​“PHILOSOPHICALLY SPEAKING…”:

This epistemological thought experiment, known as the Sleeping Beauty Problem, is from “1000-Word Philosophy,” a growing online collection of short essays created to make philosophical arguments accessible to the general public.

“Imagine that Beauty takes part in an experiment: on Sunday night, she is put to sleep. Then, the experimenters flip a fair coin. If the coin lands heads, Beauty is awakened on Monday, then is put back to sleep until the experiment ends on Wednesday. If the coin lands tails, Beauty is awakened on both Monday and Tuesday; however, after her Monday waking, Beauty is given a memory drug that makes her forget her Monday waking when she wakes up on Tuesday. This case sets up what’s called the ‘Sleeping Beauty Problem.’ Its question is: What degree of belief, or credence, should Beauty assign to the claim 'The coin landed heads' (call this H) when she awakens? .. Answers to the question of what Beauty’s credence in 'The coin landed heads' (H) ought to be are typically divided into two camps:

• 'halfers' say Beauty should assign H a credence of 1/2.
• 'thirders' say Beauty should assign H a credence of 1/3.

The 'problem' in the Sleeping Beauty problem is that it’s not clear which of these two solutions is correct or why.” The article goes on to describe the competing arguments of the “halfers” and the “thirders.”
https://1000wordphilosophy.com/2019/06/15/the-sleeping-beauty-problem/