A Bayesian View on the Dr. Evil Scenario.

Area of Science:

• Epistemology
• Philosophy of Probability

Background:

• Adam Elga proposed a principle of indifference for self-locating beliefs.
• This principle suggests equal credences for indistinguishable subjective states.
• Elga used thought experiments to justify this principle.

Purpose of the Study:

• To analyze the logical structure of Elga's justification for the principle of indifference.
• To evaluate the validity of Elga's reasoning using a Bayesian approach.
• To determine if Elga's principle can be derived from his thought experiments.

Main Methods:

• Bayesian analysis of philosophical arguments.
• Critical examination of thought experiments in epistemology.
• Logical assessment of self-locating belief principles.

Main Results:

• Elga's reasoning in his third thought experiment is circular.
• The justification relies on assuming the principle of indifference it seeks to prove.
• The principle of indifference cannot be derived as claimed.

Conclusions:

• Elga's defense of the principle of indifference is unsuccessful due to circular reasoning.
• While the principle of indifference is reasonable, its derivation is flawed.
• The Bayesian approach reveals the circularity in justifying self-locating belief credences.