The scientific method. The necessity that a hypothesis needs to be proven through testing and observation before it can be accepted as knowledge; something that is known.

And, hypothesis, that haven't been tested, can't be trusted as knowledge, but are just assumptions, even though they may be good assumptions. Evolution is a falsified theory. "Descent with modification from a common ancestor" requires that the common ancestor be able to be confirmed through testing and observation before the theory can be accepted as knowledgeable.

Otherwise, the rules of science label it an unconfirmed assumption. Evolution is falsified by observation. The theory requires a common ancestor for all the millions of species on Earth, but not a single common ancestor has been found. There are fossils that are assumed to be descendants of a common ancestor, but you can't validate a theory with an assumption. The Big Bang is a model and not a theory. A model is part of the process of constructing a theory. The theory then must be tested and validated before it can be accepted as knowledge.

It is ignorance of the rules of science to present Evolution, or the big bang, as science. ignorance: 'a lack of knowledge, understanding, or education : the state of being ignorant' assume: 'to think that something is true or probably true without knowing that it is true' If one accepts an assumption as true, without requiring validation, then they are still in a state of ignorance.