It's human intelligence at work. The process is honest, because every researcher's claim is challenged by other researchers. They test and retest by many methods, until a new idea fails or holds firm. While some individual scientists are pig-headed, an entire field cannot be. Science goes where the evidence leads.
Science is honest enough to admit mistakes.
When new evidence shatters a previous assertion, the old belief is dropped or modified. No such setbacks have hit the theory of evolution. After 140 years of research, virtually the entire scientific world now agrees that evolution is a fundamental aspect of nature. Complex animals and plants arose from earlier, simpler ones, over hundreds of millions of years. The fossil record shows it.