Regret said:
Now, I feel that there is absolutely no purpose for anything that occurs anywhere in the universe (or, indeed, in others). I could take a gun and kill anyone I damned well please and, for all intents and purposes, it wouldn't make a blind bit of difference. I could discover the cure for cancer, but what good would that do? Everything is going to die eventually.
Sounds like you, my friend, are having an existentialist crisis. Of course, this is opinionated, but technically, nihilism has sound factual basis. From a purely detached perspective, of course, the universe does not care whether you run down that orphaned boy, however, being on par in regards to sentience with all other human beings, one could say that 'meaning' as such, is conferred upon you by the collective, if not yourself.
As such either their morals can apply to you, their morals being the sum of the communal whole, meaning that such an act would indeed be immoral and wrong. Conversely, you can be led by your own self, and take what some deem an amoral standpoint, this is superior in my opinion. Therefore the inherent 'meaning' of life is to enjoy yourself, live life to the fullest, 'carpe diem', etc etc. Depending on your level of empathy this urge can extend to catering for others needs. As you said, you could discover the cure for cancer. Perhaps, in the long run, if say the sun collides with earth, destroying humanity, at least the people cured will live longer and more fulfilling lives, as you would wish for yourself. Also, another possibility is that one of those people cured may be able to avert certain disasters for more individuals in future, perpetuating your kindness and overall improving the human race.
Many retort to this claim by stating, 'why would i care about the people in 100 years, i wont even be around?' A perfectly valid point, as is anything in a philosophical discussion. I believe that when one cannot remain as a conscious and sentient being, the 'next best thing' as it were, is to facilitate the enjoyment of life for others in future. Whilst i maintain the belief that consciousness descends into oblivion upon death, the burden of your posterity and inheritance still weighs heavily upon one's consciousness during life. Therefore, this caring and moral system is merely one more step into making the most out of your one, short, life.
Also, thank you for the interesting topic OP. It's great to see some truly philosophical stuff floating around. I mean, it got me thinking at 2 am in the morning, now that is impressive.