actual one can be.
The eye may be said to owe its existence to light, which calls forth, as it were, a sense that is akin to itself; the eye, in short, is formed with reference to light, to be fit for the action of light; the light it contains corresponding with the light without.
We are here reminded of a significant adage in constant use with the ancient Ionian school—"Like is only known by Like;" and again, of the words of an old mystic writer, which may be thus rendered, "If the eye were not sunny, how could we perceive light? If God's own strength lived not in us, how could we delight in Divine things?" This immediate affinity between light and the eye will be denied by none; to consider them as identical in substance is less easy to comprehend. It will be more intelligible to assert that a dormant light resides in the eye, and that it may be excited by the slightest cause from within or from without. In darkness we can, by an effort of imagination, call up the brightest images; in dreams objects appear to us as in broad daylight; awake, the slightest external action of light is perceptible, and if the organ suffers an actual shock, light and colours spring forth. Here, however, those who are wont to proceed according to a certain method, may perhaps observe that as yet we have not decidedly explained what colour is. This question, like the definition of light and the eye, we would for