I have noticed that there are a number of verbs in Japanese which have common alternative forms, especially potential form, but these forms have identical meanings.
One of these is 焼く, which appears to have similar if not identical meaning to its potential form 焼ける, although burning down and being able to burn down seem to be very different things from an English perspective.
Words which behave similarly include 続く/ 続ける, 入る/入れる, 受く/受ける, and I'm sure there are many more examples I've seen that don't come to mind right now.
What is the reason for these words having unchanged meanings despite seemingly changed forms? Are they even really etymologically related?