Peirce is not pleasurable to read because he writes like the academic scientist he was 120 years ago. "Fixation of Belief" is his treatment of how and why we come to believe. I stumbled across it in my quest to find out why we believe anything at all. This quest became exceedingly urgent in the wake of "taking the class," domestic political fever, and the global pandemic.
He presents four methods we use in fixing our beliefs or resolving doubt. In ascending order, weakest to strongest:
1. Tenacity. If a doubt arises about X, take a particular position on X, constantly reiterate that position to yourself in a way that you begin to believe X, then shut out anything that might cause you to doubt X. [David Agler]
2. Authority. Victor said it, that settles it, I believe it.
3. Agreeable to Reason (a priori). We simply think through whatever doubt we have until we happen upon a belief that seems right to us. [David Agler]
4. Science. The scientific method.
For more on critical thinking, doubt, belief and curiosity, check out Anthony Magnabosco's fascinating channel about street epistemology.
https://youtube.com/c/AnthonyMagnabosco210