If I'm understanding you correctly, you're saying that evolution is a tautological collapse of the "why" in "why do we exist".
Let me explain: evolution is a massive, groping search in the ultrahigh dimensional space of possible organisms, one that is solving for fitness by literally obliterating less fit entities from existence. So fitness is actually just "what is good at existing", which, given enough iterations, will determine what actually exists anyway.
So now we can simply substitute in the answer to the question "why do we exist?": We exist because we evolved, which is like saying, we exist because we are fit, which is like saying, we exist because we exist. And that explanational ouroboros sort of levitates before us, a silent, immutable feature of the universe: we are here because we exist, because we exist, because...
And it's so easy for us to make that small, seductive step to saying that our existence is therefore inevitable. But I think that's a mistake. The tautology doesn't answer the why question; it annihilates it, dissolving the teleological question into its mechanistic refutation: WE. ARE. HERE.
It's not a search. There is no goal, no searcher, and nothing to find. The word evolution was chosen deliberately in its meaning of a dynamical system moving through state space. Not searching: just evolving.
In a banal sense, it's correct to say that there's no searcher, no goal to evolution. As far as we know, "natural selection" isn't "real" in the sense that electromagnetism is "real"; natural selection is just a staggeringly convenient shorthand that refers to the multitude of ways organisms can die. But if we go further, and think of evolution as a mere random walk through state space, we've suddenly lost all explanatory power. The independent emergence of echolocation in whales and bats, for instance, becomes a brute mystery.
Evolution only makes sense if we think of it as as some kind of massively parallel Monte Carlo that's weighted to explore regions of the state space with high fitness. So it's perfectly valid to talk, as biologist do, of selection pressures and directional selection, because- and here we've come full circle- there is a goal to evolution: to exist.
And, to exist with a minimum of fuss. Why do people get cancer, or get feeble when old? Well, if the organism can reproduce and support their offspring well enough, given the eco-niche and available calories etc, then they are Fit. So, just enough avoiding cancer to work out in the end.
Kind of like the space program, where everything is made by the lowest bidder.
While Evolution clearly doesn't have any "goal" I wonder if we can say that it directs to the goal that is constantly changing (that is, a goal only known once some organism is there)?
Let me explain: evolution is a massive, groping search in the ultrahigh dimensional space of possible organisms, one that is solving for fitness by literally obliterating less fit entities from existence. So fitness is actually just "what is good at existing", which, given enough iterations, will determine what actually exists anyway.
So now we can simply substitute in the answer to the question "why do we exist?": We exist because we evolved, which is like saying, we exist because we are fit, which is like saying, we exist because we exist. And that explanational ouroboros sort of levitates before us, a silent, immutable feature of the universe: we are here because we exist, because we exist, because...
And it's so easy for us to make that small, seductive step to saying that our existence is therefore inevitable. But I think that's a mistake. The tautology doesn't answer the why question; it annihilates it, dissolving the teleological question into its mechanistic refutation: WE. ARE. HERE.