In the past, I have argued that there is no such thing as 100% confident human knowledge. Everything that we know comes laden with assumptions. There is no way around this.
Part of this is the question: How do we know that the human mind works? That human logic works? That science, which depends on human logic, also works?
While science must assume that science is possible and therefore cannot prove that, it does not follow that science cannot give us any confidence at all in our own abilities. In fact it has done just that: the astonishing successes of science and the groundbreaking technologies based on them have given those of us in the Western world immense confidence in our own brilliance and the brilliance of science.
The potential problem here can be shown using an analogy: goldfish science. Imagine a goldfish tank with a handful of goldfish, some pebbles and a novelty plastic castle. Goldfish Science believes that the entire world is made out of plastic castles. The evidence? That plastic castle in their fish tank! Also, goldfish can push the pebbles together to make castle-like structures. So the theory is proven, not just by the evidence but also by its practical usefulness.
Obviously this is terribly stupid, but who will tell the goldfish? Other goldfish certainly can’t. To be truly confident in their science, the goldfish need a superior intelligence to vet it for them.
It is highly likely that our science doesn’t have the extreme credibility problem that goldfish science has, but this doesn’t rule out more subtle problems. Until a superior intelligence vets our science for us, there will always be a reason to have doubts about the scientific project.