Evolution is not true. It's not false either and any discussion about it being that is missing the point.
Evolution is the best model we have to explain how life and species interact and evolve.
I think you mean that the "theory of evolution via natural selection" is the best model we have to explain the observed phenomena of evolution. Analogous to the Newtownian theory of gravity explaining the mechanics of observed terrestrial and celestial gravity. Gravity and evolution are simply there, how they occur requires a theoretical explanation.
The "theory of evolution via natural selection" is itself another (very common) misconception about evolution. Don't equate evolution with natural selection; they are far from synonymous. In fact, we have good reason to think that most evolution is non-adaptive.
I wouldn't say it's observed; no one has observed billions of years of evolution. That's why there is debate. Please don't compare to the observation of gravity; it's not even comparable.
How so? Evolution is just change in populations over time with common descent, and that's pretty well demonstrated through the things I mentioned, about the same as gravity is demonstrated by things falling. What's different?
I've never seen it demonstrated definitively through the fossil record. There are a lot of assumptions and best-guesses leading back to common ancestors.
I've never seen gravity demonstrated definitively either. Sure, they say that there's this force that makes stuff fall, but I've seen plenty of things go up instead of down when released.
That is farcical. If something is thrown in the air, you can demonstrate the force of Newton's constant, thereby definitively demonstrating gravity. Actually calculating the gravitational constant with precision is the only difficulty there. Nothing about this is assumed. Which back to the point, is nothing like the assumptions of hereditary lines in the so-called "fossil record".
Gravity is a force you can measure, make experiments with and validate.
You can use the scientific method to invalidate gravity. You can't do that with evolution and therefore you can't compare the theory of gravity with the theory of evolution the way I see it.
It is not (self evidently) true that evolution correctly models the origin of adaptations.[1] That is, the menu-creation ex ante selection is a "black box" model, and that is at best problematic, from a logical/mathematical/and "scientific" perspective. The randomness hypothesis is almost surely wrong here (as the mechanism of menu selction).
Most often the discussion is about whether evolution is true or not.
Evolution is not true. It's not false either and any discussion about it being that is missing the point.
Evolution is the best model we have to explain how life and species interact and evolve.
There are no finite answers in evolution, only observations of phenomena. But those observations best describe the biological world.