and to them, a symbol of that group. It is a synthesis of experiences, some of which can analytically be expressed; others transcend expression, and are mysterious. If he attempts to pass beyond the sensible qualities capable of analytical expression, and seeks to know what water is over and above its liquidity, transparency, specific gravity, temperature, etc., two courses are open to him: first, he may resolve the liquid into its constituent gases, and submit these to sensible experiences, which assure him that they are the constituents plus a certain quantity of molecular agitation; secondly, not having the means of further reduction, he may call in the aid of hypothesis, and invent a possible group of conditions which would produce the phenomena if present; and this double inference of their presence and their influence he must try to verify by the reduction to Sense or Intuition.

THE SUBSTRATUM.

8. Matter is thus known as real, by synthesis of sensibles; as ideal, by analysis; and it is hypothetical, as postulated by analysis and fiction. What is given in Feeling can only be explained by analysis and a subsequent synthesis of the ideas thus gained. The chemist who explains the composition of water has so far enlarged our knowledge of what the group of sensibles named water was and will be under other sensible relations; he has not altered our knowledge of what the water is under present relations his analysis cannot affect our synthesis of experience. The common error of supposing that a thing really is something different from what it appears may perhaps cause some reader to urge the following objection: "You imagined that it was the water which had the qualities you assigned to it; now the chemist proves that water itself does not exist, but only oxygen and hydrogen combined in certain proportions, and these have not the

qualities of water, but their own different qualities. Nay more: these very gases are only hypothetical elements; they may some day be shown to be compounds. So that wherever Analysis penetrates, the Matter, supposed to be known, disappears, giving place to an unknown substratum."

9. Our answer will be, that what is known cannot be reversed by any extension of our knowledge, or by any substitution of one group of sensibles for another. No fact can be explained away; it can only have its genesis revealed in an exhibition of its antecedents. Analysis unfolds, and renders conspicuous, some of the factors already inconspicuously present in the synthesis of Perception or Conception, and thus enables us to explain an experience by connecting it ideally with other experiences. When analysis succeeds in reducing a complex fact to its component factors, sensible or extra-sensible, there is indeed an enlargement of knowledge. When the factors are hypothetical there is no enlargement, only a more or less serviceable guess. Applying these principles to the hypothetical substratum invented as an unknown support of real qualities, we see at once that it is not only an hypothesis, but one which is incapable of verification. It is the personification of a logical artifice. We logically separate the subject from its predicates, and then commit the mistake of supposing this logical separation to be real. We logically separate the abstract symbol of the group of qualities from the concrete qualities severally considered, and then suppose the group to be a different Real from the particulars grouped. But, it may be said, there is an element in the compound quality which is something over and above what is felt, the purely objective substance, that which is called the Possibility of sensations,

that which was before it acted upon Sense to become sensible object, and will be when our Sense is in no relation

to it. Perhaps so. This may be accepted as a postulate ; but my argument is, that this "something more" is simply the same objective factor in another relation than that in which it exists as a sensible. The substratum is a postulate of possible relations, and the initial error of metaphysicians on this point has been to confound a postulate with a principle. The law of inverse squares, for example, is a principle, not a postulate, and from it Kepler's laws are seen to flow in necessary sequence; but what facts or laws of sensible quality can be said to flow from the postulate of a substratum? The law of attraction enters into and manifests itself in the movements of the heavenly bodies;* the one is only a presentation of the other under different points of view. But the imaginary substratum does not enter into and manifest itself in sensible qualities; on the contrary; it holds itself aloof, is distinguished from them in esse, and is altogether incapable of coming within the range of sense.†

10. This has been stated very perspicuously by Descartes, who, after noticing the various changes which a morsel of wax undergoes on the application of heat, losing one by one its original qualities, yet always remaining the same morsel of wax, remarks that this which remains is only perceptible by the mind, it is not a vision, nor a touch, nor was it ever such, although it seemed to be so, but simply "une inspection de l'esprit." If, therefore, the substance is an ideal, not a sensible exist

* In what sense this is to be understood will be explained presently, § 38.

+ "Matematicamente se si cerca l'effetto di una palla lanciata contro uno ostacolo, si parte dai dati della forma, del volume, della densità, della velocità, della direzione di essa, e non della sua essenza materiale. E il calcolo astratto è applicabile con infallible precisione a tutte le palle, in cui si incontrino i medesimi estremi di fatto, qualunque sia la sostanza onde constano." -ARDIGÒ, La Psicologia Come Scienza Positiva, 1870, p. 71.

+ DESCARTES, Meditations, II.

ence, we have to trace its ideal genesis; that has been indicated in the preceding paragraph.

11. We logically separate Substance from its qualities, and this is a perfectly legitimate artifice when it represents the distinction between Subject and Predicates; or, to speak more precisely, the general group of qualities from any one special item of that group. When we say iron is solid or fusible, we mean that solidity or fusibility may be observed among the other properties observed in the group named "iron." The substance "iron" here stands for the unspecified properties; the specified properties solidity and fusibility have already been observed (or inferred) along with the other properties, and constitute essential elements of the group "iron." To carry this separation further, and to suppose that there is a Substance which is not these properties, is equivalent to supposing there is a Number which is not the sum of its units.

12. The foregoing exhibition of the three conceptions which are expressed under the one symbol Matter, was necessary to a clear statement of the problem. Think of the confusion which would arise in scientific discussions if the debaters were not alive to the totally different meanings attached to the term Induction, which expresses. a logical process, an electro-static process, and an electromagnetic process; logical induction is not electro-static induction, nor anything metaphorically like it; nor is knowable Matter the same as Substratum, nor anything resembling it. There is a resemblance between sensible and extra-sensible Matter, but there are also broad distinctions; and when we are treating of extra-sensible atoms, we are treating, not of the Matter positively known, but of the Matter speculatively known, not of the Reality which is perceived, but of that which is conceived.

CHAPTER II.

APPLICATION OF OUR METHOD.

13. WE have affixed definite significations to our terms, and may now proceed to indicate how rational solutions of all rational questions respecting Matter may be reached through the Method sketched in the Introduction to this work. I say rational questions, and mean thereby to exclude all that are metempirical, since, according to the views here adopted, Philosophy is the product of reflection systematizing the data of Experience, sensible and extrasensible, positive and speculative, but excluding whatever is supra-sensible. Founded upon Observation, and the classification of observations, there are speculative constructions of two orders: one in which Inference extends Observation, always keeping on its lines; the other in which Inference departs from the lines of Observation, and strikes into different paths. The one expands the mind with germinating seeds of Discovery, the other puffs it up with the wind of Debate.

THE RANGE OF EXPERIENCE.

14. And here a word must be said on the important question of Experience, which is of such vital importance that the reader must pardon my frequent recurrence to it. Misapprehension of what that word denotes and connotes. must prevent any acceptance of the empirical philosophy; and the word has been so vaguely used, generally with such unwarrantable restriction to mere sensation, that the