Philosophy of Knowledge: Clifford’s Rule, Hypotheses, and Skepticism

Clifford's Rule (CR)

It is wrong always, anywhere, for anyone, to believe anything, upon insufficient evidence.

Socially significant belief

A belief that can affect the welfare of someone rather than the believer.

Hypothesis

Anything that may be proposed to our belief.

Live hypothesis

Psychologically possible to accept.

Option

A decision between two hypotheses.

Live Option

A choice between two live hypotheses.

Forced Option

One must choose one or the other hypotheses.

Momentous Option

A unique and reversible choice of personal significance.

Genuine Option

An option that is live, forced, and momentous.

The Method of Doubt

Try to doubt each belief. If you can doubt a belief, then it isn't certain knowledge. If it can't be doubted, then it isn't known with certainty.

Sensory beliefs

Beliefs based on sense experience (visual, auditory, tactile, experiences).

a priori beliefs

Beliefs not based on sense experience.

Dream Hypothesis

I am now asleep in my bed having a very vivid dream.

Evil Demon Hypothesis

I'm now being systematically deceived by an all-powerful evil demon.

Self-Verifying belief

BIV Hypothesis

I am a bodiless brain in a vat being fed vivid experiences by a mad scientist's supercomputer.

External World Skepticism

We know very little about the external world outside our own minds.

Closure

If you know that p entails q, then if you know that p then you know that q.