I often hear some people say that life is essentially full of meaning. Therefore, they almost always go on to insist, we should give life a meaning.
There was a man, named Tolstoy, who was once in such a depressive state that he found possibly no meaning in life, because he unfortunately realized that everything he would do would cease to exist. After all, the world will eventually come to an end.
Philosophers can respond to this evaluation of life in various ways. Simple one is to try to refute it. The entry linked below is an introduction of such an attempt.
But there may well be other ways. One of my favorites is to countenance the conclusion that life can lack any meaning whatsoever, but to deny that the meaninglessness is a problem. Life has no meaning, yes. But there is no problem about it, nor is there any need to worry about it. Those who take this way of response argue that we are the only creature that can ask whether life bears any meaning or not, and that we have to look on the fact as important. Even if we are preoccupied with what we find worth doing, once in a while we tend to be aware of the possility of its worthlessness. This awareness feels sincerely sad, but it is an ideal way of living.
In this book, you can find more detalis about the latter response against the argument about the insignificance of life. The book is about meaning in broader sense.