The empiricist claim that all concepts and substantive knowledge derive from experience, Locke's attack on innatism and the tabula rasa, Hume's impressions and ideas and the missing shade of blue, the rationalist case for innate concepts and a priori knowledge, and the analytic, synthetic, a priori and a posteriori distinctions.

What this dot point is asking

AQA wants you to set the empiricist claim (all concepts and all substantive knowledge come from experience) against the rationalist claim (some concepts are innate and some substantive knowledge is a priori), to use Locke and Hume on the empiricist side and the innatist and intuition or deduction arguments on the rationalist side, and to handle the four distinctions: analytic, synthetic, a priori and a posteriori.

The four distinctions

The empiricist account

Hume himself raises the missing shade of blue: someone who has seen every shade of blue but one could arguably form the idea of the missing shade without ever having the impression. He concedes this is a counterexample to the copy principle but treats it as too trivial to abandon the principle. The case matters more than Hume admits, because if the mind can generate even one simple idea without a matching impression, the empiricist test of meaning loses its sharp edge, and the rationalist can press that other concepts might be produced the same way.

The empiricist account does real work as a theory of concepts as well as of knowledge. Locke's tabula rasa explains how a single mechanism, experience plus the mind's innate capacities to perceive, compare, combine and abstract, can build the whole stock of human concepts without positing mysterious innate furniture. The argument is partly an appeal to parsimony (innate ideas are an unnecessary posit) and partly an explanatory challenge (every concept the rationalist calls innate, the empiricist offers to derive from experience). Where the derivation looks strained, as with causation, substance and the self, the debate becomes a tug of war over whether the empiricist story is genuinely available.

The rationalist response

• Innate concepts. Some concepts (substance, causation, God, infinity) cannot be straightforwardly traced to impressions, so the rationalist argues they are innate, perhaps triggered rather than caused by experience.
• Intuition and deduction (a priori knowledge). Descartes argues we can grasp some truths by the natural light of reason: clear and distinct intuitions (such as the cogito) and what is validly deduced from them count as substantive knowledge gained without sense experience.
• Innatism via the slave boy. Plato's Meno has an untaught slave boy "recollect" geometry under questioning, which is offered as evidence that the knowledge was latent rather than learned from experience.

Empiricist replies and the analytic line

Empiricists argue that apparently innate or a priori knowledge is either analytic (true by definition, and so empty of substantive information about the world) or really a posteriori after all. Hume's fork divides all reasoning into relations of ideas (a priori, analytic, certain) and matters of fact (a posteriori, synthetic), leaving no room for synthetic a priori knowledge of the world.

The rationalist's best counterexample is mathematics. "Seven plus five equals twelve" looks both a priori (we do not check it by experiment) and synthetic (Kant argued the concept of twelve is not contained in the concepts of seven, five and addition), which would be exactly the synthetic a priori knowledge Hume's fork denies. Empiricists reply either that such truths are analytic after all, unpacking definitions in a way that only seems informative, or, following later logical empiricists, that mathematics is true by convention. The slave boy in the Meno faces a parallel deflation: the empiricist points out that Socrates leads the boy with carefully chosen questions, so the boy may be reasoning from premises he already grasps through experience rather than recollecting innate knowledge. Whether these deflationary readings succeed is the heart of any evaluative answer.