Over at Edge.org, there's the annual article on the subject of science, and several academics of various fields (including some names that are well-known here) have submitted essays based on a single question put forward. The article is entitled: "What Scientific Idea is Ready for Retirement?"
I bring this up for two reasons. Firstly, to bring the article to your attention in case you haven't seen it but might be interested. Secondly, as a lead-in to a broader question about the retirement of ideas.
Are there any ideas - chiefly scientific, but maybe philosophical too - that you think should just die, or at least be confined to history? Perhaps you are convinced, like Eric R. Weinstein, Frank Tipler, and Peter Woit (in his own fashion) from the article mentioned above that string theory has had its day? Maybe you think repression and other Freudian frameworks are just plain nonsense that need to be dropped, as David G. Myers does? Or maybe you agree with Lisa Barrett, Richard Dawkins, and Peter Richerson, though they approach it from different angles, and think essentialism is a flawed conception of the world that needs to be replaced by something less ethereal and more grounded?
The issue is yours to choose. The question is: What big scientific idea (or not-so-scientific idea, if you prefer) do you think needs retirement?