Peirce developed his unified semiotic account of both analytic and synthetic inference from interpreting classical (deductive) entailment as a species of a broader category of representation-relation. It presupposes that representation is a fundamental conception, irreducible to any other(s).
How did he arrive at this thesis? And what arguments did he offer to support it? To answer these questions, I focus on exploring Peirce's early treatment of truth. Defining truth as a property of representations (1861-2, W 1: 79), Peirce proceeded to analyze the constitution of representation following from its being possibly true.
Alongside that he sketched-out a metametaphysical idea of 'primal truths' (1861-2, W 1: 64) being conditions making any (including metaphysical) truth-claim possible. My exegesis aims to show how (particularly) these two early fragments combined make up the foundation of what later became Peirce's Semiotic, and what is their bearing upon the argument for the irreducibility of representation.