Some critics of the pessimist often think they have his back to the wall when they blithely jeer, “If this is how this fellow feels, he should either kill himself or be decried as a hypocrite.” That the pessimist should kill himself in order to live up to his ideas may be counterattacked as betraying such a crass intellect that it does not deserve a response. Yet it is not much of a chore to produce one. Simply because someone has reached the conclusion that the amount of suffering in this world is enough that anyone would be better off not having been born does not mean that by force of logic or sincerity he must kill himself. It only means he has concluded that the amount of suffering in this world is enough that anyone would be better off never having been born. Others may disagree on this point as it pleases them, but they must accept that if they believe themselves to have a stronger case than the pessimist, then they are mistaken.I'm currently reading The Conspiracy Against the Human Race by short story horror writer Thomas Ligotti (I say "short story" because that's the form he mostly writes in). Conspiracy is his only book-length work of non-fiction so far, and I highly recommend it, especially for those of you who are of a pessimistic frame of mind. But does being a pessimist (the correct view of the human condition in my opinion) and believing life is full of unwanted horrors and is harmful (thus leading to the position of "antinatalism", that is, being against bringing new humans into the world) require one to kill oneself in order to be consistent? Well, the answer is not only no, but hell no!
Naturally, there are pessimists who do kill themselves, but nothing obliges them to kill themselves or live with the mark of the hypocrite on their brow.-Thomas Ligotti, The Conspiracy Against the Human Race
Obviously a pessimist who does commit suicide is not being inconsistent in any way either, for some may overcome the instinct of self-preservation and be so overwhelmed with sorrow, despair, depression or physical pain that they are driven to end their lives. But most of us, pessimists or "optimists", have interests that keep us alive, and they are usually of sufficient worthiness for us to continue to live. One can even say that precisely because the pessimist sees the harm in life, he is against imposing that harm on others and so is against procreation, but is also aware that once someone is here, including himself, continuing life may be the least harmful course of action.
If one of the things that makes life bad is our inevitable death, then our own death is bad as well, and the truly hypocritical position would be to end our life unless the things that make life not worthwhile become so strong as to overwhelm whatever worthwhile things we find in our life. And therefore we should not, under normal circumstances, kill ourselves, both for our own sake and for that of our loved ones, upon whom the suicide of someone they love and care about can be extremely devastating, making their lives much worse.
So, while we don't want to force life and its harms on someone else by having children, including the horrible harm of eventual death that every human must face, it may be that the least harm we can do to ourselves and others is to live.