The Stoic Philosophy
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we need in each case is a “comprehensive sense-impression.” The meaning of this phrase is not quite clear. I think it means a sense-impression which “grasps” its object; but it may be one which “grasps” us, or which we “grasp,” so that we cannot doubt it. In any case, when we get the real imprint of the object upon our senses, then this imprint is of necessity true. When the Sceptics talk about a conjuror making “our senses deceive us,” or when they object that a straight stick put half under water looks as if it were bent in the middle, they are talking inexactly. In such cases the impression is perfectly true; it is the interpretation that may go wrong. Similarly, when they argue that reasoning is fallacious because men habitually make
