physical. But can we subject the mental process of perception to the same purification? Can we separate these two elements, the consciousness and its object, retain the element consciousness and reject the element object, which is physical, thus constituting a phenomenon entirely mental, which might then be possibly placed beside the entirely physical phenomenon, so as to study their relation to each other? This is quite impossible, and the impossibility is double, for it exists de facto and de jure.
De jure, because we have already established that a consciousness empty and without object cannot be conceived. De facto, because the existence of the object that consciousness carries with it is very embarrassing for the materialist; for this object is material, and as real and material as the fibres and cells of the brain. It might, indeed, be supposed that by transformation or otherwise there goes forth from the cerebral convolution a purely psychical phenomenon resembling a wave. But how can we conceive the transformation of this convolution into a semi-material phenomenon? How can we comprehend that there should issue from this convolution the material object of a perception—for example, a plain dotted with houses?
An English histologist remarked one day, with some eloquence, how little the most minute study