No, it is fact. Genetic mutations occur. And when they occur, not "if" they do, if they benefit the organism with the mutation, it will be better at surviving and reproducing than its fellow organisms. This isn't just an idea, it's a fact. New species don't just magically appear.
Let me inform you. Not all positive mutations result in an increasing genetic line from the benefiting individual.
On a related note, it is important to realize where scientific fact turns into speculation and when something is supported by current evidence, but is not, by any means, the only possibility.
Mutations can occur. They can be passed on. A new species can be eventually created. Evolution is real. These things have been observed. It is reasonable to conclude, only from this evidence, that evolution occurred in the past. There is also a lot more evidence to support evolution in the past. Is evolution the origin of the species? Likely most species come from evolution. Is evolution the origin of life? It is certainly possible, but there are many other possible sources.
Evolution: Certain (Observed)
Evolution in the past: Nearly certain (The evidence is here and also, why would the past be different with something so fundamental?)
Origin of the species: Nearly certain that most of them came as a direct product of evolution (It seems unlikely that a myriad of creation events occurred throughout the history of Earth)
Origin of life: It is possible (Evolution, in theory, would have no trouble creating life)
