MAN AND REALITY 187 and widely discussed. But there is one point about them by which a biologist cannot help being struck. The picture which emerges is of an observer contemplating a world from the outside, as Jupiter was supposed to contemplate Earth from the vantagepoint of heaven. The observer is not so much an individual human being-Sir James Jeans or Sir Arthur Eddington personally-but rather an artifici al creation-the human intellect, or perhaps better the human intellect as represented by the highest achievements of mathematical physics. And the world observed is not so much the concrete world as the ordinary man observes it, but a world with all its qualities taken out of it except what can be weighed and measured-a world of mass, space, time, and energy, a metrical, mathematical world.