The theory that organisms are the result of chemical and mechanical combinations, and that consciousness is a concomitant of some processes in the continuous existence of such physical combinations, throws all the burthen of explanation just as fully upon the line of physical causation as if there were no such concomitant of consciousness whatsoever. The determining causes are wholly physical, and the chain of sequence is complete within the lines of chemical and mechanical relations. The fact that independent and concomitant consciousness accompanies some of the actions in question is an interesting circumstance, but although consciousness is produced as an effect, it never on this theory produces any effects itself. The attempt to amend the conceptions of the original chemical factors (the sixty or seventy so-called elements,) and of the physical factors (heat, light, etc.,) by the association with them of mind, feeling, etc., has at various times produced vague theories. More particularly of later years Professor Clifford's theory of mind-stuff has attracted a great deal of attention. But, singular to say, Professor Clifford only endeavoured to work out his theory in some vague semi-mechanical, semi-subjective kind of way. It was not of such a sort that, given a nebula such as we supposed to be the predecessor of the solar system, we should be able to deduce from it the existing universe. The proper statement of such a problem would be a statement of the relations not merely of mind-stuff, but of mind-oxygen, mind-nitrogen, etc. The conception would have to be of such a nature as to express the mind-factor, mental side, or subjective aspect of oxygen, as related to the mind-factor of nitrogen, etc., and how they variously affected the conduct of the doubly-constituted atoms or of the more complex molecules into which they formed themselves. But this is a mere indication of the larger task of estimating the whole of the elementary substances, and estimating the value and the action of their relative mind-factors. From this would have to be determined the law of growth by which increasing complexity evolved the continually increasing power of the mind-factor in determining actions. Upon this might rest a rational basis for a definition of life of such sort that the organic could be recognised as arising out of the inorganic. And since the organic, in its latest and highest development, is mainly distinguished by purposed actions, purposed actions might be deemed to have evolved in a natural way out of actions which were not purposed. But such a theory is not capable of definite statement, and our philosophic object in endeavouring to account for the origin of purposed action out of non-purposed action is as far off as ever.