What is the core difference between internalism and externalism?

Internalism requires that whatever justifies a belief be accessible to the believer on reflection or fixed by their mental states; externalism allows justification to turn on facts the believer cannot access, such as whether the belief was formed by a reliable process.

What is the new evil demon problem?

It imagines a subject whose experiences are exactly like ours but systematically deceptive. Intuitively their beliefs are as justified as ours, yet their belief-forming processes are unreliable, which appears to count against reliabilist externalism and in favour of internalism.

Internalism and Externalism about Justification

This debate asks whether the factors that make a belief justified must lie within the believer's cognitive grasp — accessible to reflection — or whether they can include facts about the world, such as the reliability of how the belief was formed, that the believer need not be aware of.

Definition

Internalism about justification is the thesis that whatever determines whether a belief is justified is internal to the believer and accessible on reflection, while externalism denies this, allowing justification to depend on external conditions such as the reliability of the belief-forming process.

Scope

The topic covers the internalism/externalism distinction as applied to justification: access internalism and mentalism on one side, process reliabilism and other externalist views on the other. It includes the access argument and the new-evil-demon and clairvoyance problems that test each side, and the relation of the debate to the analysis of knowledge. Reliabilism's role as a response to Gettier and its application to specific sources are developed in neighbouring topics.

Core questions

Must the grounds of a justified belief be accessible to the believer on reflection?
Can a belief be justified by a reliable process the believer knows nothing about?
Does a victim of a deceiving demon, whose experiences are normal, have justified beliefs?
Should justification be understood mentalistically, as fixed by one's mental states?

Key theories

Access internalism / mentalism: On internalist views, justification is fixed by factors the believer can become aware of through reflection; evidentialism, a mentalist form, holds that justification is determined entirely by the evidence in the believer's present mental states.
Process reliabilism: Goldman's externalist account holds that a belief is justified when it is produced by a reliable cognitive process — one that tends to yield true beliefs — whether or not the believer can identify or access that process.

History

The distinction crystallised in the 1970s and 1980s as Goldman's reliabilism offered a thoroughly externalist account of justification, breaking with the internalist assumption inherited from Descartes that the grounds of belief lie open to introspection. Evidentialists defended a refined internalism, and the resulting debate became one of the organising axes of late-twentieth-century epistemology.

Debates

The new evil demon and clairvoyance cases: Internalists press the new-evil-demon problem, arguing that a deceived subject with normal-seeming experiences is intuitively justified though their processes are unreliable; externalists press clairvoyance cases, where a reliable but inaccessible faculty seems to yield knowledge, each side claiming the intuitions favour its view.

Key figures

Alvin Goldman
Earl Conee
Richard Feldman
Laurence BonJour

Seminal works

goldman1979
coneefeldman1985

Frequently asked questions

What is the core difference between internalism and externalism?: Internalism requires that whatever justifies a belief be accessible to the believer on reflection or fixed by their mental states; externalism allows justification to turn on facts the believer cannot access, such as whether the belief was formed by a reliable process.
What is the new evil demon problem?: It imagines a subject whose experiences are exactly like ours but systematically deceptive. Intuitively their beliefs are as justified as ours, yet their belief-forming processes are unreliable, which appears to count against reliabilist externalism and in favour of internalism.