17. But truly when I hear that there are three kinds of questions, "Whether a thing is? -- what it is? -- of what kind it is?" I do indeed hold fast the images of the sounds of which these words are composed, and I know that those sounds passed through the air with a noise, and now are not. But the things themselves which are signified by these sounds I never arrived at by any sense of the body, nor ever perceived them otherwise than by my mind; and in my memory have I laid up not their images, but themselves, which, how they entered into me, let them tell if they are able. For I examine all the gates of my flesh, but find not by which of them they entered. For the eyes say, "If they were coloured, we announced them." The ears say, "If they sounded, we gave notice of them." The nostrils say, "If they smell, they passed in by us." The sense of taste says, "If they have no flavour, ask not me." The touch says, "If it have not body, I handled it not, and if I never handled it, I gave no notice of it." Whence and how did these things enter into my memory? I know not how. For when I learned them, I gave not credit to the heart of another man, but perceived them in my own; and I approved them as true, and committed them to it, laying them up, as it were, whence I might fetch them when I willed. There, then, they were, even before I learned them, but were not in my memory. Where were they, then, or wherefore, when they were spoken, did I acknowledge them, and say, "So it is, it is true," unless as being already in the memory, though so put back and concealed, as it were, in more secret caverns, that had they not been drawn forth by the advice of another I would not, perchance, have been able to conceive of them?