Almost all scientific arguments for creationism consist of objections to evolution. The logic is that if evolution is not true, then creationism is true. While different creationists, or schools of creationism, may emphasize different points for rejecting Darwinian evolution, the following reasons are commonly cited among various adherents. Phillip E. Johnson, in his book Darwin on Trial, articulates the following points:
- After a century of intentionally breeding animals and plants, the variation that has been produced is limited; for example, dogs that are selectively bred are still dogs. Furthermore, when allowed to return to a wild state, bred characteristics experience a reversion suggesting that natural forces are less progressive than Darwin posited.
- Certain items in the universe, like the eye, could not have operated in a lesser form. To accept that the eye evolved would mean believing that for thousands of generations the individual parts that make up the eye as its now known continued to evolve into greater degrees of complexity although it was without function.
- The absence of "intermediate types" of fossils pose a problem for Darwinian evolution according to many creationists. Darwin himself acknowledge this absence and believed it was because not enough fossils had been discovered yet. Creationists also believe that "statis" - the fact that fossils look essentially the same over long periods of time - argues against Darwinian evolution. Also, "sudden appearance" - the fact that species appear suddenly in certain areas, rather than gradual - is also believed to argue against Darwinian evolution.
- Creationists do not believe adequate explanations have been given for the differences in molecular structures of living organisms. Furthermore, it's held that the argument of "similarities means common ancestry" has been overstated. While similarity suggests common ancestry to many Darwinian evolutionists, creationists argue that it could also mean the life forms have the same Creator.
- The greatest problem for evolution, according to many creationists, is that the theory does not explain how the universe began. Creationists often look to the metaphor offered by Fred Hoyle to articulate this argument: The chances that a living organism emerged by chance is the same as a tornado sweeping through a junk yard and assembling a Boeing 747." It is concluded that such a "chance assembly" is another way of saying "miracle."