You refuse to give a simple yes/no answer to:
One is the emergence of the brain through darwinian evolution. One brain that is capable or reasoning.
The other thing is the quest for truth. Using that brain for discovering the world and making truth assessments of it.
The former has to do with the process of darwinian evolution. The latter not, it uses a mechanism produced by evolution, but is not part of the evolutionary process (unless you think you can modify your DNA by thinking). Agreed?"
Something that I thought respectfully represents your worldview.
So I have to explain why statements like this one is a problem. The reply is written as directly addressing Sebastian, but it could be read in general terms:
When you say truth, you probably mean absolute truth. In my mind there is no such concept. In yours there may very well be such a concept.
If I answer yes, you immediately jump to "Oh so you can know [absolute] truth? How is that possible considering an adapted mind?". You may not state it, but the absolute is present in your mental model of the concept.
It isn't possible to know absolute truth. The phaneron represents the limits of our understanding. It brings into question truths we know.
Do you see how your implied assumptions about how the world works can make you fail completely to understand, and how me answering your question can satisfy us both, because you think I enforced your view, but in fact we mean different things when we say the same things.
Markus keeps talking about the universe being an "accident". I tried to explain early on in the post that the terminology does not make sense. His assumption that there is agency makes him conclude that without it everything must be an accident, but an accident implies an intended outcome, and an accidental one. If a droplet falls on a leaf, is it an accident? Nope. You require an agent for an accident to occur at all.
So from a strictly naturalistic point of view nature does not deal in accidents, nature just is. Carl Sagan described nature as being indifferent. Granted that still appeals to some sort of agency (probably only for the sake of explanation), but it gets the point across that nature has no intended purpose or outcome.
Even if accident is meant in a kinder way consider this: If I get black jack five times in a row, we call it blind luck. If an unintended outcome is good, we call it luck, not accident. Even though I still disagree with the use of the term luck, it removes agency and acknowledges that what has happened is good.
But is it good? Nope. It just is. Nature is what it is, no matter what we think it is. We are often wrong about it too and nature kicks our asses for being wrong. In the middle ages people thought that the plague was the wrath of god, all their piety and dedication didn't make the plague go away. They were wrong, or should I say, us, humanity, was wrong.
You will never be able to understand a strictly materialistic view of the world if you cannot flip your perspective around and imagine that the first premise of existence according to you, namely that there is a god, is false or at least not self evident.
Many, if not all theistic arguments suffer from having this premise, either explicitly with presuppositional apologetics, or implied with other types.
In that sense, the philosophical concept that you are trying to use against naturalism, namely that a first premise may be false and make all consequent conclusions false actually applies to the theistic view too.
What is in favour of the non-theistic view is that we can derive new laws of nature from non-theistic methods, whereas theological methods have no useful output. In that sense the naturalistic view vindicates itself by being valuable, and the theistic view is left destitute.
 I realise that the argument is a little different, and mixes in evolution, but it is almost identical to this description.