It is not to be supposed that anyone was to be found who denied the general intelligibility of Nature. To have done this would have been to reduce science to an absurdity. Science is bound to proceed upon the assumption that there are "reasons" for things. Moreover, there is mind in man, who is part of the order of Nature. It follows that what is in the part cannot be denied to the whole. All this could be freely admitted. But then the question arose, Is mind the originating source of the movements of matter, or is it not rather itself the product of them? {31} There were those who did not shrink from affirming that matter produces thought, even as the liver secretes bile. Others preferred to take what seemed to be an intermediate course. They were not prepared to give priority to either mind or matter. Thus Haeckel maintained that matter and thought are only two different aspects, or two fundamental attributes of an underlying something which he defined as "substance." It was to the action of this universal substance that he imagined the "monistic mechanical process" to be due. He went so far as to state his conviction that not even the atom is without "a rudimentary form of sensation and will."[3] In like manner Tyndall had claimed a two-sidedness for matter, and traced all higher developments back to the side which held in it the element of spirit and thought; while admitting that "the production of consciousness by molecular action is quite as inconceivable on mechanical principles as the production of molecular action by consciousness."[4] The bearing of all this upon the question of Design was plain, for, if thought and intention are the outcome and result of the mechanical operations of Nature, it might well seem to follow that mind {32} had been removed from its high place as the dominant and directing power.