words differentiation and integration? Spencer appears to think so. Of course he did exceptionally fine work in elucidating the modes of differentiation and integration within certain relational fields—though he sometimes uses the latter word for mere shrinkage in size.[52] But what one asks, and asks of him in vain, is just how, within a connected scheme, the several relational fields in the domain of nature are themselves related, and how they were themselves differentiated. How, for instance, did the specific relationships exhibited in the fabric of crystals arise out of the primitive fire-mist relations? At some stage of evolution this specific form of relatedness came into being, whereas before that stage was reached it was not in being. No doubt we may say that the properties of the pre-existing molecules were such that these molecules could in due course become thus related, and enter into the latticed architecture of the crystal. They already possessed the potentiality of so doing. And if we have resort to potentialities, all subsequently developed types and modes of relatedness were potentially in existence ab initio—they were, as Tyndall said, 'once latent in a fiery cloud.' But it is difficult to see how the specific modes of relatedness which obtain within the crystal, can be said to exist prior to the existence of the crystal within which they so obtain.

Preserving the spirit of Spencer's teaching we must regard all modes of relatedness which are disclosed by scientific research as part and parcel of the constitution of nature, from whatever Source, knowable or unknowable, that constitution be derived. Of these modes there are many; indeed, if we deal with all concrete cases, their number is legion. For purposes of illustration, however, we may reduce them, rather drastically, to three main types. There are relations of the physico-chemical type,[53] which we may provisionally follow Spencer in regarding as ubiquitous; there are those of the vital type, which are restricted to living organisms; there are those of the cognitive type, which seem to be much more narrowly restricted. How we deal with these is of crucial importance. Denoting them by the letters A, B, C we find that there are progressively ascending modes of relatedness within any given type. There is evolution within each type. Within the physico-chemical type A, for example, atoms, molecules, and synthetic groups of molecules follow in logical order of evolution. Now the successive products, in which this physico-chemical type of relatedness obtains, have certain new and distinctive properties which are not merely the algebraic sum of the properties of the component things prior to synthesis. We may speak of them as constitutive of the products in a higher stage of relatedness, thus distinguishing constitutive from additive properties.[54] Similarly when B, the vital relations, are evolved, the living products, in which these specific relations obtain, have new constitutive properties, on the importance of which vitalists are right in insisting, though I emphatically dissent from some of the conclusions they draw from their presence. For if, beyond the physico-chemical, a special agency be invoked to account for the presence of new constitutive properties, then, in the name of logical consistency, let us invoke special agencies to account for the constitutive properties within the physico-chemical—for radio-active properties for example. If a Source of phenomena be postulated, why not postulate One Source of all phenomena from the very meanest to the very highest? There remains the case of C—the synthetic whole in which cognitive relatedness obtains. This is unquestionably more difficult of scientific interpretation. But I believe that like statements may be made in this case also. What we have, I conceive, is just a new and higher type of relatedness with specific characters of its own. But of this more in the sequel.

It must be remembered that A, B, C stand for relationships and that the related things are progressively more complex within more complex relational wholes. Relationships are every whit as real as are the terms they hold in their grasp. I do not say more real; but I say emphatically as real. And if this be so, then they ought somehow to be introduced into our formulae, instead of being taken for granted. We give H₂O as the formula for a molecule of water. But that molecule is something very much more than two atoms of hydrogen + one atom of oxygen. The absolutely distinctive feature of the molecule is the specific relatedness of these atoms. This constitutive mode of relatedness is, however, just taken for granted. And it is scarcely matter for surprise that, when we find not less specific modes of vital relatedness in the living organism, they are too apt to be just ignored!

Revert now to the empirical outcome of scientific research, for as such I regard it, that new constitutive properties emerge when new modes and types of relatedness occur, and when new products are successively formed in evolutional synthesis. This, it will be said, involves the acceptance of what is now commonly called creative evolution. I am far from denying that, in the universe of discourse where Source is under consideration, the adjective is justifiable. But, in the universe of discourse of science, I regard it as inappropriate. What we have is just plain evolution; and we must simply accept the truth—if, as I conceive, it be a truth—that in all true evolution there is more in the conclusion than is given in the premises; which is only a logical way of saying that there is more in the world to-day than there was in the primitive fire-mist. Not more 'matter and energy', but more varied relationships and new properties, quite unpredictable from what one may perhaps speak of as the fire-mist's point of view. This is no new doctrine, though it has received of late a new emphasis. Mill, dealing with causation,[55] speaks of a 'radical and important distinction'. There are, he says in substance, some cases in which the joint effect of the several causes is the algebraical sum of their separate effects. He speaks of this as the 'composition of causes', and illustrates it from the 'composition of forces' in dynamics. 'But in the other description of cases', he says, 'the agencies which are brought together cease entirely, and a totally different set of phenomena arise.' In these cases 'a concurrence of causes takes place which calls into action new laws bearing no analogy to any that we can trace in the separate operation of the causes'. They might, he suggests, be termed 'heteropathic laws'. G. H. Lewes, too,[56] in his Problems of Life and Mind, drew the distinction between properties which are resultant and those which are emergent. These suggestions were open to Spencer's consideration long before the last edition of First Principles appeared. They were, however, too foreign to the