Of such thinkers the number is daily increasing. There are now, probably, tens of thousands of more or less instructed men and women in this country who would call themselves rationalists in the broad sense above specified as now generally current. They are all, probably, Darwinians or evolutionists, mostly 'monists' in Spencer's way, 'determinists' in the philosophic sense of that term if they have worked at the 'free-will' problem at all, and non-believers in personal immortality. Very few, at least, bracket the term 'rationalist' with 'spiritualist' in describing themselves: the two tendencies nearly always divide sharply, though it cannot be said that in strict logic they are mutually exclusive. Of most, the philosophic attitude approximates broadly to that of Spencer, though many recognise and avow the inexpertness of Spencer's metaphysic. Only a few, probably, if any, could properly be termed 'skeptics' in the strict philosophic sense of doubters of all inferences. That is a mental attitude more often professed by defenders of 'revelation,' as Pascal and Huet, who seek to make the judgment despair of itself in preparation for an act of assent which is already discredited by such despair. Yet it belongs to the rationalistic attitude to be ready, in consistency, to analyse all one's own convictions and listen candidly to all negations of them. A belief in the possibility of rational certitude is implicit in every process of sincere criticism; but the discrimination or gradation of certitudes is the task of rational philosophy. As we shall see, quasi-rational certitude as regards the process of evolution is challenged from two points of view by professed believers in the reality of that process. One school argues that scientific conclusions are all uncertain because the ultimate assumptions of science are unverifiable, and that, accordingly, religious assumptions, being neither more nor less rational than others, may 'reasonably' stand. Others argue that the process of judgment or reasoning which is held to establish scientific truth is not adequate to any theory of interpretation; and that, accordingly, some species of divination--which in the terms of the case eludes judgment--is to be relied on. Such thinkers ostensibly profess to 'reason' to the effect that reasoning is invalid. Against them, those who claim to hold by reason as the totality of judgment may fitly call themselves by the name 'rationalist.'