This paper introduces the Monstrous Conclusion, according to which, for any population, there is a better population consisting of just one individual (the Monster). The Monstrous Conclusion is deeply counterintuitive. I defend a version of Prioritarianism as a particularly promising population axiology that does not imply the Monstrous Conclusion. According to this version of Prioritarianism, which I call Asymptotic Prioritarianism, there is diminishing marginal moral importance of individual welfare that can get close to, but never quite reach, some upper limit. I argue that Asymptotic Prioritarianism faces a theoretical cost, that I call the Absolute Priority Principle. However, the Absolute Priority Principle is an extreme version of what I call the Trade-off Condition, an already noteworthy problem facing other (more widely endorsed) versions of Prioritarianism. I conclude that it is better for a theory to imply the Absolute Priority Principle and avoid the Monstrous Conclusion than to imply the Monstrous Conclusion and the Trade-off Condition. The potential for Asymptotic Prioritarianism is substantial.

Plant ethics is a field of philosophy that discusses the moral value of plants, and individual responsibilities towards them. As anthropogenic climate change is likely to have devastating effects on plants, a plant ethics analysis of climate change is crucial to fully understand the extent of people’s responsibilities towards plants. However, surprisingly little has been written on this topic. This chapter aims to provide an overview of the main positions in plant ethics as well as an initial exploration of the following three salient questions concerning plant ethics and climate change. First: how stringent are people’s responsibilities to preserve plants? Second: do people have responsibilities to plant trees? Third: do people have responsibility to help plant migration? Plant ethics theories struggle to different extent with each of these questions. On all theories, people have great responsibilities to preserve, if not individual plants, at least large forests, and on most theories people have some responsibility to help plant migration. On whether there are responsibilities to plant trees, different plant ethics theories deliver widely different results, from there being no responsibility to plant any tree to there being responsibility to plant as many trees as possible. All three questions are venues for future research in plant ethics.

Population ethics is the branch of moral philosophy that studies how to compare scenarios in which the number, quality of life, and identity of the affected persons vary. By analysing paradoxes such as the Non-Identity Problem and the Repugnant Conclusion, it raises fundamental questions about the nature of value and our responsibilities toward future generations. This entry reconstructs the main theoretical debates, presents the most influential models, and assesses their strengths and limitations. It also shows how these discussions bear on practice in areas such as the ethics of procreation, intergenerational justice, climate policy, and the evaluation of emerging technologies.

This article assesses whether Law 40 of 2004, concerning “Norms on Medically Assisted Procreation,” has enhanced the quality of life of the Italian population from two perspectives. Firstly, it examines whether it has improved the quality of life for individuals whose existence is not contingent upon Law 40 (the “person affecting” perspective), as it satisfies the procreative desires of parents suffering from infertility and alleviates social issues for the entire population. Secondly, it investigates whether it enhances the average and total quality of life of the Italian population (an impersonal perspective). However, it is noted that funding a structured immigration plan would be a more effective means of addressing the aforementioned social issues, and that restricting access to assisted reproduction to only heterosexual couples is morally unjustifiable.

How much should we do to fight climate change? I argue that institutions ought to impose heavy burdens upon their members to fight climate change. In fact, I argue that an institution ought to impose a burden on its members if this prevents them from causing a greater burden to at least as many people. I show that, in the case of climate change, this means that an institution ought to demand from its members everything that is not an inviolable aspect of individuals’ lives. This conclusion remains true even if individual emissions do not make a difference with respect to the effects of climate change. In fact, surprisingly, it is often the case that the less impact individuals can have on climate change, the more an institution ought to impose a burden on them.

Secondo una tradizione di filosofi, qui chiamati Pessimisti, la vita non è mai degna di essere vissuta, nemmeno in linea di principio. Al contrario, una tradizione qui chiamata Ottimista ritiene che la vita sia sempre, in linea di principio, degna di essere vissuta. In questo testo si mostra che entrambe le posizioni hanno conseguenze teoriche contro-intuitive che non sono state finora notate. Nello specifico, il Pessimismo viola la transitività della proprietà “più valore di” (spiegata nel testo), mentre l’Ottimismo implica che una lunga vita di sofferenze sia meglio di una vita di gioie che sia relativamente più breve. Inoltre, entrambe le posizioni danno raccomandazioni implausibili nella scelta tra alcune lotterie. Infine, le pretese dei Pessimisti di avere prove empiriche della correttezza della loro posizione e di poter risolvere i problemi di etica delle generazioni future non sono fondate. Si conclude che, a priori, la vita può essere o degna di essere vissuta o degna di non essere vissuta.

Qual è la dimensione ottimale della popolazione umana nel 2050? Si possono ordinare le popolazioni, dalla migliore alla peggiore, considerando la qualità della vita media e totale degli individui e il loro livello di eguaglianza. I dati suggeriscono che l’umanità, a prescindere dalla sua dimensione, può avere una popolazione migliore nel 2050 rispetto al 2020 solo qualora la crisi climatica si risolva positivamente. Se l’azione a favore del clima fallisce, la dimensione della popolazione non deve superare eccessivamente gli 8 miliardi.

Parfit underlines how, in Different Number Choices, it is doubtful whether someone ought to cause a higher average or a higher total of good. Assuming Parfit’s theory of Personal Identity I argue that personal choices such as choosing between possible careers determine the chooser’s future identity: such choices are thus Same Number Choices. Since personal choices can influence a life’s length and enjoyed wellbeing, Same Number Choices share with Different Number Choices the dilemma of choosing between higher average and higher total of good. In the final part of the paper I support the principle of total good by suggesting that the crucial objection against it, called Quality Condition, seems to be valid only for populations too big to be correctly compared and violates a rule that seems obvious in small populations. The equivalent of the Quality Condition in Same Number Choices seems to be valid only for amounts of times too big to be correctly compared and violates an obvious prudential rule in short times.