Usage of 誰でも and 誰にも


I was recently corrected from using 誰でも→誰にも in this sentence:

> それは決して否定できないことであって、（誰にも〇・誰でも？）分かる自明の理。

What's the difference between the two? This [HiNative
post](https://hinative.com/ja/questions/67111) says that 誰でも is usually used
for affirmation while 誰にも can be used for either affirmation or negation.
However, the above sentence does use 誰でも with an affirmative sentence. Does
誰にも simply sound more natural? If so, why?

Also, does this mean 誰でも can never be used with negation? Would a sentence
like「誰でもできないこと」be wrong?




I asked my wife, a native speaker about your question, and she agreed with
you. She said 誰でも is actually correct in your original sentence because it is
affirming (肯定文) in your statement. 誰にも, on the other hand, would imply the
opposite, a negative statement (否定文), and hence sounds strange in that
context. 自明の理 requires agreement, something that is known by everyone.




I asked my wife, a native speaker about your question, and she agreed with
you. She said 誰でも is actually correct in your original sentence because it is
affirming (肯定文) in your statement. 誰にも, on the other hand, would imply the
opposite, a negative statement (否定文), and hence sounds strange in that
context. 自明の理 requires agreement, something that is known by everyone.

