We have therefore discovered the ambiguity of the copula in _esse_ is _percipi,_ so far as to see that this principle asserts two distinct terms to be so related, that whatever has the _one,_ which I call _esse,_ has _also_ the property that it is experienced. It asserts a necessary connexion between _esse_ on the one hand and _percipi_ on the other; these two words denoting each a distinct term, and _esse_ denoting a term in which that denoted by _percipi_ is not included. We have, then in _esse_ is _percipi,_ a _necessary synthetic_ proposition which I have undertaken to refute. And I may say at once that, understood as such, it cannot be refuted. If the Idealist chooses to assert that it is merely a self-evident truth, I have only to say that it does not appear to me to be so. But I believe that no Idealist ever has maintained it to be so. Although this--that two distinct terms are necessarily related--is the only sense which 'esse is percipi' can have if it is to be true and important, it _can_ have another sense, if it is to be an important falsehood. I believe that Idealists all hold this important falsehood. They do not perceive that _Esse_ is _percipi_ must, if true, be _merely_ a self-evident synthetic truth: they either identify with it or give as a reason for it another proposition which must be false because it is self-contradictory. Unless they did so, they would have to admit that it was a perfectly unfounded assumption; and if they recognised that it was _unfounded,_ I do not think they would maintain its truth to be evident. _Esse_ is _percipi,_ in the sense I have found for it, _may_ indeed be true; I cannot, refute it: but if this sense were clearly apprehended, no one, I think, would _believe_ that it was true. Idealists, we have seen, must assert that whatever is experienced, is _necessarily_ so. And this doctrine they commonly express by saying that 'the object of experience is inconceivable apart from the subject.' I have hitherto been concerned with pointing out what meaning this assertion must have, if it is to be an important truth. I now propose to show that it may have an important meaning, which must be false, because it is self-contradictory.