"Why not?" is not an answer to "Why?"
2. we like to understand things, for the sake of understanding them.
3. we like to understand things in order to come up with technical solutions to problems which make life less pleasant than it could be.
Both 2. and 3. are related to improving our condition. What is the evolutionary mechanism at play? Survival? Probably. If so, then when we embrace the goals of 2. and 3., we are assigning a purpose to the process of evolution that is illusionary. There is no purpose.
4. Understanding how the mechanisms of life work might just possibly teach us how the mechanisms of death work, and allow us to switch off those genetic factors leading to decrepitude and death.
Why is immortality preferrable to non-existence? What does it accomplish? According to natural selection, creatures have a survival instinct because those without one died off. Again, that is a process. To seek immortality as something desirable is to mistaken the process for a purpose. A fly may flee your swatter without knowing why. (All the flys that didn't have the flee function are flat). But we as humans know better. The jig is up. We seek to improve our condition because our mutation led to a survival instinct while someone else's did not. Now that we know, how do we pretend it is anything else? Why do we?
all, from a life-is-all-there-is, perfectly sound reasons based entirely on natural self-interest.
happy, now?
I was already happy.
why not IS an answer to why. just because you don't like it does not make it any less a common motive for human behavior.
You make a very serious basic error - you assume humans are largely rational. We are not. Your solipsism/existentialism argument would apply IFF humans were entirely rational. We are not, not even close, so your argument fails.
Whether or not there is a larger purpose to being alive than simply being alive, we have an innate tendency to value our own lives and a desire to establish patterns on the world around us that please us at least temporarily.
Basically, your nonsense is the equivalent of saying "Why rearrange your furniture, why vacuum? You'll just rearrange it again sooner or later, and the dirt will always come back"
so? so what?
Most of us LIKE a clean house, and prefer to have furniture arranged in a manner pleasing to uis at the time in question. What has passed and what is to come are irrelevant to the matter at hand.