Class 8: Uncertainty & Probability Theory: The Logic of Science: What Probability Is 1

Lesson 8: What Probability Is 1.

We start by answering an excellent question.

Anon asks:

"I have a question about Bayes' Theorem and philosophical arguments. I ask because I have a broad scholastic approach to philosophy that relies metaphysical demonstrations.

"Is the contrast between probabilistic vs deductive arguments unhelpful? It seems like deductive arguments mask the uncertainty of probable premises. If each premise of an eight-step argument is 95%, the lower bound would be 66% (given independence).

"For some reason, this doesn't sit right with me. Bayes' Theorem seems useful for when deciding theories within the world, but not applicable to first principles (like the reality of change). But I don't have much of a mathematical background. Any assistance you can provide would be extremely welcome."

This leads us to show probability, being logic, doesn't care about the premises. Just about the CONNECTIONS between premises and the proposition of interest.

HOMEWORK: THERE IS NO SUCH THING AS UNCONDITIONAL PROBABILITY, I.E. THERE IS NO Pr(A), only Pr(A|B). If you think not, find a Pr(A)!

All questions will be answered in the following Monday's lecture.

Written lecture: https://www.wmbriggs.com/post/51635/
https://wmbriggs.substack.com/

Permanent class page: https://www.wmbriggs.com/class/