WHAT CAN I KNOW AN INQUIRY INTO TRUTH, ITS NATURE, THE MEANS OP ITS ATTAINMENT, AND ITS RELATIONS TO THE PRACTICAL LIFE BY GEORGE TRUMBULL LADD, LL. D. LONGMANS, GREEN, AND CO. FOURTH AVENUE 30TH STREET, NEW YORK LONDON, BOMBAY, CALCUTTA AND MADRAS 1914 PREFACE f 1 1 HE asking of questions, and the con scious, persistent, and deliberate search J. L for their answers, is characteristically human. Even in the quest for the gratification of his appetites, the intellect, volitions, and tastes of man are involved in a quite different way from that which is the case with any of the lower animals. Only man makes a problem demanding thought and exciting anxiety out of the ques tions What shall I eat or, What shall I drink or, What shall I put on In answer-, ing these and all similar inquiries, he defers to customs that have established themselves, not merely in considerations of physical necessity, but also of propriety, aesthetical gratification, ind moral obligation. And these considerations lire themselves the fruits of reflection, if not on e part of the individual, at least on the part of e clan, tribe, or race, to which the individual fbelongs. But what is for our present purpose more im portant to notice, is this It is characteristic of human reason to ask and pursue the answer of fyet more abstract and deeply hidden questions. Some sort of interest in, and of inquiry into, the r 1 in PREFACE fundamental problems of science and philoso phy, has excited the minds of men from the very earliest traceable beginnings of human history. Nor are the motives for this interest wholly con fined to any imagined physical good or pleasur able, but as it were ab-extra experiences, which theirconjectural answer might promise to afford. The intellectual satisfaction which comes from asking and answering questions of . every sort and not by any means least, questions of the most difficult sort has operated to stimulate the human mind as much as the hope of gaining information available for the more successful conduct of the so-called practical life. Among the questions, the value of right answers to which is found both in the interest of intellec tual satisfaction and in the successful conduct of life, we may distinguish the following four as easily standing in the front rank. Tersely put in common language, they may well enough take the following form What can I know What ought I to do What should I believe What may I hope As expressed in this form, they are designedly made closely fitting to the exi gencies, the opportunities, and the interests of the individual man. As set in the moulds of the different main departments of philosophical dis cipline, the first and third of these questions might be called epistemological the second ethical, and the fourth, a question having to do chiefly with certain aesthetical and religious iv PREFACE experiences. It is as problems of the personal life that we are proposing briefly to raise and to discuss them. It would be a mistake, however, to think that any of these four questions can ever be raised, much less even provisionally and partially an swered, as other than as philosophical problems. But this is only to say that they are all problems of reflection, and reflective thinking is the method of all philosophy. Nay reflective thinking is, essentially considered, the very substance of philosophy. We might go still further and employinganother more offensive word say that they are all metaphysical problems. But we need not be troubled by this manner of desig nating them. For we may at once remind our selves of the truth which was clearly enough enunciated as long ago as Aristotle, namely that every man, inasmuch as he is a man, is also a philosopher. 4 If, then, we say to ourselves You must not philosophize, the answer of our com mon nature comes back And yet you must philosophize…