Leading a human life is a full-time occupation, to which everyone devotes decades of intense concern. - Thomas Nagel

The problem is one of opposition between subjective and objective points of view. There is a tendency to seek an objective account of everything before admitting its reality. But often what appears to a more subjective point of view cannot be accounted for in this way. So either the objective conception of the world is incomplete, or the subjective involves illusions that should be rejected.

Ethics increases the range of what it is about ourselves that we can will—extending it from our actions to the motives and character traits and dispositions from which they arise. We want to be able to will the sources of our actions down to the very bottom.

That is what is meant, I think by the allegation that it is good simply to be alive, even if one is undergoing terrible experiences. The situation is roughly this: There are elements which, if added to one's experience, make life better; there are other elements which, if added to one's experience, make life worse. But what remains when these are set aside is not merely neutral: it is emphatically positive. Therefore life is worth living even when the bad elements of experience are plentiful, and the good ones too meager to outweigh the bad ones on their own. The additional positive weight is supplied by experience itself, rather than by any of its contents.