That is very true that with our current scientific knowledge we can not understand everything, and even those things that we (think that we) understand do not provide a good picture of some of the observations.
However, what Randi is suggesting is very pleasing. He is claiming that if anyone could provide some measurable psychic effect, he will give him/her 1 million dollar. As one of the measurable experiment that he has in mind is to make predictions about something like a coin flip. Say they flipped coins many times and psychic person guessed correctly 52% of the time. Given enough trials, that percentage would be enough. Or in one other place he (Randi) asks, if someone just by looking at picture could say the person is dead or alive is another testable measure to win the prize. The experiments look very easy to perform and all are based on deviation from fair random selection.
That is true that there are many things that we do not know, and there are many things that we see and can not explain, but this should be the source of our curiosity and not the source of our deception. Especially, his (Randi’s) emphasize on the role of mass media in spreading “not tested claims” in a nice and fancy cover is very important to notice.
A friend of mine reminded me that there are some experiments suggesting some unexplainable effects, for example PEAR lab in Princeton, however some evidences in some experiments has not much in common with what psychic claims. What I understood is that people like Randi are against those people who makes claims about some (deterministic) “super/unnatural power” while they are not even trying to prove it. Sadly, there are many people who fall for these people. By paying to those people we are supporting them, so they get more powerful and once they have all the power, it is very hard to stop them. For example, homeopathic people should try to explain why he did not fall into deep sleep after taking 22 pills (assuming those pills are what he claims to be).
There is a huge difference between experimenting something and practicing something. In my opinion the path is rather clear. We should move toward understanding what we don’t know based on what we know. However, all society wide practices should be based on what we know, or at least we think we know.
I should have also mentioned that some of the skeptics make it hard (and sometimes impossible) for others to pursue new directions which may deviate from the main stream experiments. However, the presence of experiment such as PEAR lab experiment, shows that there are ongoing experiments in this direction (however not many). Dogmatism is against any progress in understanding and we should stay away from that. However, we should not get confused between being open minded and supporting balloonies. I believe we should continuously reexamine what we consider as “knowledge” and keeping eye for new developments.