How might a person who does not subscribe to any organized religion and does not
Good question(s)! I suggest the idea of a person living on in the memories of others is somewhat problematic, especially given that (assuming you are correct) death involves a person ceasing to be. But it may be that your life still has meaning in at least two ways: while you would not live on in others' memories, the significance of your life and the values you had might well live on with others. Of course if modern astronomy is correct all life on earth will end in about 4 billion years, so this bit about living on indefinitely will be a bit tricky. A second way to approach your question would be to refer to the point of view of the universe or the point of view of some ideal observer. This is also a little problematic, however, as it seems that the universe cannot (literally) have a point of view and if the ideal observer is merely hypothetical (viz. there is no God) and so this might also be a difficult foundation to secure meaning. Perhaps thre is a third option: four dimensionalism. According to this account, all moments are equally real. On one version it will always be the case the you are having a meaningful life in 2010. The wikipedia entry for 'four dimensionalism' is reliable, so check that out as a third option. Of course you might also take another look at the prospects of the soul in a theistic framework, but that can be the subject of another exchange.