The title of Darwin’s book On the Origin of Species is often interpreted as if it is about the origin of life. It isn’t. It is about the evolution of life and how the different plant- and animal species have ended up looking the way they do today. Darwin did not know how life itself had originated. He did not have the material to examine that very issue, but that is not considered a weakness in the theory.
Scientific knowledge has boundaries. The questions, which lie outside those boundaries, neither can nor should be answered by science. The position, which Darwin took, is called scientific agnosticism – an expression which was introduced by Darwin’s good friend and colleague Thomas Henry Huxley. Today, we have several theories on the origin of life, but we still don’t know for sure how it happened. What we can establish so far – and so could Darwin – is that it happened at a certain point in time. The theory of evolution is about what happened after life on earth had originated.