There is no impression nor idea of any kind, of which we have any consciousness or memory, that is not conceived as existent; and it is evident, that from this consciousness the most perfect idea and assurance of being is derived.  From hence we may form a dilemma, the most clear and conclusive that can be imagined, viz. that since we never remember any idea or impression without attributing existence to it, the idea of existence must either be derived from a distinct impression, conjoined with every perception or object of our thought, or must be the very same with the idea of the perception or object.

As this dilemma is an evident consequence of the principle, that every idea arises from a similar impression, so our decision betwixt the propositions of the dilemma is no more doubtful. go far from there being any distinct impression, attending every impression and every idea, that I do not think there are any two distinct impressions, which are inseparably conjoined.  Though certain sensations may at one time be united, we quickly find they admit of a separation, and may be presented apart.  And thus, though every impression and idea we remember be considered as existent, the idea of existence is not derived from any particular impression.

The idea of existence, then, is the very same with the idea of what we conceive to be existent.  To reflect on any thing simply, and to reflect on it as existent, are nothing different from each other.  That idea, when conjoined with the idea of any object, makes no addition to it.  Whatever we conceive, we conceive to be existent.  Any idea we please to form is the idea of a being; and the idea of a being is any idea we please to form.

Whoever opposes this, must necessarily point out that distinct impression, from which the idea of entity is derived, and must prove, that this impression is inseparable from every perception we believe to be existent.  This we may without hesitation conclude to be impossible.

Our foregoing reasoning [Part I. Sect. 7.] concerning the distinction of ideas without any real difference will not here serve us in any stead.  That kind of distinction is founded on the different resemblances, which the same simple idea may have to several different ideas.  But no object can be presented resembling some object with respect to its existence, and different from others in the same particular; since every object, that is presented, must necessarily be existent.

A like reasoning will account for the idea of external existence.  We may observe, that it is universally allowed by philosophers, and is besides pretty obvious of itself, that nothing is ever really present with the mind but its perceptions or impressions and ideas, and that external objects become known to us only by those perceptions they occasion.  To hate, to love, to think, to feel, to see; all this is nothing but to perceive.