Finally, there is one other assumption made by the common faith of mankind and rejected by positive philosophies. It is that the world, _i.e._ everything of which man's consciousness is aware and to the reality of which his consciousness is evidence, is the expression of self-determining will, human and superhuman, manifesting itself directly to his consciousness. This assumption, too, has its counter-assumption--that there is no self-determining will, human or superhuman--and to reject the one assumption is to accept the other. To say that you do not know whether a man's word may be trusted or not is literally agnosticism, and may be the only rational attitude to assume, _e.g._ if the man is an absolute stranger, as most witnesses in court are to the judge who tries the case. But on the ground of your ignorance to refuse to pay any attention to his evidence when given is to abandon your agnosticism--if a judge directs the jury to disregard the evidence of the witness, the presumption is that he assumes it to be false. So, too, if we disregard the evidence of consciousness on this or any other point, we do not thereby succeed in avoiding assumptions, we only assume that consciousness is not trustworthy.[37] The idea that in philosophy it is possible permanently to maintain an agnostic attitude with regard to the trustworthiness of consciousness is the outcome of a conscientious attempt to apply scientific methods to the solution of philosophic problems. Science does not find it necessary to assume either that there is or that there is not a God: on either assumption it is certain that bodies tend towards each other at the rates specified in the gravitation-formula. Philosophy must be made scientific. Therefore philosophy must carefully avoid making either assumption. Why, the very reason why science has progressed and philosophy never moves is that science builds only on demonstrated fact, philosophy only on undemonstrable assumptions. Proof, and therefore truth, is impossible if you start from assumptions which never can be proved to be either true or untrue. The truth is that it is possible to maintain the agnostic attitude, and to avoid making assumptions, just so long as we do not need to form an opinion or take action on the matter which the assumption affects.