That question is a pandora's box that can't be given the nuance it deserves in an HN comment so I'll leave you with the Plato encyclopedia entry on naturalism [1] which was a philosophical debate which wrestled with this very topic in the first half of the 20th century. The vast majority of scientists and philosophers default to the definition from physicalism [2]

[1] https://plato.stanford.edu/entries/naturalism/

[2] https://plato.stanford.edu/entries/physicalism/