You can never be absolutely certain that anything doesn't exist. But you can show that it's unlikely.
Richard DawkinsOnly a tiny fraction of corpses fossilize, and we are lucky to have as many intermediate fossils as we do. We could easily have had no fossils at all, and still the evidence for evolution from other sources, such as molecular genetics and geographical distribution, would be overwhelmingly strong. On the other hand, evolution makes the strong prediction that if a single fossil turned up in the wrong geological stratum, the theory would be blown out of the water.
Richard DawkinsReligious people split into three main groups when faced with science. I shall label them the "know-nothings", the "know-alls", and the "no-contests."
Richard Dawkins