the eyes; therefore it is impossible to say whether it is really pleasant or unpleasant.  In regard to myrrh it is the same, for it delights the sense of smell, but disgusts the sense of taste.  Also in regard to 93 euphorbium, since it is harmful to the eyes and harmless to all the rest of the body, we are not able to say whether it is really harmless to bodies or not, as far as its own nature is concerned.  Rain-water, too, is useful to the eyes, but it makes the trachea and the lungs rough, just as oil does, although it soothes the skin; and the sea-torpedo placed on the extremities makes them numb, but is harmless when placed on the rest of the body.  Wherefore we cannot say what each of these things is by nature.  It is possible only to say how it appears each time.  We 94 could cite more examples than these, but in order not to spend too long in laying out the plan of this book we shall simply say the following:  Each of the phenomena perceived by us seems to present itself in many forms, as the apple, smooth, fragrant, sweet, yellow.  Now it is not known whether it has in reality only those qualities which appear to us, or if it has only one quality, but appears different on account of the different constitution of the sense organs, or if it has more qualities than appear to us, but some of them do not affect us.  That it has only one quality might be concluded from what we 95 have said about the food distributed in bodies, and the water distributed in trees, and the breath in the flute and syrinx, and in similar instruments; for it is possible that the apple also has only one quality, but appears different on account of the difference in the sense organs by which it is perceived.  On 96 the other hand, that the apple has more qualities than those that appear to us, can be argued in this way:  Let us imagine someone born with the sense of touch, of smell, and of taste, but neither hearing nor seeing.  He will then assume that neither anything visible nor anything audible exists at all, but only the three kinds of qualities which he can apprehend.  It is 97 possible then that as we have only the five senses, we apprehend only those qualities of the apple which we are able to grasp, but it may be supposed that other qualities exist which would affect other sense organs if we possessed them; as it is, we do not feel the sensations which would be felt through them.  But 98 nature, one will say, has brought the senses into harmony with the objects to be perceived.  What kind of nature?  Among the Dogmatics a great difference of opinion reigns about the real existence of nature anyway; for he who decides whether there is a nature or not, if he is an uneducated man, would be according to them untrustworthy; if he is a philosopher, he is a part of the disagreement, and is himself to be judged, but is not a judge.  In short, if it is possible that only those qualities 99 exist in the apple which we seem to perceive, or that more than these are there, or that not even those which we perceive exist, it will be unknown to us what kind of a thing the apple is.  The same argument holds for other objects of perception.  If, however, the senses do not comprehend the external world, the intellect cannot comprehend it either, so that for this reason also it will appear that the suspension of judgment follows in regard to external objects.