Truthmakers and Fundamental Facts

Core Idea

Truthmakers are entities in virtue of which propositions are true; fundamental truthmakers explain truths without relying on further truths. This framework connects semantic truth to metaphysical structure, raising the question of which facts are truly fundamental and what makes complex truths true given only fundamental truths.

How It's Best Learned

Work through examples of composite truths (conjunctions, conditionals, negations) and determine what minimal truthmakers would need to exist for each to be true.

Common Misconceptions

Assuming every true proposition must have a truthmaker in some domain (truthmaker maximalism). Confusing truthmakers with causes or explanations of why propositions are true.

Explainer

From your prerequisites on grounding and fundamentality, you know that the world has a hierarchical structure: some facts are fundamental and others hold in virtue of the fundamental facts. From your work on facts and truthmakers, you know the truthmaking relation: a truthmaker for a proposition is something in the world in virtue of which that proposition is true—not merely evidence for it, but the very entity or fact that makes it true. Putting these together, the central question becomes: what are the truthmakers for all true propositions, and can they all ultimately be traced back to fundamental facts?

A key insight is that truthmakers need not mirror the complexity of the truths they make true. For the proposition "This ball is red," the truthmaker might simply be the ball with its property of redness. But consider "Either it is raining or it is sunny"—a disjunction is made true by a truthmaker for either disjunct, so the existence of rain suffices. Consider "There are seven planets"—this seems to require the existence of seven distinct objects. The project of truthmaker theory is to systematically map the logical structure of propositions onto the structure of reality, determining which kinds of entities—objects, properties, relations, states of affairs, tropes—are needed as truthmakers for the full range of true statements.

The hardest cases are negative truths. What makes "There are no unicorns" true? It cannot be any positive entity—unicorns are precisely what is absent. One response is truthmaker maximalism: insisting that every true proposition must have a positive truthmaker, leading to positing "totality facts"—the fact that the things that exist are all the things that exist—as truthmakers for negative truths. But many philosophers find totality facts metaphysically suspicious. Alternative views deny that negative truths require truthmakers at all, holding instead that they hold in virtue of the absence of false-making entities, not the presence of true-making ones.

The connection to fundamentality transforms this into a full research program. If grounding has a bottom level, then fundamental truthmakers are those at the base of the hierarchy: they make truths true without themselves holding in virtue of anything more basic. Every derivative truth should be traceable upward through the grounding structure to the fundamental level. This gives metaphysics a precise task: identify which facts are genuinely fundamental—candidates include fundamental physical facts, facts about properties or laws of nature—and show how all other truths are grounded in them without remainder.