Scientific method is an empirical method of knowledge acquisition, involving careful observation, formulating hypotheses based on such observations, testing deductions drawn from the hypotheses, and refinement or rejection of hypotheses based on the results of the tests.ext we have to know what “theory of evolution” we’re talking about. Let’s begin with the theory proposed by Charles Darwin in the Origin of Species.
I don’t know what “No assumptions here” in the question details is supposed to mean. Making hypotheses is part of the scientific method. Maybe it means that a hypothesis is assumed subject to verification, while an assumption is an axiom not subject to test. The scientific method makes testable hypotheses but never makes firm assumptions.
Darwin made a lot of observations. Then he made two hypotheses:
The observed variation among individuals can accumulate to produce all the differences we observe among species.
The effect of these variations on the ability of a living entity to survive and reproduce preserves some variations and eliminates others.
The heritability of variations was essential to the theory, but it was an observed fact, not an assumption or a hypothesis.