Williamson argues that the central problem of epistemology is the problem of skepticism, which is the challenge of showing that we can have knowledge of the external world.

Williamson argues that the best way to respond to skepticism is to adopt a coherence theory of truth, which holds that the truth of a belief is determined by its coherence with other beliefs.

The main argument for the coherence theory of truth is the argument from coherence, which holds that the truth of a belief is determined by its coherence with other beliefs.

The main objection to the coherence theory of truth is the objection from circularity, which argues that the theory is circular because it defines truth in terms of coherence, which is itself defined in terms of truth.

Williamson argues that the objection from circularity is based on a misunderstanding of the theory, and that the theory can be reformulated in a way that avoids the objection.

Williamson argues that his theory of truth shows that knowledge and justification are both possible, but that they are not the same thing. He argues that knowledge requires truth, but that justification does not.

One of the main criticisms of Williamson's theory of truth is that it is too abstract. Critics argue that the theory is not grounded in the real world, and that it does not provide a practical way to determine the truth of beliefs.

Williamson's theory of truth is still considered to be an important contribution to epistemology because it provides a new way of thinking about the problem of skepticism, offers a new account of knowledge and justification, and has inspired new research in epistemology.

Williamson argues that evidence is neither necessary nor sufficient for the truth of a belief. He argues that a belief can be true even if there is no evidence to support it, and that a belief can be false even if there is evidence to support it.

Williamson argues that truth is necessary but not sufficient for knowledge. He argues that a belief can be true even if it is not known to be true, and that a belief can be known to be true even if it is not true.

Williamson argues that justification is necessary but not sufficient for knowledge. He argues that a belief can be justified even if it is not known to be true, and that a belief can be known to be true even if it is not justified.

Williamson argues that coherence is neither necessary nor sufficient for truth. He argues that a belief can be coherent even if it is not true, and that a belief can be true even if it is not coherent.

Williamson argues that his theory of truth is not circular. He argues that the theory can be reformulated in a way that avoids the objection from circularity.

Williamson argues that his theory of truth is both compatible and incompatible with other theories of truth. He argues that the theory is compatible with some theories of truth, such as the correspondence theory of truth, but that it is incompatible with other theories of truth, such as the pragmatic theory of truth.