It will be readily understood that a hypothesis of this kind, which is apparently in violent conflict with the plainest facts of our daily personal experience, and gives the lie to that consciousness of freedom which we all possess, would not be held in theory--it cannot be acted on in practice--unless it appeared to be the consequence of some well-established facts. It is, of course, held by its supporters to be a logical consequence from the uniformity of nature and the law of universal causation, and to be a necessary pre-supposition if we are to give any scientific account of human nature and its evolution. If, as we have argued at length in this chapter, that is not the case, if the law of universal causation only requires that a thing cannot take place unless the requisite conditions combine--and not that conditions, which did or may combine, were or are bound to combine--the question still remains, what if any value the hypothesis has on its own intrinsic merits. In the first place it is a hypothesis which can never either be proved or disproved. The hypothesis is that our supposed consciousness of freedom is an illusion, that if we imagine we are free to choose what we will do, or that we could in the past have chosen otherwise than we did, we are deceived. The hypothesis is not based on any facts of consciousness: it is a suggestion that consciousness may be deceptive. It may: there is no means of proving or disproving the suggestion, for any reply must proceed from one consciousness to another, both of which are suspected by the maker of the suggestion to be not wholly trustworthy. We cannot ask him to concede to us, in order that we may convince him by argument, the very point which is in dispute. In the next place, the hypothesis of necessity does formally account for all the facts which it is designed to explain: it accounts for the whole process of evolution. If everything that happens does so because it must, then the mere occurrence of any step in the process carries its own explanation with it: the mere fact that it occurred shows that it was bound to occur. If we ask, "Why was it bound to occur?" the answer is, "Because it was." Various intermediate reasons may be interpolated--because everything must have a cause, and every cause must have its effect--but if we ask, "Why must everything have a cause? why must every cause produce its effect?" the ultimate answer is always, "It must because it must." If we ask, "What proof is there that it must?" there is none. As we have already said, the hypothesis is one which does not admit either of proof or disproof.