied altogether. How little Kant denied it is evident in every section of his work. In asserting that Space and Time as Intuitions belong to the subjective constitution of the Mind-subjectiven Beschaffenheit unseres Gemüths (p. 62)— he expresses this; but it is unequivocally expressed in the following definition :-'A perception, when it refers solely to the subject, as a modification of its states, is sensation, an objective perception is cognition: this is either Intuition or Concept, "intuitus vel conceptus." ('Kritik,' p. 294.) Is not thought implied in cognition? Again :-'The proposition "I think" is an undetermined empirical Intuition, i.e. Perception consequently, it proves that Sensation, which belongs to Sensibility, must lie at the basis of this proposition. . . . I do not mean thereby that the "I" in the "I think" is an empirical representation (Vorstellung), on the contrary, it is purely intellectual, because it belongs to thought in general. But without some empirical representation which would give Thought its material there could be no such act of Thought as the "I think" (p. 324, note).

'Man is always thinking,' says Hegel, 'even when he has nothing but intuitions'-denkend ist der Mensch immer auch wenn er nur anschaut. (Encyclop. § 24.)

If, because Kant has a restricted use of the term Thought, all who venture on the more ordinary use are said to misrepresent his philosophical meaning, I must call upon those who criticise this laxity to refrain henceforth from speaking of Reason as Thought, since Kant no less excluded Reason from the province of the Understanding. If the only forms of thought, in Kant's sense, are the Categories,' this sweeps away Reason on the one side, as it sweeps away Sensibility on the other; and Ideas are not more correctly named Thoughts than Intuitions are. Kant, it is true, speaks of the concepts of Reason, and defines an Idea to be a 'Vernunftbegriff' (page 294); but Kant, equally and in a hundred places, speaks of the 'concept of Space' (Begriff des Raumes). The truth is, as already intimated, that in spite of his technical restriction of Thought to the formation of concepts, he recognised intuitive and regulative Thought no less than discursive Thought; nor would his system have had any coherence without such a recognition. Why does he call his work the 'Critik of Pure Reason,' unless he intended to display the common intellectual ground of Sensibility, Understanding, and Reason? and does not the word Thought, in ordinary philosophical language mean this activity of the Intellect? When, by Sir W. Hamilton, Dr. Whewell, Mr. Spencer, and myself, the phrase Forms of Thought is used, does not every reader understand it as meaning Forms of intellectual activity?

In conclusion, I affirm that in the ordinary acceptation of the term Thought-the activity of the Mind-Space and Time as forms of Intuition are forms of Thought, conditions of mental action; and to suppose that because Kant's language is different, his meaning is misrepresented by classing forms of Intuition among the forms of Thought is to misunderstand Kant's doctrine and its purpose. GEORGE HENRY LEWES.

January 22.

Dr. INGLEBY, I should think, is quite entitled to say not only that Kant might, but that he would, have disclaimed the phrase Form of Thought as applied to Space or Time taken simply. The remark of Mr. Lewes, that 'intuition without thought is mere sensuous impression,'—or, as it might have been put, that phenomena of sense (constituted such in the forms of Space and Time) must further be thought under Categories of Understanding, before they can be said to be known or to become intellectual experience—cannot be a sufficient reason for making a Form of Thought proper out of a Form of Intuition.

There is, nevertheless (and Mr. Lewes does not fail to suggest it), a sense in which, when taken along with the Categories of the Understanding, and with or without the Ideas of the Reason, the Forms of Intuition may be spoken of as Forms of Thought: Thought being understood, with the same extension that Kant himself gives to Reason in the title (not the body) of his work, as equivalent to faculty of Knowledge in general. It is in this sense that Kant calls all the forms alike, à priori principles of Knowledge; and the ambiguity of the word Thought is so well recognised that the English writers arraigned by Prof. Sylvester take no great liberty, when for their purpose, which commonly is the discussion of the general question as to the origin of Knowledge, they talk generally of Kant's 'Forms of Thought.' If, indeed, any of them ever speaks of Space as a 'form of the Understanding,' which was part of the original charge, the case is very different; Kant being so careful with his Verstand. But Mr. Lewes, at least, would never be caught speaking thus, even though his main reason for merging Intuition in Thought might seem to justify this also. G. CROOM ROBERTSON.

University College, January 22.

You will perhaps permit me to make a remark on a controversy at present going on in your columns. There has seldom, I believe, been a grosser or more misleading perversion of the Critical Philosophy than ascribing to Kant the view that Space and Time are in any meaning of the terms 'forms of thought.'