The whole point of science is that most of it is uncertain. That's why science is exciting--because we don't know. Science is all about things we don't understand. The public, of course, imagines science is just a set of facts. But it's not. Science is a process of exploring, which is always partial. We explore, and we find out things that we understand. We find out things we thought we understood were wrong. That's how it makes progress.
This is certainly true. However, it is also true that there ARE things that we do know. Otherwise, there would be no progress. We explore things that we don't understand based on the stuff that we know. It may turn out that as we learn more, the stuff that we know might become more of a special case, or a simplified case, as in what happened with Newton's laws, but we do know it works and when and where it works.
I happen to be in the camp where Dyson's controversial view on climate change isn't a big deal. I don't know why it created that much of a controversy, and it is also certainly not as if he had seriously did a scholarly research on it the way Richard Muller did. What is annoying is that this is done in the media, rather than among the experts, i.e. via publications in which all the experts can scrutinize everything. This is also part of science, and how science is practiced.