Berkeley next faces a New Question which his New Principles are intended to answer. How is the concrete world that is presented to our senses related to Mind or Spirit? Is all or any of its reality independent of percipient experience? Is it true that the phenomena of which we are percipient in sense are ultimately independent of all percipient and conscious life, and are even the ultimate basis of all that is real? Must we recognise in the phenomena of Matter the _substance_ of what we call Mind? For do we not find, when we examine Body and Spirit mutually related in our personality, that the latter is more dependent on the former, and on the physical cosmos of which the former is a part, than our body and its bodily surroundings are dependent on Spirit? In short, is not the universe of existence, in its final form, only lifeless Matter? The claim of Matter to be supreme is what Berkeley produces his Principles in order to reduce. Concrete reality is self-evidently unreal, he argues, in the total absence of percipient Spirit, for Spirit is the one realising factor. Try to imagine the material world unperceived and you are trying to picture empty abstraction. Wholly material matter is self-evidently an inconceivable absurdity; a universe emptied of all percipient life is an impossible universe. The material world becomes real in being perceived: it depends for its reality upon the spiritual realisation. As colours in a dark room become real with the introduction of light, so the material world becomes real in the life and agency of Spirit. It must exist in terms of sentient life and percipient intelligence, in order to rise into any degree of reality that human beings at least can be at all concerned with, either speculatively or practically. Matter totally abstracted from percipient spirit must go the way of all abstract ideas. It is an illusion, concealed by confused thought and abuse of words; yet from obvious causes strong enough to stifle faith in this latent but self-evident Principle—that the universe of sense-presented phenomena can have concrete existence only in and by sentient intelligence. It is the reverse of this Principle that Berkeley takes to have been “the chief source of all that scepticism and folly, all those contradictions and inexplicable puzzling absurdities, that have in all ages been a reproach to human reason(469).” And indeed, when it is fully understood, it is seen in its own light to be the chief of “those truths which are so near and obvious to the mind, that a man need only open his eyes to see them. For such I take this important one to be—that all the choir of heaven and furniture of the Earth, in a word, all those bodies which compose the mighty frame of the world, have not any subsistence without a Mind” (sect. 6). Living Mind or Spirit is the indispensable factor of all realities that are presented to our senses, including, of course, our own bodies.