We have not been able to get out of this cave, but by looking long and hard at the shadows on the cave wall, we can at least make out the shapes of symmetries, which though broken, are exact principles governing all phenomena, expressions of the beauty of the world outside.Īlways, however great the height of the balloon, when I have seen the horizon it has roughly appeared to be on the level of the car though of course the dip of the horizon is a very appreciable quantity or the same height as the eye. In particular, we can study matter only at relatively low temperatures, where symmetries are likely to be spontaneously broken, so that nature does not appear very simple or unified. We are in such a cave, imprisoned by the limitations on the sorts of experiments we can do. But eventually their vision clears, and they can understand how beautiful the real world is. When released from the cave at first their eyes hurt, and for a while they think that the shadows they saw in the cave are more real than the objects they now see. In the seventh book of the Republic, Plato describes prisoners who are chained in a cave and can see only shadows that things outside cast on the cave wall. And nothing makes me more optimistic than the discovery of broken symmetries.
I suppose that I tend to be optimistic about the future of physics. Nor was it for want of a sufficient intensity of light that one of the two portions was incapable of producing the fringes alone for when they were both uninterrupted, the lines appeared, even if the intensity was reduced to one-tenth or one-twentieth. For, a little screen being placed a few inches from the card, so as to receive either edge of the shadow on its margin, all the fringes which had before been observed in the shadow on the wall, immediately disappeared, although the light inflected on the other side was allowed to retain its course, and although this light must have undergone any modification that the proximity of the other edge of the slip of card might have been capable of occasioning. Now these fringes were the joint effects of the portions of light passing on each side of the slip of card and inflected, or rather diffracted, into the shadow.
Besides the fringes of colour on each side of the shadow, the shadow itself was divided by similar parallel fringes, of smaller dimensions, differing in number, according to the distance at which the shadow was observed, but leaving the middle of the shadow always white. I brought into the sunbeam a slip of card, about one-thirtieth of an inch in breadth, and observed its shadow, either on the wall or on other cards held at different distances. For greater convenience of observation I placed a small looking-glass without the window-shutter, in such a position as to reflect the sun's light, in a direction nearly horizontal, upon the opposite wall, and to cause the cone of diverging light to pass over a table on which were several little screens of card-paper. I made a small hole in a window-shutter, and covered it with a piece of thick paper, which I perforated with a fine needle. No Runic legend, no Babylonish arrowhead, no Egyptian hieroglyph, no Moabite stone, could present a history like this, or suggest thoughts of such weighty import or so stimulate and exalt the imagination.Įxper. Every shadow was suffused with light shining from behind, suggesting some mighty achievement of knowledge of knowledge growing more daring in proportion to the remoteness of the object known of knowledge becoming more positive in its answers, as the questions which were asked seemed unanswerable. As I mused, the pale legend began to glow with life. I stood and mused, absorbed in the varying yet significant intensities of light and shade, bordered by mystic letters and symbolic numbers. He explained that they were carefully-prepared photographs of portions of the Solar Spectrum. remnants from a grandmother’s wedding dress.
They might be shreds of mummy-wraps or bits of friable bark-cloth from the Pacific. As I strayed into the study of an eminent physicist, I observed hanging against the wall, framed like a choice engraving, several dingy, ribbon-like strips of, I knew not what.
0 kommentar(er)
