How can we accept the physical theory of light and believe at thesame time that information about an external object must be conveyedby light? The latter is implied whenever we say that the object stimulatesthe eye. The outline of an answer was suggested in Chapter 1 (pp. 12-13,14-15). We can escape the paradox by distinguishing between radiantlight and ambient light - that is, between light emitted from an energysource and light reflected by the environment as a source. The convey-ing of information about surfaces by light of the latter kind is conceiv-able. To justify such a theory, however, the known laws of physicaloptics need to be supplemented with quite unfamiliar laws of ecologicaloptics
Argues that distinguishing between
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"radiant light" (light emitted from an energy source)
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"ambient light" (light reflected by the environment as a source)
resolves issue of - wanting a physical theory of light - wanting info about objects to be conveyed by light
But needs ecological optics to be combined with physical optics to justify this theory.