What are primary truths? According to Mr. Stewart:
"They are such and such only, as can neither be proved nor refuted by other propositions of greater perspicuity. They are self-evident; not borrowing the powers of reasoning to shed light upon themselves."
We are naturally inclined to consider the reality of our personal existence. That we exist is the great basis upon which we build everything. It is the foundation of all knowledge. Without self-existence nothing could result in the progress of the understanding.
If any man questions the fact of his own existence, that very process by which he doubts, proves to a demonstration, that an existing, doubting power must have been precedent, must have had a creation. The first internal thought is immediately followed with an undoubting conviction of personal self-existence.*
It is a primary truth in nature, and requires no further explanation.