inadmissibility of the eternity of the Universe would be equally self-evident, and would not require for its proof any other proposition. This, however, is not the place for investigating the subject. Twelfth Proposition. “The senses are not always to be trusted.” For two reasons the Mutakallemim find fault with the perception of the senses. First, the senses are precluded from perceiving many objects, either on account of the smallness of the objects—this is the case with the atoms, as we have already stated—or on account of the remoteness of the objects from the person who desires to perceive them; e.g., we cannot see, hear, or smell at a distance of many miles; nor do we perceive the motion of the heavens. Secondly, the senses misapprehend the objects of their perception: a large object appears small from a distance; a small object immersed in water appears larger; a crooked thing appears straight when partly placed in water, and partly out of it; things appear yellow to a person suffering from jaundice; sweet things are bitter to him whose tongue has imbibed red gall; and they mention many other things of this kind. Therefore they say, we cannot trust our senses so far as to establish any proof on their perceptions. You must not believe that the Mutakallemim had no purpose in agreeing upon this proposition, or as most of the later adherents of that school affirm, that the first Mutakallemim had no ulterior object in endeavouring to prove the existence of atoms. On the contrary, every proposition here mentioned is indispensable; if one of these be rejected, the whole theory falls to the ground. The last-mentioned proposition is of particular importance; for when our senses perceive things by which any of the foregoing propositions are confuted, the Mutakallemim say that no notice should be taken of the perception of the senses so long as the proposition is supported by the testimony of the intellect, and established (as they believe) by proof. Thus they say that the continuous motion is interrupted by moments of rest; that the millstone in its motion is broken into atoms; that the white colour of a garment ceases to exist, and another whiteness comes in its stead. All these theories are contrary to what the eye perceives, and many inferences are drawn from the assumed existence of a vacuum, all of which are contradicted by the senses. The Mutakallemim, however, meet these objections by saying, whenever they can do so, that the perception of these things is withheld from the senses; in other instances they maintain that the contradiction has its source in the deceptive character of the senses. You know that this theory is very ancient, and was the pride of the sophists, who asserted that they themselves were its authors; this is stated by Galenus in his treatise on natural forces; and you know well what he says of those who will not admit the evidence of the senses.