After darwin proposed his ideas about natural selection as a mechanism for evolution, it took time before evolution was generally considered a theory. why do we now refer to it as a theory? (1 point) fewer scientists agree with darwin's ideas now than they did at first, so it is called a theory. questions still remain concerning its validity, so it must be called a theory. enough supporting evidence has accumulated for it to be called a theory. the meaning of the word 'theory' has changed since darwin's time, and it fits the new meaning.