It seems to me that the following quote from Hume is also relevant: “Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not conclusions of our reason” (“A Treatise of Human Nature”, 1739, III, I, i).

That doesn't mean that our moral sense is purely a product of genetic evolution. Hayek provided a sensible explanation of the evolution of rules of conduct evolving because the groups who practiced them flourished and displaced other groups.

2. Only from a species perspective (if a species can have one) is the individual's purpose to make copies of its genes. Unless the individual is concerned about what happens after its death, whether it made copies of its genes or not is utterly irrelevant to it.

3. The quest for meaning is not universal among humans. E.g., in Christian cosmology the universe is imbued with God's Will and Purpose with which we must be in accord, and from which we draw our meaning. Or more strictly, the possibility of “the meaning of life” is implicit in God's hidden purpose. In Hindu/Buddhist cosmology, the universe has no purpose. (e.g., see Myths and Symbols in Indian Art and Civilization, H. Zimmer); the God/gods/no-god has no purpose and consequently, as parts of a purposeless universe, we have no objective context in which to talk about our own purpose. That does not prevent Hindus or Buddhists from talking about the proper way to lead life.

I suggest therefore that this quest for meaning (“why are we here?”) is culture-specific. Moreover, the author is correct that the question has no bearing on how to live life. This is an empirical fact (i.e., one can arrive at it by examining world cultures) and not a philosophical one.

I further suggest that the quest for the meaning of life is a hangover from Christianity. Part of the conflict between religion and science in the west is precisely because science says that “why are we here?” is an ill-posed question.

5. People who have absorbed this search for meaning find paradoxes like Tunku Varadarajan did:

http://www.nytimes.com/2008/10/29/opinion/29var…

You mean we haven't been designed to kill kittens? Oh dear…

I think this is because you aren't looking at the question with sufficient granularity. If by 'why' you mean 'how' then, yes, the most general answer is because ma and pa had the sex, and then you could break down the hows of sex into as much information as you want (from the nervous system, to perceptual stimulus, to physiology, to hormones, to the base pair sequence that coded those hormones). At this most general level you are right that this doesn't give you much useful information. This could be telling you to go have sex with a woman, or reproduce, or reproduce with your mother — none of which seem like they would be better choices than what your natural wants and not-wants could guide better (people already know they want to have sex, and in the case of gay or asexual people, who don't instinctively desire reproductive sex, the guideline would make their lives worse).

But at a deeper level of 'how' I think knowing all of your genes, and how they will react and have reacted in the past would be about the most useful information you could ever have about what decisions to make in your life. To use your own nerdy example, let's say bizarro world Will spends 10 years at kitten-eating school, and then another 5 years in the kitten-eating labor force before having a nervous breakdown and joining a PETA monastery where he can spend the rest of his life doing what he now realizes he wanted to do all along: pet kittens.

But with the correct amount of biological self-knowledge, Will could have saved himself 15 traumatic, wasted years and a nervous breakdown. He would have known beforehand that kitten-eating would upset him and why. With full genetic self-knowledge people could plan their lives for the maximum experience of “meaning” at the earliest possible age.(starting with their parents)

To a rough extent this already happens with our limited knowledge. People are similar enough that we can see things like money, accomplishment, deeper relationships, children, community, and religion, generally lead to more meaningful lives (children appear to be the only general false positive). So most people lay some sort of early groundwork to make one or more of these things happen.