A phrase to describe on someone who foolishly convinces you he’s intelligent?

A person came to another holding an apple in his hand, and reaching it to the person facing him. “I know what’s on your mind, because using the method of Psychology I made you think ‘why you are giving an apple to me?’”confidently flattered himself, the guy thought he impressed someone for another day.

Any good phrase to ridicule such person?

Not sure, but maybe this could help -

It's not common, but sciolist seems to have the required definition.

One who exhibits only superficial knowledge; a self-proclaimed expert with little real understanding.

I prefer this to sophist, which I think has a suggestion of deceit rather than just ignorance or error.

^{Source: Word for someone seeming deep and intelligent, but not really being that}