A. SEDGWICK'S FALLACIES. 299 than that " He who asserts must prove," with the reservations and explanations, that whoever asserts that a thesis is false must accept a burden too, and that he who asserts a reason as suf- ficient, or claims that it is certainly insufficient, is in exactly the sauie position. The same holds good with him who asserts that an assertion is doubtful, and, moreover, he who asserts the most widely accepted doctrine cannot escape the " burden " of support- ing it by reasons. More than this cannot perhaps be said in a formal investigation, but it is worth spending a moment or two in seeing how the subject should be treated in a fuller inquiry into the principles of evidence. It has to be relegated to the field of Probability or Induction if we want to get clearer light upon the matter. Is it the fact that every proposition that can be uttered comes to us with a certain amount of presumption for or against it, which is to be incorporated along with the specific evidence or testimony, and duly allowed for in the determination of our assent ? The subject may be looked at from two points of view. From the psychological side it may be urged that the mind does and must entertain a determinate amount of belief on every subject pro- posed to it. This is claimed by De Morgan, who " takes it for granted that, . . . every proposition, the terms of which convey any meaning, at once, when brought forward, puts the hearer into some degree of belief " (Formal Logic, p. 193). But for such belief to be of any value there must of course be some physical or external justification for it, and the question would then be, Are things so united together by causation or other uni- formities that a really unique object or event cannot be found ? I think that this must be admitted to be the case. With even our present knowledge of nature it would be hard to find a pro- position as to which we should have to guess in blind and utter ignorance. Some ground, however slight, resting on Induction or Analog} 7 or Probability would almost always be found ; so that if the proposition could be submitted to a perfectly impartial umpire he might decide whether we were to put the initial belief as posi- tive or negative. Practically this is clearly out of the question, but it deserves notice that the failure does not so much depend (as might be currently supposed), upon the total absence of all connecting links, but rather on the fact of there being so many of them, all excessively slight perhaps and telling in opposite directions, so that the resultant is quite incalculable. The main outlines of the book may be indicated as follows : The possible objections to an assertion may be of three different kinds : (1) We may be met on the threshold by the objection that it is not capable of either proof or disproof owing to its " unreal " character, such unreality arising either from its being merely tautologous, or self-contradictory-, or involving terms which are devoid of meaning. (2) It may be objected that the Thesis is a mere assertion offered without support or justification. (It is
