Ideally, I would like to see an article on the PF insights about the scientific process about how we come up with laws, theories, and hypothesis. May be I missed, if so, please point me to the right page. My specific questions are as follows: Is there a lab experimental evidence a must to accept a hypothesis into a theory? I guess it is not needed. As an example, even though we have not simulated big bang theory in the lab, it is still a theory. I guess when someone initially proposed the big bang theory, it must be a hypothesis. And what specific observation made it into a theory. I'm assuming there is no center body that determines if a hypothesis could be made into a theory or not. Please correct if I'm wrong here. In Biology, theory of evolution is a theory, because we have lots of forensic/dna evidences to support it, or is it because we were able to successfully show the genetic variation in the lab experiments? I was reading about Katharine Milton's "Meat-eating was essential for human evolution hypothesis" (https://nature.berkeley.edu/miltonlab/pdfs/meateating.pdf) Why is it a hypothesis, whereas theory of evolution is a theory, even though she provides forensic/biological explanations for her hypothesis? My answer to that was, we cannot reproduce Milton's claim in the lab, so it is a hypothesis. But then the question comes, even big bang is not reproducible in the lab. Is there difference in the criteria between Physics and Biology, in what makes into a theory from a hypothesis?