There are no sensory `data'. Rather, there is an incoming challenge from the sensed world which then puts the brain, or ourselves, to work on it, to try to interpret it. Thus, at first, there are no data: there is, rather, a challenge to do something; namely to interpret. Then we try to match the so-called sense data. I say `so called' because I don't think there are sense `data'. What most people hold to be simple sense `datum' is in fact the outcome of a most elaborate process. Nothing is directly `given' to us: perception is arrived at only as a result of many steps involving interaction between the stimuli which reach the senses, the interpreting apparatus of the senses, and the structure of the brain. So, while the term `sense datum' suggests primacy in the first step, I would suggest that, before I can realize what is a sense datum for me (before it is ever `given' to me), there are a hundred steps of give and take which result from the challenge presented to our senses and our brain.
Karl Popper, The Self and Its Brain, p. 430.
Popper clarifies the statement above further when he calls a gene a mere theory about how to respond to external stimuli. In other words, the elaborate process that delivers up what you seem to think of as simple sense data is not so simple or unchallengable since the genetic design of the eye is itself theoretical. Using electromagnetic wavelengths as guideposts for perceiving the external world has been effective for many organisms, but only a scientific illiterate believes electromagnetic wavelengths possess the color added as a quality (
qualia) by the genetic design of the brain. There's no color in the universe. It's only a quality - a facade --affected by the brain.
We could say the first step in coming to grips with reality is to let loose the organ of our faux-masculinity, so to say, and start looking at the world aright. Those who won't let go of their toy might as well keep stroking since they're already blind and thus can't be threatened with impending blindness for doing what makes them feel good.
John