> entertain a thought without accepting it
Entertaining an idea is understanding it. And, there is some research to show that understanding an idea is believing it. Hence, understanding an idea and not believing it is very effortful.
[1] https://bear.warrington.ufl.edu/brenner/mar7588/Papers/gilbe...
> The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.
-- F. Scott Fitzgerald, The Crack-Up[1], Esquire, February 1936
[1] https://www.esquire.com/lifestyle/a4310/the-crack-up (https://web.archive.org/web/20250328074803/https://www.esqui...)