In the most important sense a creationist is a person who believes in creation, and that includes people who believe that Genesis is a myth and that creation involved a process called evolution and consumed billions of years.
Phillip E. JohnsonScience...has become identified with a philosophy known as materialism or scientific naturalism. This philosophy insists that nature is all there is, or at least the only thing about which we can have any knowledge. It follows that nature had to do its own creating, and that the means of creation must have included any role for God.
Phillip E. JohnsonTruth as such is not a particularly important concept in naturalistic philosophy.
Phillip E. JohnsonFirst, Darwinian theory tells us how a certain amount of diversity in life forms can develop once we have various types of complex living organisms already in existence.
Phillip E. Johnson