Spinoza’s “adequate ideas” is structural truth
An adequate idea is one that grasps a thing through its cause. For example, the planets move in ellipses because of the law of gravity” not just “I see them move. Truth, here, is the necessity of relations: if X exists under Y conditions, then Z necessarily follows. This is not representational, not “there are bright points in the sky”. It’s causal/logical necessity.
Kant’s development
Kant radicalizes this by saying that those necessary relations are not out there, but the way reason structures all experience. Causality, substance, quantity, unity, necessity are categories are the logical skeleton of our phenomenal world. Truth, then, is logical consistency of judgments within these structures: if you say “the sun warmed the stone,” you must apply causality.
Spinoza’s “adequate causal ideas” foreshadow Kant’s transcendental categories. Both point to structural truth which is necessity of relations, not pictorial truth.
