The Asymmetry Argument, most notably articulated by philosopher David Benatar in his 2006 book Better Never to Have Been: The Harm of Coming into Existence, posits a fundamental imbalance between the value of pleasure and pain in considering whether or not to bring a new person into existence. The argument doesn't focus on whether existing lives are worth continuing, but rather on whether new lives should be started.
Benatar argues that while the presence of pain is bad and the presence of pleasure is good, the absence of pain is good even if no one experiences it, whereas the absence of pleasure is not bad unless someone exists to be deprived of it. In other words, not bringing someone into existence avoids potential suffering, which is a good thing, but it doesn't deprive anyone of potential happiness, which is not a bad thing. This leads to the conclusion that bringing someone into existence always constitutes a net harm to that person, as existence inevitably involves some suffering.
This argument supports antinatalism, the view that procreation is morally wrong. Benatar's asymmetry suggests that the ethical choice leans towards non-procreation. While many find this view controversial, it has spurred considerable debate and philosophical analysis. Critics have questioned the validity of the asymmetry and whether it truly leads to the conclusion that it is always better never to have existed. Some argue that the absence of pain is only impersonally good, not personally good, since there is no person to experience its absence. Fumitake Yoshizawa argued in a 2021 paper that Benatar's conclusion doesn't follow even if his premises are granted.
