[a proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena, either asserted merely as a provisional conjecture to guide investigation (working hypothesis) or accepted as highly probable in the light of established facts.]
1. I exist. [I think, therefore I am. ~ Rene Descartes]
2. My senses are sometimes accurate. [All justified beliefs are justified by physical evidence.]
3a. Only beliefs that are justified by evidence are valid.
3b. Belief strength is proportional to evidence amount.
3c. Evidence-based beliefs are validated through re-examination.
ALL THIS (AND MORE) IS EXPLAINED IN THE FOLLOWING TWO VIDEOS: