But say you,surely there is nothing easier than to imagine trees,for instance,in a park, or books existing in a closet, and nobody by to perceive them. I answer, you may so, there is no dif?culty in it:but what is all this,I beseech you,more than framing in your mind certain ideas which you call books and trees, and at the same time omitting to frame the idea of anyone that may perceive them? But do you not yourself perceive or think of (...) them all the while? This therefore is nothing to the purpose: it only shows you have the power of imagining or forming ideas in your mind;but it doth not shew that you can conceive it possible, the objects of your thought may exist without the mind: to make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest repugnancy. (shrink)