 The first tenet of Boyle’s philosophy of experiment is that observation and experiment should have epistemic priority over theory. That is, one should accept only those principles and axioms in natural philosophy that are based upon sufficient observational and experimental evidence and one should avoid constructing a theory without recourse to observation and experiment. Speculative philosophy commences with principles that are accepted without recourse to experiment, whereas experimental philosophy begins with observation and experiment and only then proceeds to theory.