Читать книгу The Form Within - Karl H Pribram - Страница 62

Resolution of the question “Is there a retinal image?” came in a flash while I was crossing a busy street in Edmonton. I had been asked to present the MacEachron lectures at the University of Alberta, Canada, lectures which were subsequently (1991) published as a book, Brain and Perception. The fourth lecture concerned processing by the optical structures of the eye. I had explained to my audience that the lens of the eye performs a Fourier transform: on one side of our lens is a space-time image as we experience it; on the other side of the lens is a holographic-like spectral distribution. If indeed there is a space-time retinal image, as I had seen in the ox eye, the input to the eye must be spectral. This explanation fit nicely with David Bohm’s physics: as I mentioned earlier, Bohm had noted that if we did not have lenses, the universe would appear to us as a hologram.

However, Gibson’s intuition regarding a retinal image, and my uncertainty about it, remained unresolved. As my hosts and I were crossing a very busy street after the lecture, discussing the issue, the answer suddenly became clear and we stopped short in the middle of the street: The retina is not a film. The retina is a multilayered structure that is sensitive to single quanta, photons of visible radiation. Quantum properties are multidimensional. Gibson may have been wrong in emphasizing the idea that there is no image at all, but he was correct in his intuition regarding visual processing as multidimensional from the start.

The optical image is, as Gibson pointed out, actually an optical flow. In addition, the image is somewhat “blurred,” diffracted due to the gelatinous properties of the lens of the eye. (Technically, this blurring is called an “Airy disk.”) Thus the optical image that appears at the surface of the retina is somewhat spectral in configuration. The retinal quantum process completes the transformation into the spectral domain.

Separating the optical image (or flow, the moving image) from the retinal quantum process is in tune with Gibson’s intuition, which can now be developed in its entirety as follows:

1 Radiant energy (such as light and heat) becomes scattered, spectral and holographic, as it is reflected from and refracted by objects in the universe.

2 The input to our eyes is (in)formed by this spectral, holographic radiant energy.

3 The optics of our eyes (pupil and lens) then perform a Fourier transformation to produce a space-time flow, a moving optical image much as we experience it.

4 At the retina, the beginning of another transformation occurs: the space-time optical image, having been somewhat diffracted by the gelatinous composition of the lens, becomes re-transformed into a quantum-like multidimensional process that is transmitted to the brain.