button to fasten his coat, a garter to keep his stocking up. Indeed, this is the case everywhere. My hand compressing a full sponge carries the constitutive particles of the latter nearer each other, and the mobile water is forced to quit. Surely the force here is a very sensible power. But the case is not different when a pricked bladder collapsing drives the air out by the force of its elasticity. That latter force, though inanimate, is quite as the former; and the two are perfectly susceptible of the most accurate, proportionate admeasurement. Certainly the hand is not the sponge, and the bladder is not the air: each is itself, and very different from the other. Nevertheless, in regard to the action which has taken place between them, it is a concrete, and holds of both. Brown would have us ignore all between. He would have us see an abstract or independent individual A put down, and just on the instant, for no known reason, an abstract or independent individual B start up! Such relation really seems so on the part of a struck key and a heard note on the piano. The key is A, the note is B; and they seem abstractly beside each other. But, in point of fact, even they are not the abstract side by side, invariably so found, which Brown would have us hold to be the sole state of the case in the cause and in the effect. Open your piano, and you will see the concrete mechanism between the copula, the medium, of the struck and vibrating wire. The ultimate specific copula between the air-wave and the sound in the ear-medium between matter and mind--we do not know; but we do know that there are steps to it. What are all these ossicula, and cochleæ, and scale, etc. ?What but machinery adapted for the purpose? Put the end of a stick in the fire, and it is burned black. The stick simply becomes black; it feels no power that makes it black. The state of the

case would, in all essentials, remain pretty well the same, were there substituted for the stick the finger of a corpse. Were there substituted, however, a living finger, the force, the power of the fire would be felt; for in that case there are nerves. A piece of white wood. blackens under the clear drop that shall be one of vitriol. The wood is blackened under the drop for the same reason that the stick was blackened in the fire. In either case the withdrawal of the water (call it simply HO) left (C) the carbon in sight-black. The wood no more felt the power of the acid than the stick felt the power of the fire; but a living finger would be in case to feel both. In all cases of causality, there is the mediation of a tertium quid: there is the process, action, motion of a middle term between the extremes. And it is not by any means an objection in place to say this middle term is not always known. A great many middle terms are hidden from the savage; but for us, members of civilisation, science is only there to teach us middle terms. In fact, just in a general regard, and every way, civilisation is nothing but-knowledge of middle terms. Were the extremes in causality only, as Brown would have them, strictly collateral, nakedly collateral, an abstract AB (but invariable), then science there would have been none, civilisation there would have been none. Humanity itself is simply-necessity of rationale: it is alone the middle term that is the entire secret of the universe.

Reid, too, was on the whole unhappy in seeing power, that is, middle terms, only in the case of animate causation; for, at least so far as most people are concerned, it is precisely in animate causation that, not unfrequently, a middle term seems the want seems singly that which is unable to be found. "How it is that anything so remarkable as a state of consciousness comes about

as the result of irritating nervous tissue, is just as unaccountable as the appearance of the Djin when Aladdin rubbed his lamp in the story." This is what Mr. Huxley says; so that he for one, at all events, finds himself at a loss for a middle term when the physical and the metaphysical meet. Whatever be the structure of the ear, it is, in ultimate instance, still a vibration on the physical side that suddenly starts up a sound on the metaphysical side. And in that situation, and as so described, we may best understand what Brown's decision comes to the decision of simple invariableness. What is meant by an abstract A B is perfectly visible there. Vibration is the A, and sound is the B. The vibration is abstract, isolated, on its side; and the sound is abstract, isolated, on the other side. The relation itself is abstract. The terms of it, the sides of it, only touch: there is no concrete connection between them. Nor is the case easier, or in any way different, where any other meeting place of physiology on the one hand, and psychology on the other, are concerned. Alum and astringency for taste, a rose-leaf and fragrance for smell, wool and warmth for touch: there, too, in each case we have only abstract sides; the middle term that is concretely to bridge them, we cannot see in any one of them. With sight the difficulty is only greater, and perhaps only all the more that on the one side, the physical one, the intermediation of middle terms is so abundant and curious. To obtain that image on the retina the contrivances are as nice as numerous, as minute as vast; but the image physiological and the image psychological differ still by the whole diameter of being. Image and image are but an abstract A B. So it will always be when internality and externality are brought into relation. There, too, there is a direct side by side where the line between has neither breadth nor

thickness. Nevertheless that dimensionless line is but an immeasurable gulf. And in this we may seem to have raised up an insuperable barrier to our own selves. We say between the extremes of cause and effect, there is always a middle term of embrace; yet here, where psychology and physiology, inner and outer, are concerned, we seem to say, in exact contradiction of our own selves, that middle term there is none. And we admit that the state of the case must not only seem, but actually be so-unless we can find the one ultimate middle term that explains all, and is the single principle of the universe! But that is an interest for a special elsewhere. We can say now this, however, that no scalpel to ear or eye or brain will do more than simply complicate the physical side: it will never reach the bridge—it will only lengthen the way to it.

All that we wish now is that it should be seen what Brown's invariableness amounts to. It is no solution of the problem: it is, in fact and in truth, the very crux of the problem itself. Why is there the invariableness— say of nerve (lamp) here, and of consciousness (Djin) there? The invariableness it is that is the special difficulty. How do you account for it? What is your explanation of it? Were we to deal with you in your own way, indeed, we should ask, How do you even know the invariableness? You can, and you do, only refer this invariableness to experience; but no experience is exhaustive-no mere experience is adequate to a must. Make experiences as numerous as you may, they are still but experiences-facts found simply as facts, not combinations reasoned into necessities of insight. The separate facts that have been, if they are no more than facts, bring with them no certainty that they will be. Even an always in the past, if no more than such always, is no guarantee for an always in the future. That stands to reason; and

it stands equally to reason, that a thousand respective measurements will never counterpoise or equate the single geometrical proof (say, e.g., of Euclid, I. 32, or I. 47).

So, just in every way, Brown's invariableness in explanation of causality is a proposition untenable, is a proposition crude. The darkness of an eclipse, or the lifting up in the balance of the pound weight by the two pound weight, are not matters of mere invariableness, but of insight as well. These glasses are the cause of the clearness of that print; but the glass is not just abstract on the one side, and the clearness equally abstract on the other. Even a savage would give a bewitched inside of power to the glass, which a Newton would convert into a transparent concrete of reason-with no barrier but what, as said, is apparent, always at last between psychology and physiology, physics and metaphysics, matter and mind.

It is not so certain, however, that such explanations of concretes by abstractions, as that, in the case of Brown, of causality by invariableness, may not have bad results elsewhere. Political Economy, for example, is a science absolutely true in its great generalisations. But these generalisations are not true if only left abstract. They must, on the contrary, be seen into and understood. Abstractions must be deepened and vitalised into concretions. Demand and supply, for instance, will never come together, if they are separated by customs and prohibitions, and ships of war in support. Supply, when it is a human being that sees a profit to itself in Demand, will always incline to realise that profit-unless precluded and prevented. So it will cultivate the very worst lands in existence, provided only that they will yield a profit; and that is but a part of the fact that the law of rent is no abstraction, but a fact—a concrete natural fact. Good lands, and well-placed lands, must yield more than