Meaning of "at an arm's length"

I am uncertain as for meaning of at an arm’s length in the following sentence. I have taken this example from an online philosophical magazine.

The answer seems clear at an arm’s length, but let us trace the
trajectory of the problem as it emerged prior to that opening
question.

In my opinion, at an arm’s length means, in this case, something like at first sight, so I would say that when something is or seems clear at an arm’s length, that would amount to saying that because something is close to us, we would be able to distinguish it in a clear way. I have, however, consulted on this with a native speaker and he said that for him this expression would mean here that the answer seems clear from a distant viewpoint. In any event, he takes the expression to mean, in this context, something like from a long distance. In my opinion, such meaning would not make sense taking into account what is being said after the preposition but. Certainly the expression at an arm’s length is here used metaphorically, but it seems that neither the literal nor the metaphorical sense of this expression could end up meaning something like "from a distant point of view". Or could this be the case?