It is however essential, if one is to appreciate a philosopher, to understand clearly what his main problem is. Therein lies frequently the differences among philosophers--that is, in the special emphasis laid on one problem, and the attention to, or neglect of other aspects. To fail to be clear on this matter frequently means to misunderstand a philosopher. And it would seem that many critics have failed to appreciate the work of Eucken to the extent they should, because they have expected him to deal in detail with problems which it is not his intention to discuss, and have failed to appreciate what special problem it is that he attempts to solve. Eucken's special problem is that of the reality in the universe, of the unity there exists in the diversity of things. In so far as he makes this his problem, he is at one with other philosophers in investigating what may perhaps be considered to be the most profound problem that the human mind has ever conceived. The fact that distinguishes Eucken from a large number of other thinkers is that he starts where they leave off. At a rule, philosophers begin their investigation with a consideration of matter, and proceed by slow degrees to attempt to explain the reality at the basis of it. Some never get further, and dispense with the question of human life and thought as mere aspects or manifestations of the material world. But the problem of life is for Eucken the one problem--he seeks to find the reality beneath the superficialities of human existence, and he has little to say concerning the world of matter. And, after all, it is the problem of life that urgently calls for solution, for upon the solution that is accepted, the life of the individual is to a large extent based. It is, of course, very interesting to meditate and speculate upon the material world, its origin and evolution, but the question is very largely one of mere theoretical interest--a kind of game or puzzle for studious minds. It is the question of life itself that is ultimately of practical interest to every human soul. And this is the problem that Eucken would solve. Hence those who expect to find a closely reasoned philosophy on matter and its manifestations must look elsewhere, for Eucken has little for them. Eucken's philosophy is a philosophy of life, and he only touches incidentally those aspects of philosophy that are not immediately concerned with his special problem. He refuses to be allured from the main problem by subsidiary investigations, and perhaps rightly so, for one problem of such magnitude would seem to be enough for one human mind to attempt. Eucken is a philosopher who lays foundations and deals with broad outlines and principles; it must be left to his many disciples to fill in any gaps that exist on this account, by attempting to solve the subsidiary problems with which Eucken cannot for the present concern himself.