This is a very interesting and very VALID objection: "Evolutionary process, as a theory, can't be falsified".
This is what I am up against, as I believe that evolution has happened on Earth's biosphere since day one. (A billion years ago, not six thousand years ago, day one being.)
Here's my reply:
Evolution has three tenets (neo-Darwinian evolution): 1. Life forms from parents to children are different due to genetic changes that happen either in a random fashion, or according to the rules of genetics. 2. Some genetic differences make new life forms that are more apt to survive in a given set of dominant conditions. 3. Genetic differences can genetically distance a lineage of offspring into a new species.
We can falsify the theory of Gravity by observing two masses repelling each other at close distances, due entirely to their masses. That has not been observed yet. So gravity can be falsified, but it has not happened yet.
How can we falsify evolutionary theory? By falsifying any one or more of its three mechanisms.
1. Genetic changes do not alter the life forms of offspring from parent. This would be a falsifier. But it does not happen: if a DNA gets altered, the offspring is not going to take the form of the parent. So this falsifying never occurred yet, so the theory stands.
2. Genetic changes gave rise to cats with no lungs, to headless snakes, to people with XXX chromosome triplets, to people born with Myelomeningocele, also known as open spina bifida, and none of these have survived in nature. These are all changes in the fetus developed due to altered DNA due to random mutation. If and only if any of these new mutations survived would then the second point be violated, or falsified. But it is not, because none of them did.
3. A succession of genetic differences will not distance species from the original, or in case of two streams of successions from genetic differences will not distance two species from each other. According to this, man and chimpanzee ought to be able to produce viable, surviving babies. But they are not, so this point has not been falsified, either.
Here were three different ways that the Evolyooshonary theory can be falsified. Validly. But this has not happened, not one of the named falsifications. Therefore the evolutionary theory stands.