The Senses as Condensing Complex Information

The function of the senses, Ayn Rand holds, is to sum up a vast range of facts, to condense a complex body of information---which reaches our consciousness in the form of a relatively few sensations. We perceive a bunch of roses, for example, as red, cool, fragrant, and yielding to the touch. Such sensations are not causeless. They are produced by a complex body of physico-chemical facts, including the lengths of the light waves the roses reflect and absorb, the thermal conductivity of the petals, the chemical makeup of their molecules, and the type of bonding between them; these facts in turn reflect the underlying atomic structures, their electronic and nuclear features, and many other aspects. Our sensations do not, of course, identify any of these facts, but they do constitute our first form of grasping them and our first lead to their later scientific discovery. Science, indeed, is nothing more than the conceptual unravelling of sensory data; it has no other primary evidence from which to proceed.^[1]

All sense data is valid in this sense: the senses don't distort, nor can they. The fact that different creatures have different means of perception does not invalidate this: no matter the means of perception, said perception is a perception of something that is. It is on the conceptual level that error occurs:

Conceptualization involves an interpretation that may not conform to reality, an organization of data that is not necessitated by physical fact; one can, therefore, "think about nothing," i.e., nothing real, such as a perpetual-motion machine or demonic possession or Santa Claus. But the senses sum up automatically what is.^[2]