Science, as we have said, makes no assumptions save those which are necessary for her purpose, which is to ascertain and describe what actually takes place in Nature. Conversely, it is vain to imagine that from those assumptions anything can be deduced except conclusions of the kind which they are framed to cover, viz. conclusions as to what actually does take place. To say, therefore, that all knowledge--philosophy and religion--must become scientific before it can be regarded as trustworthy is simply to say that nothing can be regarded as true, except what is deduced from the assumptions of science: conclusions drawn from any other assumptions have no scientific truth. The assumptions of science are constructed only to lead to conclusions as to what is: we can therefore have no scientific, _i.e._ no real, knowledge of what ought to be. With the assumptions she makes, Science can only describe the way in which things happen; why they should so happen it is therefore impossible to know. The idea that all things are the expression of self-determining will is not one of the assumptions of science; no conclusions from it, therefore, can be considered valid. Without staying to consider why the unproved and unprovable assumptions of science are so superior to all others as to be set up as the sole source of truth, the only fount of genuine knowledge, let us consider what sort of a picture of the universe they give us. Perhaps a simile will best help us. Let us imagine a game of chess in course of being played by invisible players in presence of a scientific philosopher who knows nothing about the game--or who assumes that he knows nothing--except what his senses tell him. What he sees will be simply material chess-men moving in space. He may either consider them to be merely sense-phenomena, merely affections or modifications of his sense of sight and touch, or he may consider them to be real, material things. In either case he makes an assumption. The latter assumption leaves it quite an open question whether the reality is something insentient or is the expression of conscious will. The former precludes the question, _i.e._ assumes that there is neither conscious will nor insentient matter behind them.