General, or abstract, necessary truths. Three inches long are of equal length, because cach is a yard long." Truths about any objects different in number-for example, about groups of marbles; as that five marbles and five marbles make ten marbles--may be abstracted or enlarged first into the arithmetical, and afterwards into the algebraical "abstract" truths-five added to five make ten, or 5a+5a=10a. Just so the above two judgments about the two eyes and two sticks may be easily enlarged respectively into the "abstract" propositions: Nothing can, at the same time, both "be and not be," and "things which are equal to the same thing are equal to each other." These two general propositions will, on reflection, be seen, like the particular judgments from which they have been abstracted, to be certain without proof; they may, therefore, be said to be necessarily true or "necessary truths." Reflection will also show that we can have no certainty about anything if those abstract judgments are not absolutely certain. They are therefore truths which are necessary for our intellectual activity. orders of fundamental certainty. But we have already seen that absolute certainty does exist, and that, as a fact, we may validly argue in its defence. At the root, then, of all certainty, there must lie perceptions of three orders of truths all supremely certain and selfevident, namely, (1) perceptions of a greater or less number of general truths; (2) perceptions of particular facts; and (3) perceptions of the force of some arguments. If we had no certain knowledge of self-evident general truths, advance in knowledge would be absolutely impossible, and we could not argue; for if anything could be and not be at the same time, then something proved might at the same time be unproven. If we had no certain knowledge of any fact-as, for example, that we have some feeling or belief-all our demonstrations would, as it were, remain suspended in the air and have nothing to do with reality; and if there were no rcality, there could be no real truth, and therefore no certainty. Lastly, if the truth of some mode of reasoning was not clearly self-evident, we could never arrive at any conclusion, and all argument would be vain. But men of all schools of thought, who argue, show that they do not think all argument vain. The conclusion that any given man will ultimately die if mortality is the sure lot of all criterion evidence The most certain and indisputable judgments, then, are those which require no proof, but are self-evident. If any reader is still dissatisfied with self-evidence as the one criterion of ultimate truths, let him ask himself what other is a better better criterion, or ground of belief, ultimate truths could than possibly have. Any criterion provided as the test of an possible! ultimate judgment must either reside in the judgment itself, and so make it luminously self-evident, or in something external to it. Now, if some criterion external to it, indefinitely more perfect than anything we can think of, had been provided, we could only appreciate it through our perception of it and our judgment about it, and such judgment could not give us certainty unless it was selfevidently true. In this way, instead of being better off, we should but have self-evidence after all-and that once removed as a criterion. It will be plain on reflection that nothing external-no common consent of mankind, common sense, or testimony-could ever take the place of an ultimate criterion of knowledge, since some judgment of our own mind must always decide for us with respect to the existence and value of such criteria. The principle of evidence, then, is one which is really ultimate, and must be accepted under pain of complete intellectual paralysis. It is incapable of demonstration, since it depends on nothing else. It is constantly assumed unconsciously, and is acted on confidently by every one who reasons. We conform to it without thinking about it, but if we reflect on it we see three good reasons for assenting to it :-(1) The spontaneous and natural tendency of all men constantly to conform to it; (2) the destruction of all our knowledge and the impossibility of thinking logically at all, if we do not admit the legitimacy of the criterion; and (3) the fact that, by admitting it, we gain a foundation for our knowledge (which can thus become a mental cosmos instead of a chaos), and are enabled to progress in science. Our task, then, in the pursuit of truth itself should be, The task of after truth. the inquirer first, to discover what general principles, what particular facts, and what methods of reasoning are clearly selfevident, and therefore supremely true. When once these have been as far as possible ascertained, we may next proceed to elucidate by their help those truths, next in rank, which underlie all science, following this up with an examination of the teachings of science itself, in the supreme or highest sense of that word. Having accomplished that task, we shall have done all we can in the direct pursuit of truth, and may leave to the followers of each separate, subordinate science that indirect pursuit of it which consists in the investigation of the several orders of truths with which each separate science deals. All our knowledge must either be self-evident, or must be legitimately deduced from what is self-evident. In our pursuit of truth, our endeavour must be to proceed from the known to the unknown, not, of course, with the expectation of being able ever to know all things, but with a determination not to renounce beforehand the investigation of any problem which may seem to demand inquiry at our hands. CHAPTER II. SELF-KNOWLEDGE. The primary fact of our own continuous existence is known to us with supreme certainty, though, like our feelings, not explicitly so without the aid of reflection. What we first and directly perceive is our own momentary activity, but this perception implicitly contains the knowledge of both our existence and our feelings, which respectively and equally need, for their explicit cognition, a reflex mental act. First fundamental fact, self-knowledge-This commonly supposed certain-Need of considering arguments against its possibilityWhat these mean-Some truth in them-Also a false assumption and an error of fact-Mistake as to an implication-Self-knowledge like our knowledge of others-Primary cognitions-An objection-Met by a distinction-Explicit and implicit knowledge -Feelings cannot be known without self-knowledge-Feelings not known prior to self-A fundamental error and its consequences. IN the preceding chapter an endeavour has been made to bring home to the mind of the reader the truth that the supreme and ultimate criterion of the certainty of any proposition is its own luminous self-evidence. The first task of the inquirer after truth was also declared to be a search for the most certain general principles, facts, and methods of reasoning. The quest of truth, however, is the quest of what is eminently real; and so, to ensure reality, we will begin, not with the consideration of any "abstract principle," but of a "fact." mental fact, It is no unusual thing for a person to exclaim, with First fundareference to something about which he is sure, "I am as self-knowcertain of it as I am of my own existence; and the ledge. This commonly sup posed certain. exclamation is generally understood to denote a very high degree of certainty. The so often quoted Delphic precept, "Know thyself," has been explained in different senses by different writers; but there is just one thing in which all these writers agree, and that is that men can know themselves. There are, of course, some unfortunate persons, in a more or less diseased or idiotic state of mind, who, from defect of memory or whatever cause, are unable to recognize their own personal identity. But this book is addressed to reasonable men of ordinary intelligence, and not to those who are wholly or partially out of their minds; and, indeed, a plain man would very naturally consider any one to be "out of his mind" who sincerely professed that he could not know his own existence with entire certainty. It is, therefore, to be feared that some readers may be impatient at meeting with an argument directed to show that we have the fullest reason to be supremely certain of the fact of our own existence. They may at first very naturally feel disinclined to consider reasonings about a matter they have never themselves felt it possible to doubt, even if they have heard that other persons have been so "absurd" as to profess to doubt about it. "To doubt one's existence," they will say, "is even more absurd than to believe that one's limbs are made of glass!" And yet there are two arguments good reasons why no one who would earnestly inquire Possibility after truth, should refuse to consider carefully the arguments which follow. The first of these two reasons is that the question concerning the supreme certainty of the fact of our self-knowledge is of fundamental importance for the inquiry after truth. If that certainty cannot be established, then the inquiry after truth may, for reasons hereafter stated, be given up as one essentially insoluble. The second reason is the circumstance that very eminent, highly intellectual men have denied, and do deny, the supreme certainty of our self-knowledge. Now, it is not for a moment to be supposed that such men are insincere, or that they can adhere to a doctrine which does not contain some truth. It will probably, then, be worth while to try and find out what this truth is which they do hold, and to examine whether they have not overlooked some Need of considering against its |