It has been noticed in the two previous chapters how Eucken discovered the presence of a mental or spiritual life in the very act of knowing any object in the physical world. And the presence of such a life enables the percept to turn into a concept. Such a concept is something far removed from the level of the sensuous object or of its mere perception. We are in this very act in a world of _meaning_. When such a meaning comes to be acknowledged, it forms a kind of standard which interprets any future facts that enter into it. The further the progress of the knowledge of physical objects advances the more the concepts become removed from the level of the sensuous; as is witnessed, for instance, in the forms of laws and hypotheses, which constitute the very groundwork of physical science. The physical scientist, whether he is conscious of it or not, has constructed an ideal world of _meaning_ which constitutes the explanation [p.88] of the external world. This is a fact so familiar that it needs no further elucidation here. But there is great need for calling attention to the power which _does_ all this as well as to the reality of the interpretation which that power, in its contact with physical phenomena, has brought forth. That such a power of the mind is connected with physical existence does not in the least explain its nature. It is not physical _now_; it is meaning and value, and there is no such thing as meaning or value in the nature of physical objects in themselves. Their meaning and value come into being when they serve a purpose which the mind has framed concerning them. Eucken insists that a reality must be ascribed to so much as all this--to that which knows and interprets Nature. However much Nature and Spirit resemble one another, however much the latter is dependent on the former, Nature must be conceived as exhibiting a lower grade of reality than mind. Indeed, Nature could not exist for mind unless there were a mind to know it; and this fact inevitably leads us to ask the question, whether Nature could exist at all.[25]