(In correspondence with this, recognising that the same method has to be adopted in all inquiry, whether we deal with the body or the mind, the following may be quoted from Hume's Treatise on Human Nature. "'Tis evident that all the sciences have a relation, greater or less, to human nature; and that, however wide any of them may seem to run from it, they still return back by one passage or another. Even _Mathematics_, _Natural Philosophy_, and _Natural Religion_ are in some measure dependent on the science of MAN, since they lie under the cognisance of men, and are judged of by their powers and qualities.) "The analogy between individual organisms and the social organisms is one that has in all ages forced itself on the attention of the observant.... While it is becoming clear that there are no such special parallelisms between the constituent parts of a man and those of a nation, as have been thought to exist, it is also becoming clear that the general principles of development and structure displayed in all organised bodies are displayed in societies also. The fundamental characteristic both of societies and of living creatures is, that they consist of mutually dependent parts; and it would seem that this involves a community of various other characteristics.... Meanwhile, if any such correspondence exists, it is clear that Biology and Sociology will more or less interpret each other. "One of the positions we have endeavoured to establish is, that in animals the process of development is carried on, not by differentiations only, but by subordinate integrations. Now in the social organism we may see the same duality of process; and further, it is to be observed that the integrations are of the same three kinds. Thus we have integrations that arise from the simple growth of adjacent parts that perform like functions; as, for instance, the coalescence of Manchester with its calico-weaving suburbs. We have other integrations that arise when, out of several places producing a particular commodity, one monopolises more and more of the business, and leaves the rest to dwindle; as witness the growth of the Yorkshire cloth districts at the expense of those in the west of England.... And we have yet those other integrations that result from the actual approximation of the similarly-occupied parts, whence results such facts as the concentration of publishers in Paternoster Row, of lawyers in the Temple and neighbourhood, of corn merchants about Mark Lane, of civil engineers in Great George Street, of bankers in the centre of the city" (Essays, vol. iii, 1878 edition; Transcendental Physiology, pp. 414-416). But, divested of technicalities, and summarized in words to be "understanded of the people," the following quotation from the Essay on Progress: Its Law and Cause, gives the gist of the Synthetic Philosophy: