MaximRecoil said:
You need to give actual evidence of your claim that Yoda was not being literal

Well, their whole conversation was about Luke's mindset, and Yoda trying to make him see things in a different way.
Clearly it is not power that Luke lacks, but the belief that it is possible.
Yoda was trying to get him to understand the nature of the force, which obviously conflicted with everything he already knew.

So how is it not a philosophical discussion? The Jedi are all about philosophy.

Yoda wasn't teaching him some specific Jedi-lifting trick, like “...moving stones around is one thing but this is totally different!”, “No, no different!, just remember to bend your knees and lift with you legs.” ;)

Yoda never implies that he is the perfect Jedi or force-user ("Strong am I with the Force… but not that strong").
So you could take it that Yoda is not all-powerful but he is wise enough to know that it is his own lack of faith in the force that prevents him from being that.