If I'm trying to decide what person he is in a sentence, I am making a

inference.

What kind of inference?

analogy:

an inference that if things agree in some respects they probably agree in others

corollary:

(logic) an inference that follows directly from the proof of another proposition

derivation:

a line of reasoning that shows how a conclusion follows logically from accepted propositions

deduction, entailment, implication:

something that is inferred (deduced or entailed or implied)

extrapolation:

an inference about the future (or about some hypothetical situation) based on known facts and observations

presumption:

(law) an inference of the truth of a fact from other facts proved or admitted or judicially noticed

abstract thought, logical thinking, reasoning:

thinking that is coherent and logical