These lines sound really spot-on, don’t they? Tough to argue with lines as forceful and neat as these are. Plus the idea is cool: the poet can grant immortality. But it’s crucial that we treat these lines critically and not just accept them as drops of Shakespearean life-wisdom. First of all, how come he assumes that as long as men breathe or eyes can see (note the "or" – what if eyes could see but men couldn’t breathe?), this poem will continue to be read? We do still read it, but there’s no guarantee that people will keep reading these sonnets, and once they stop, the beloved would cease to exist. It seems like his or her immortality is pretty tenuous. Plus, we’ve got to wonder what kind of "life" he thinks the beloved will have. He or she certainly won’t be conscious, and will only be recognized as how the poet describes him or her. All we’ve got to go there is "more lovely and more temperate" than the summer. If that’s all the beloved reduces to, it’s really not much of a life.