". . . the question of pain aside, the atheist has no fear of death; he is incessantly ready to die, having no need, in the face of the void, of putting his affairs in order.
"But though an atheist, he is no less a man, and has [therefore] feelings of affection for other beings who are ordinarily not themselves atheists, and do not look upon death with the same indifference. [So] here again the [unfounded] moral conscience prevents the atheist from acting in rigorous accord with his atheism. He doesn’t need to put his affairs in order, but he may have to concern himself with the affairs of those of his neighbors to whom he is useful, and who might suffer from his death, [whether] in their feelings or in their interests."
The biologist and philosopher of science Félix Alexandre Le Dantec (1869-1917), L’athéisme (Paris: Flammarion, 1907), 101, 106, translation mine. I was put onto this by Rémi Brague, Moderately modern, trans. Paul Seaton (South Bend, IN: St. Augustine’s Press, 2019), 83, and have read no more than the sections inclusive of these excerpts. Le Dantec is speaking not of (say) "those braggarts of anticlericalism [(ces fanfarons de l’anticléricalisme)]" who enjoy "astonishing their contemporaries with the spectacle of their bravery" (102), but only of the extremely rare "true" or "perfect atheist," for every one of which life must be necessarily an insufferable burden:
I must here affirm in all sincerity that I see no chain of reasoning capable of preventing the perfect atheist from committing suicide [(je vois aucun raisonnement capable d’arrêter l’athée parfait que le suicide tente)]. Only, there is no [truly] perfect atheist. The [unfounded] moral conscience imposes on the most liberated of atheists obligations that he cannot avoid. The atheist who is a son, a brother, a husband is held back, in the absence of [a] valid chain of reasoning, by a care for the grief he would cause, and for the need that those dear to him have of him. An atheist capable of renouncing his obligations to the world, as monks do, would commit suicide without delay [(100-101)].