I am not very happy with most of the answers here as they seem to be too ideologically motivated and not so much about scientific reasoning. So I decided to give it another try.
Is Evolution really a fact and not just a theory?
If this is too long for you, let me just say this:
Evolution is an existing phenomenon. There is variation, there is selection and inheritance of traits. This has been studied and there is no scientific doubt that evolution is a process that is happening now and all the time.
Note that I intentionally bolded the word scientific. The rest of may answer will be mostly about science.
In science just a theory is not meant in a pejorative way. Everything that can be disproved, but scientist have not been able to disprove is a theory. The important part is that it must be possible to disprove theories by scientific methods.
In a way you can think of the principle of gravity also as just a theory. If you happen to find mass that does not get attracted by other mass, you would be able to prove <PERSON> wrong. But the evidence of the existence of gravity is so overwhelming that I would not spend too much energy on that :)
So - from a scientific view evolution is a theory with overwhelming scientific evidence. There is so much evidence that among scientist this debate is settled, just like the theory of gravity. The vast majority of the scientific community accepts the theory of evolution as the theory which is most probable to shape life here on earth.
But the attentive reader may have spotted a problem in the last sentence: There is an unlimited number of theories that can explain how the life shaped to a way that we can admire it today.
Long ago people realized that the most important part of a scientific theory is that it must be somehow possible to disprove it. Of course we can create a theory that contradicts gravity where a green-yellowish rectangular slime pushes objects together. Scientists will be able to disprove as long as it is falsifiable.
But if we now give the slime the sneaky attribute that it escapes human senses, we have a perfectly valid theory that cannot be disproved. 781
So if someone would ask you if it is 100% sure that <PERSON>'s theory of gravity is correct, what would you answer? You cannot simply dismiss the theory of the green slime, can you?
Okay back to science. Science basically tells you: You can and you even have to dismiss any theory that is not falsifiable. Theories that cannot be disproved are not valid in a scientific sense. Back to your question:
He goes on to say that man and chimpanzees both evolve from apes. Is he 100 % correct?
Is he 100% correct? - Certainly not, we can make a slimy theory that works as well.
Okay, so let's put it in a different way: Is he 100% correct in a scientific sense - This we cannot answer. There may be many now unknown scientific theories that explain life in its current form equally well. But at the moment we only have evolution.
So why then are scientists so sure? Why does <PERSON> tell us all the time that evolution is real?
Well scientists are pretty convinced because of two things: Firstly, a lot of scientific evidence has been collected to support the theory of evolution. There are fossils, there is genetic information, there are experiments that validate certain aspects. But what is even more important: Until now nobody could come up with an experiment disproving the key aspects of the theory of evolution.
There is a second important point here: At the moment we don't have any competing scientific theory. The theory of evolution in science is a little like olympia with just one participant. If someone wants you to bet on the winner, what would you do?
I acknowledge that there are non-scientific theories that can explain all aspects of existence equally well, but I want to strongly emphasize that these are NOT scientific theories. You do not have to accept science as an important explanatory system. But if you do, I hope I could convince you that scientific reasoning of scientists regarding evolution makes sense and although there is no way to quantify this believe in 90%, 99%, 99.9% or 100%, there is overwhelming evidence that make people like <PERSON> such firm proponents of the theory of evolution. 350