All of the great philosophers of the present era, beginning with Descartes, made the same mistake, and it colored their account of knowledge and indeed their account of pretty much everything. By ‘great philosophers’, I mean Locke, Berkeley, Hume, Descartes, Leibniz, Spinoza, and Kant. I am prepared to throw in Hegel and Mill if people think they are great philosophers too. I called this mistake the “Bad Argument”. Here it is: We never directly perceive objects and states of affairs in the world. All we ever perceive are the perceptual contents of our own mind.This confusion rests on jumping from the fact that Berkeley says we perceive "ideas," to concluding Berkeley believes what we perceive is "all in our heads." But here is George Pappas on Berkeley:
I know of no reason to think that Berkeley is committed to holding that each idea is private in the sense described. After all, any idea immediately perceived by a finite perceiver is also immediately perceived by God. So, Berkeley is committed to the contrary line, viz., that ideas are publicly perceivable entities.For Berkeley, the furniture of the world is objectively perceivable ideas, not ideas "in our heads."