PDF - Wallace Online

ix LIMITS OF NATURAL SELECTION IN MAN 207adopts the " well founded doctrine that life is the cause andnot the consequence of organisation." In his celebratedarticle " On the Physical Basis of Life," however, he maintainsthat life is a property of protoplasm, and that protoplasmowes its properties to the nature and disposition of itsmolecules. Hence he terms it "the matter of life," andbelieves that all the physical properties of organised beingsare due to the physical properties of protoplasm. So far wemight, perhaps, follow him, but he does not stop here. Heproceeds to bridge over that chasm which Professor Tyndallhas declared to be " intellectually impassable," and, by meanswhich he states to be logical, arrives at the conclusion thatour "thoughts are the expression of molecular changes in thatmatter of life which is the source of our other vital phenomena."Not having been able to find any clue in Professor Huxley'swritings to the steps by which he passes from those vitalphenomena, which consists only, in their last analysis, ofmovements of particlesof matter, to those other phenomenawhich we term thought, sensation, or consciousness, butknowing that so positive an expression of opinion from himwill have great weight with many persons, I shall endeavourto show, with as much brevity as is compatible with clearness,that this theory is not only incapable of proof, but is also, asit appears to me, inconsistent with accurate conceptions ofmolecular physics. To do this, and in order further todevelop my views, I shall have to give a brief sketch of themost recent speculations and discoveries as to the ultimatenature and constitution of matter.The Nature of MatterIt has been long seen by the deepest thinkers on thesubject, that atoms, considered as minute solid bodies fromwhich emanate the attractive and repulsive forces which givewhat we term matter its properties,could serve no purposewhatever ;since it is universally admitted that the supposedatoms never touch each other, and it cannot be conceived thatthese homogeneous, indivisible, solid units are themselves theultimate cause of the forces that emanate from their centres.As, therefore, none of the properties of matter can be due tothe atoms themselves, but only to the forces which emanate