Note 7 — SUPPLEMENTARY ESSAYS. (continued 2)

Viz., the constant association within experience of mind with certain highly peculiar material forms; the constant proportion which is found to subsist between the quantity of cerebral matter and the degree of intellectual capacity—a proportion which may be clearly traced throughout the ascending series of vertebrated animals, and which is very generally manifested in individuals of the human species; the effects of cerebral anæmia, anæsthetics, stimulants, narcotic poisons, and lesions of cerebral substance. There can, in short, be no question that the whole series of observable facts bearing upon the subject are precisely such as they ought to be upon supposition of the materialistic theory being true; while, contrariwise, there is a total absence of any known facts tending to negative that theory. At the same time it must be carefully noted, that the observed facts (and any additional number of the like kind) do not logically warrant us in concluding that mental states are necessarily dependent upon material changes. Nevertheless, it must also be noted, that, in the absence of positive proof of causation, it is certainly in accordance with scientific procedure, to yield our provisional assent to an hypothesis which undoubtedly connects a large order of constant accompaniments, rather than to an hypothesis which is confessedly framed to meet but a single one of the facts.