But it's not falisfiable, so it shouldn't be included into science according to you all...if it is falsifiable then tell me what observation or experiment would show that natural selection is false...
Darwinian natural selection is falsifiable, because in principle one could find evidence that (i) genes are not randomly mutating and/or that (ii) reproductive pressures were not favoring certain of the mutations that yielded a survival advantage. Stated differently, you could either find evidence that the genomes of living things were basically fixed and static within certain limits or that those individual changes play little or no role in determining what individuals survive in the long run. Either one would put the nail in Darwin's theory of natural selection.
"Falsifiable" does not mean that the hypothesis under review can be disproved with a single, smoking gun, observation (though that might be the case in certain instances). In the case of natural selection, no one observation can falsify it, but that doesn't make it unfalsifiable.
On the other hand, "God did it" is unfalsifiable, because God gets invoked as an explanation for almost anything. God makes it rain, He punishes the wicked, He rewards the virtuous, but He also makes it not rain, He rewards the wicked and punishes (or "tests") the virtuous—all in equal measure. We sum up all His actions we can't explain rationally with "God works in mysterious ways," but in the end all that means is that God works in ways that are so incomprehensible to us that we cannot predict them, nor use them to in any way conclusively demonstrate that He is having any direct or indirect effect on the universe at all.
In principle, "God did it" can be a plausible explanation to a believer for anything at all or any series of things, good or bad, positive or negative. In contrast, if unfit creatures start surviving in droves with the more fit dying off, at some point even believers in natural selection have to start admitting that those creatures are anomalous exceptions to the rule. If you build up enough such exceptions, then you show, in effect, that natural selection cannot be the significant cause of the diversity of life.
It just so happens that most life seems to be very well adapted to the niche it fills...that might be because God designs them (and why would God design them to be maladapted?), but it also fits natural selection...and it happens to leave natural selection (Darwinian or not) almost unassailable on scientific grounds.
Of course the well adapted outcompete the maladapted—it's almost a tautology (since the "one that survived" may often be dubbed the "well adapted" one by virtue of its survival alone). Even if natural selection were a crock, that would likely be true. So one is very unlikely to disprove natural selection by disproving "the survival of the fittest."
Good news for natural selection though, it doesn't have to prove it's right...it just has to withstand attempts to disprove it. The anti-evolution camp has an unhill fight on its hands.
