QuestionsShould we have children?Having no descendants is the greatest failure of filial piety
Should we have children?Giving life is good

Having no descendants is the greatest failure of filial piety

"There are three unfilial acts, and the greatest is to have no posterity"; Shun married without telling his parents

Mencius c. 372 BC · c. 289 BCHuman nature is good: everyone carries the seed of benevolence.
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What it claims

One must found a family and have children, so that the line continues: it is a duty toward one's parents and ancestors.

Why

The family is a chain between ancestors and descendants: having no children breaks it.

The same idea through history
Confucius500 BCFor Confucius, filial piety does not end with the parents' death: they are served according to ritual while alive, buried according to ritual, then given offerings. The family thus links the living and the dead. He does not yet say that having no children is a fault.
Mencius320 BCMencius (c. 372-289 BC) lists having no descendants among three failures of filial piety and calls it the gravest. The idea is tied to ancestral offerings: without children, no one makes them any more.
Hans Jonas1979Different reason, different era: Jonas does not speak of filial piety but of responsibility toward future humans. Like Mencius, he thinks the continuity of generations is a duty, but he relates it to humanity as a whole, not to each person's lineage.
In short

"Having no descendants is the greatest failure of filial piety" is an argument by Mencius (Mencius 4A.26 (4th century BC), 320 BC) on the question "Should we have children?" (answer: giving life is good). Its claim: One must found a family and have children, so that the line continues: it is a duty toward one's parents and ancestors. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P3). AskPhilosophy presents 3 objections, 1 of them with a documented reply, and the original text behind each premise, checked word for word.

Mencius 4A.26 (4th century BC)
Valid with an implicit premise

In ancient China, the family is not only the people under one roof. It is a chain: ancestors, the living, children to come. Mencius says it in one sentence: there are three failures of filial piety, and the greatest is to have no descendants. He adds a striking example. The sage Shun married without telling his parents, against custom, so as not to risk staying childless. According to the commentator Zhao Qi (as rendered by Couvreur), the other two failures are letting one's parents do wrong without a word, and failing to earn enough to feed them; but that is a commentary, not Mencius' own text. Here the reason to have children is not the child's happiness: it is what one owes to one's parents and ancestors.

P1There are three failures of filial piety, and the gravest is to have no descendants.
P2This duty weighs so much that Shun, the model sage, agreed to marry without telling his parents rather than risk failing it. The wise judge that it was as if he had told them.
P3 · implicit premiseWhat filial piety requires, and ranks above even a rule of family etiquette, is a real duty: the family links the living to the ancestors and to future generations, and each person must hold their place in the chain.
Therefore one must found a family and have children, so that the line continues: it is a duty toward one's parents and ancestors.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P3, the computer finds a case where descendants are the greatest failure and Shun ranks them above etiquette, without it being a duty: for instance because it is only something highly desirable.
With P1, P2 and P3, the argument is valid. Without P3 it no longer is: one could think the greatest of the three failures remains a mere ideal or regret, not an obligation. Mencius does not write this, but Shun's example shows he treats it as an obligation that outranks other rules. Note that the argument concerns the son who owes his line descendants, not what the child to be born would gain.
Analogy. In a relay, each runner receives the baton and must pass it on. The one who stops does not just lose their own leg: they break the chain for the whole team, behind and ahead. Mencius sees the family this way.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Simone de Beauvoir 1949 · attacks the conclusion

Summary: in The Second Sex, Beauvoir argues that motherhood should be neither a destiny nor an obligation, but a free choice. A duty of lineage makes a child a debt to pay, and in practice it weighs mostly on women. For her, one is not less fulfilled without children.

no reply
see the argument
No reply possible: objection raised in 1949, after the author's death (-289).
Where the debate stands (our summary)Open point: we found no Confucian reply to Beauvoir. The core disagreement is about the nature of the duty: a debt to the lineage, or a project each person chooses freely.
David Benatar 2006 · attacks the conclusion

Summary: in Better Never to Have Been, Benatar defends an asymmetry. Pain is always bad even if no one feels it; the absence of pleasure is bad only if someone is there to be deprived of it. So for the one who is born, existing is a harm, while there is no harm in not being born. If this is true, the lineage cannot be a duty: it would impose a harm on a being who asked for nothing.

a defender replies
see the argument
No reply possible: objection raised in 2006, after the author's death (-289).
E
Elizabeth Harman defender of the argument · 2009
Summary: in her critical study of Benatar's book, Harman denies that coming into existence is a harm for someone whose life is worth living. She examines Benatar's asymmetry and sets against it the case of a life whose goods outweigh its ills.
Where the debate stands (our summary)Both camps agree on one point: if coming into existence were a harm, no lineage could be a duty. The core disagreement is about the asymmetry: is the lack of a good, when no one exists to regret it, neutral or bad?
L
Lu Xun 1919 · attacks premise 1

Lu Xun, a writer of the May Fourth Movement, attacks the old morality of filial piety: it puts the center on the side of the elders, when it should be on the side of the young, and turns toward the past what should look to the future. He does not deny that having no children is a misfortune: he only refuses to let it justify any means (he answers those who invoke Mencius' phrase to defend having several wives).

no reply
No reply possible: objection raised in 1919, after the author's death (-289).
Where the debate stands (our summary)Lu Xun keeps part of the thesis (continuing life is a goal) and rejects its orientation toward ancestors. Open point: modern Confucian defenders have not been collected here; the disagreement is about the direction of the duty (toward the past or toward the future).