Fichte, who certainly was not easily satisfied with anything, begins to treat of the basis of human knowledge by making an affirmation, and this he confesses with an ingenuousness that does him honor. Speaking of reflection, the foundation of his philosophy, he says: "The rules to which this reflection is subject, are not proved to be valid, but are tacitly presupposed to be known and admitted. They are, in their remotest origin, derived from a principle, the legitimacy of which can only be established on condition that _they are valid_. This is a circle, but an _inevitable circle_. But supposing it to be inevitable, and that we frankly confess it so to be, it is, in order to establish the highest principle, allowable _to trust all the laws of general logic_. We must start on the road of reflection with a proposition conceded by all the world without any contradiction."[1] [1] Fichte, _Grundlage der gesammten Wissenschaftslehre_. Theil. i., § 1. Ed. Berlin, 1845, p. 92. 9. Certainty is to us a happy necessity; nature imposes it, and philosophers do not cast off nature. Pyrrho once came very near being hit by a stone, but he very naturally took good care to get out of its way, without stopping to examine whether it was a real stone, or only the appearance of one. The bystanders laughed at him for this, and, at the same time, showed how inconsistent this act was with his doctrine; but he gave this answer, which, under the circumstances, was exceedingly profound: "It is hard entirely to throw off human nature." 10. In sound philosophy, then, the question turns not upon the existence of certainty, but upon its motives, and the means of acquiring it. It is an inheritance of which we cannot divest ourselves, although we repudiate those very titles which guaranty its possession to us. Who is not certain that he thinks, feels, wills; that he has a body, and that there are around him others similar to his, of which the corporeal universe consists? Prior to all systems, humanity was in possession of this certainty, so, also, is every individual, although he may never during his whole life have once asked himself what the world is, what bodies are, or in what sensation, thought, and will consist. Not even if we examine the foundations of certainty and acknowledge the serious difficulties concerning them, which arise from ratiocination, is it possible to doubt everything. There never was, in all the rigor of the word, a true skeptic.