So 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.