Future Generations Problem

1. Introduction

The Future Generations Problem concerns how to understand our moral duties to people who do not yet exist, especially when our present actions help determine who will exist in the future. It sits at the intersection of population ethics, intergenerational justice, and applied ethics in areas such as climate policy, technological development, and bioethics.

At a basic level, many ethical and political theories assume that wrongdoing involves making particular individuals worse off than they otherwise would have been. Yet many choices with long-term consequences—such as adopting a high‑emissions development path or designing long-lived institutions—change patterns of reproduction, migration, and social life. As a result, they influence which particular people come to exist. This creates a puzzle: if alternative choices would have led to different future individuals altogether, then no specific future person seems harmed, even when future conditions appear unjust or grim.

This tension is sharpened in Derek Parfit’s formulation of the Non-Identity Problem, which has become a central version of the Future Generations Problem. Parfit’s work suggests that standard person-focused moral principles struggle to capture why some large‑scale, future‑shaping decisions seem objectionable. In response, philosophers have explored both revisions of person-centred ethics and more impersonal approaches that evaluate states of affairs by overall features such as total welfare, justice, or capabilities.

The Future Generations Problem has become influential beyond moral philosophy. It has informed debates about discounting in economics, the design of constitutions and legal rights for future citizens, and the analysis of existential risk and longtermism. Despite substantial work, there remains no consensus on how to reconcile our intuitions about duties to future people with the metaphysical and causal facts about their existence and identity.

2. Origin and Attribution

The contemporary formulation of the Future Generations Problem is most closely associated with Derek Parfit, whose Reasons and Persons (1984) articulated the Non-Identity Problem and a range of population-ethical puzzles. Parfit’s arguments are widely regarded as having crystallised and systematised concerns that had been emerging in legal, political, and environmental theory.

Principal attributions

Parfit is commonly credited with giving the problem its now standard identity-related structure, in which different policies lead to different future people. However, some scholars argue that intergenerational justice debates in law and political theory, especially the work of Edith Brown Weiss, independently developed related themes of obligations to “future generations” as a collective.

There is also discussion about antecedents. Postwar environmental ethics and nuclear ethics raised questions about long-lived harms and collective responsibility, and some argue that these discourses already contained the core idea that present actions can constrain or jeopardise the prospects of distant future people. Others trace partial precursors to earlier thinkers such as Hans Jonas (The Imperative of Responsibility, 1979) and to demographic and overpopulation debates in the 1960s and 1970s.

Nevertheless, the label “Non-Identity Problem” and its now familiar structure—identity-affecting actions combined with person-affecting morality—are generally attributed to Parfit, with later elaborations and critiques by figures including David Heyd, Jeff McMahan, Elizabeth Harman, and Larry Temkin.

3. Historical Context and Early Discussions

The Future Generations Problem developed within a broader mid‑ to late‑20th‑century context marked by environmental anxiety, nuclear peril, and debates over development and population growth. Philosophical reflection on duties to the future interacted closely with these political and scientific concerns.

Key contextual developments

Early philosophical treatments often did not yet emphasise identity-related puzzles. John Rawls in A Theory of Justice (1971) discussed a “just savings principle,” which asks how much each generation should save for later ones, treating generations somewhat analogously to contemporaneous parties in the original position. Brian Barry and others developed notions of justice between generations, focusing on resource distribution and institutional design.

In legal and policy circles, Edith Brown Weiss argued for principles of “planetary trust” and intergenerational equity, proposing that each generation holds the earth in trust for both present and future people. Nuclear ethics, especially concerns about radioactive waste storage and testing, prompted questions about the rights of people who would be affected centuries later.

Only gradually did philosophers begin to notice that many of these long‑term decisions are identity‑affecting. Earlier discussions often assumed a relatively fixed set of future persons whose interests must be weighed. The later recognition that policies shape who comes to exist introduced new layers of complexity and motivated the more technically developed population-ethical work of the 1970s and 1980s, culminating in Parfit’s influential formulation.

4. Formulating the Future Generations Problem

Philosophers typically formulate the Future Generations Problem as a set of tensions among three elements: (1) common moral intuitions about duties to future people, (2) metaphysical and causal claims about how future persons come to exist, and (3) background commitments of ethical theories.

Core components of the formulation

1. Temporal distance: Future people may live decades, centuries, or millennia from now. This raises issues about how to weigh their interests relative to present people, and whether temporal distance has any moral relevance.

2. Dependence of existence on present actions: Many large-scale decisions—about energy infrastructure, economic policy, reproductive technologies, or migration—are identity‑affecting. Different choices today would lead to different patterns of conception and thus different future individuals.

3. Life worth living: In standard cases, the future people who result from our actions have lives that appear, overall, worth living, even if they face serious burdens such as environmental degradation or institutional injustice.

4. Intuitive wrongness of certain policies: Many policies that impose foreseeable and avoidable risks or hardships on distant future populations are widely judged morally objectionable, even if these policies are accompanied by benefits to present people.

5. Person-affecting starting point: A widely held starting point is that wronging someone involves making that particular person worse off than they otherwise would have been.

The problem arises when these elements are combined. If different policies lead to different people existing, and if each actual future person has a life worth living, then it can be difficult—on a strictly person-affecting understanding—to identify any specific harmed individual. Yet the policies can still seem unjust or reckless toward “future generations.”

Formulations differ in focus. Some emphasise harm and wronging of individuals; others stress fairness between generations or the value of future states of affairs. But they converge on the idea that our standard ethical tools struggle to capture what seems troubling about sacrificing long‑term future people for short‑term gain.

5. The Non-Identity Problem and Identity-Affecting Actions

The Non-Identity Problem is a specific and influential version of the Future Generations Problem. It arises in cases where:

• present choices determine which particular people will exist later; and
• those people’s lives are, overall, worth living, even if burdened.

Identity-affecting actions

Identity‑affecting actions are actions that change which specific individuals come into existence, often by altering timing or circumstances of conception. Examples used in the literature include:

• A government’s choice of long-term energy policy, which influences economic conditions, migration, and family decisions.
• A couple’s decision to conceive a child now under risky conditions versus later under safer conditions.
• The adoption of new reproductive technologies that allow or prevent the birth of particular individuals.

In such cases, had a different choice been made, the numerically same future person would not have existed at all; a different person would have occupied that future role.

Structure of the Non-Identity Problem

Parfit’s canonical examples—such as the “14‑year‑old girl” choosing to have a child now versus later, or societies that adopt different development paths—highlight the following structure:

1. An action will cause some future person to exist in a certain condition (e.g., with a disability or in a degraded environment).
2. If the action were not taken, that particular person would not exist at all.
3. The person’s life, though burdened, is still judged worth living.
4. Intuitively, the action seems morally wrong or at least morally questionable.
5. But on a simple comparative harm view (worse-off relative to a relevant alternative), the person has not been harmed, since their only alternative was non-existence.

This yields a puzzle: can we say that anyone has been wronged, and if not, how can we explain the apparent wrongness?

Different theorists emphasise different implications. Some treat identity-affecting facts as undermining attributions of harm, suggesting no special problem remains. Others see them as motivating shifts to impersonal standards, or to non-comparative accounts of harm and wronging that do not rely on a better alternative for the same individual.

6. Logical Structure and Core Premises

Many philosophers reconstruct the Future Generations Problem, especially in its Non-Identity form, as a reductio-style argument showing a tension among plausible premises. Different reconstructions vary in detail, but they typically share several core premises.

Typical core premises

From P1–P4, it appears to follow that no particular future person is harmed in identity‑affecting cases, since the alternative is non-existence. Combined with P5, this yields an apparent inconsistency: our person‑affecting framework seems unable to vindicate our judgments about wronging future generations.

Variants in logical framing

Different authors adjust these premises:

• Some weaken P1 to allow that outcomes can be impersonally better or worse, but maintain that wronging is person-affecting.
• Others question P4 by adopting non-comparative accounts of harm, on which subjecting someone to a seriously deficient condition can count as harm regardless of alternatives.
• Still others challenge P5, arguing that intuitions about wrongness in some Non-Identity cases may be unreliable.

Formally, the problem may be represented as a set of pairwise incompatible claims, where any attempt to resolve the puzzle involves rejecting or revising at least one:

1. Strictly person-affecting wrongness.
2. Identity-affecting causal structure in many future-oriented decisions.
3. The intuition that some such decisions are morally wrong despite not making any specific person worse off.

The ongoing debate largely concerns which of these elements should be modified and how.

7. Person-Affecting vs Impersonal Moral Theories

A central axis in responses to the Future Generations Problem contrasts person‑affecting and impersonal moral theories.

Person-affecting views

Person-affecting (or person-centred) views hold, in some form, that:

• moral evaluation of outcomes crucially depends on how they affect particular individuals; and
• creating new people is morally neutral or optional provided their lives are worth living, since there is no existing person for whom non‑creation is worse.

Advocates argue that this fits everyday moral thinking, where harming or benefiting someone presupposes that person’s existence. In population ethics, person-affecting ideas are developed by philosophers such as Jan Narveson and David Heyd, often to resist strong duties to bring additional happy people into existence.

Impersonal theories

Impersonal theories, especially forms of consequentialism, evaluate states of affairs by overall properties—such as total welfare, average welfare, or the distribution of well‑being—without requiring that every difference correspond to a change for some already‑identifiable person.

Examples include:

• Total utilitarianism, which ranks outcomes by the sum of well-being over all who exist.
• Average utilitarianism, which focuses on mean well-being.
• Other population-ethical rules that treat “how many and how well” as jointly relevant.

From an impersonal standpoint, outcomes with better overall features can be morally preferred even if they involve different sets of individuals.

Tensions and trade-offs

The Future Generations Problem highlights trade-offs between these approaches:

The Future Generations Problem thus serves as a testing ground for person-affecting versus impersonal commitments, with different theorists prioritising intuitive fit about harm, avoidance of paradoxes, or the ability to condemn apparently reckless long-term policies.

8. Policy Examples: Climate Change and Environmental Degradation

Discussions of the Future Generations Problem frequently use climate change and environmental degradation to illustrate how identity-affecting facts interact with long-term policy choices.

Climate policy scenarios

Consider a choice between:

• a high‑emissions, high‑growth pathway that yields substantial present benefits but leads to severe climate impacts after 2100; and
• a low‑emissions, sustainable pathway involving present sacrifices but gentler long‑term impacts.

Because economic structures, migration patterns, and social norms differ between these paths, they would lead to different people being conceived at different times. Thus, the individuals who experience late‑century climate impacts under the high‑emissions scenario typically owe their very existence to that scenario.

This raises a puzzle: if these individuals’ lives are still worth living, can they claim to have been harmed relative to any feasible alternative? Many argue that it nevertheless seems wrong to choose policies that predictably result in more extreme heatwaves, sea-level rise, food insecurity, or conflict for future populations.

Environmental degradation and resource depletion

Similar reasoning appears in debates about:

• Biodiversity loss and habitat destruction that permanently reduce ecosystem resilience.
• Long-lived pollutants and nuclear waste, which can impose health risks for many generations.
• Non-renewable resource depletion, such as fossil fuels, groundwater, or key minerals.

In each case, our current actions shape the economic and demographic conditions under which future people will live, and thereby which people exist. Yet many ethical and legal frameworks—such as sustainability principles or “safe minimum standards”—presume robust duties to avoid imposing heavy environmental burdens on future generations.

Use in policy analysis

Economists and policy analysts have drawn on these examples to question temporal discounting practices and to examine whether standard cost–benefit analysis adequately reflects concerns about distant future people. Climate ethics literature frequently invokes the Non-Identity Problem to interrogate whether harm-based, rights-based, or aggregate welfare frameworks better capture obligations to those who will live with the long-term environmental consequences of present choices.

9. Key Variations and Related Puzzles in Population Ethics

The Future Generations Problem is closely linked to a broader set of puzzles in population ethics, many of which concern how to compare outcomes with different numbers and identities of people.

Variations on the core problem

Several variants adjust aspects of the original structure:

• Same-people vs different-people choices: Some scenarios hold the population fixed (e.g., improving or worsening conditions for a given set of future individuals), while others, the classic Non-Identity cases, involve different individuals depending on choices.
• Threshold cases: Debates about the threshold of a life worth living explore whether there is a moral difference between creating people whose lives are barely worth living and those whose lives fall below that threshold.
• Near-future vs far-future: Some analyses suggest that identity effects may be smaller in near-term policy choices, but more pervasive for distant futures, leading to different moral assessments by timescale.

Related population-ethical puzzles

The following puzzles are often discussed alongside the Future Generations Problem:

These puzzles show that any attempt to resolve the Future Generations Problem by adopting a particular population-ethical rule must also confront broader issues about how many people should exist, at what levels of well-being, and with what kinds of trade-offs. As a result, some philosophers see the Future Generations Problem as part of a larger network of difficulties about evaluating outcomes with variable populations.

10. Standard Objections and Critiques

A sizeable literature challenges both the framing and the perceived force of the Future Generations Problem. Critics target different elements: the metaphysical assumptions, the person-affecting starting point, or the intuitive verdicts.

Prominent objections

Lines of critique

1. Against the metaphysics of identity: Some argue that the emphasis on individual identity is misplaced; what matters may be the persistence of cultures, institutions, or populations, not which numerically distinct individuals exist.

2. Against person-affecting constraints: Others contend that insisting on a person-affecting account of wrongness is optional; if one adopts an impersonal standard from the outset, the “problem” largely disappears, though new paradoxes emerge.

3. Against the severity of the puzzle: A further stance holds that the Future Generations Problem is theoretically interesting but does not fundamentally undermine moral practice, where mixed considerations of harm, rights, fairness, and prudence already guide policy.

These objections do not converge on a single alternative picture but collectively question whether the Future Generations Problem requires radical revision of moral theory, or whether it can be contained by adjusting particular premises or intuitions.

11. Impersonal and Population-Ethical Responses

One broad family of responses to the Future Generations Problem adopts impersonal or population-ethical principles, relaxing or abandoning the requirement that wrongness must be tied to making specific individuals worse off.

Impersonal consequentialism

Impersonal consequentialists hold that outcomes can be better or worse in virtue of their overall properties, such as:

• total sum of well-being (total utilitarianism),
• average well-being (average utilitarianism),
• or more complex functions of distribution and number.

On these views, policies that lead to better overall futures—more well-being, less suffering, more justice—are morally required, even if different individuals exist under different policies. This allows direct condemnation of high‑emissions or reckless policies as producing worse states of affairs, without needing to identify specific harmed individuals.

Wide person-affecting and quasi-impersonal views

Some theorists propose wide person‑affecting views that remain formally person-centred but approximate impersonal verdicts. For example, they may:

• compare how well “people as a whole” or “whoever exists” fare across outcomes, or
• count an outcome worse if it is worse for any possible person who might exist, not just actual ones.

These views aim to preserve concern for individuals while avoiding strict identity-based constraints that generate Non-Identity puzzles.

Population-ethical refinements

To escape paradoxes like the Repugnant Conclusion, philosophers have developed more intricate population-ethical theories:

• Critical-level utilitarianism, which subtracts a constant “critical level” from each person’s well-being when aggregating.
• Variable value theories, which adjust the value of additional lives depending on existing welfare levels.
• Axiological pluralism, combining welfare with other values such as equality, capabilities, or respect.

These frameworks seek to:

1. deliver robust concern for future generations,
2. handle identity-affecting cases, and
3. avoid the most counterintuitive population-ethical implications.

No single impersonal or population-ethical solution commands consensus, but this family of approaches illustrates one major strategy: accept that moral evaluation transcends person-affecting harm, and instead rank possible futures impersonally.

12. Person-Centred, Rights-Based, and Contractualist Responses

A second major family of responses retains a broadly person-centred focus but modifies how harm, rights, or justification are understood, aiming to account for duties to future generations without fully embracing impersonal aggregation.

Non-comparative harm and wronging

Some theorists, such as Elizabeth Harman and Seana Shiffrin, argue for non-comparative or constraint-based accounts of harm and wrong:

• A person can be harmed simply by being placed in a seriously deficient or unjust condition, regardless of whether they could have been better off.
• Creating someone into foreseeably harmful conditions—e.g., severe environmental degradation—can thus wrong that person, even if non-existence was their only alternative.

This approach preserves the idea that wrongful acts involve individuals being treated badly, while sidestepping the need for a better alternative for the same person.

Rights-based approaches

Rights theorists and legal scholars propose that:

• future persons, considered generically, hold rights to basic environmental quality, resources, or institutional justice; and
• current generations have correlative duties not to violate these rights.

For example, Edith Brown Weiss’s “planetary trust” concept treats humanity as a chain of trustees, each generation obligated to pass on a planetary environment meeting certain standards. Rights can be framed as attaching to “whoever exists” at future times, avoiding dependence on specific identities.

Contractualist and democratic extensions

Contractualist approaches, influenced by Rawls and later writers, extend principles of justification across generations:

• One asks what rules could be reasonably rejected by any generation, actual or future.
• Alternatively, one models an intergenerational original position, with parties representing successive generations under conditions of fairness.

These frameworks often emphasise:

• just savings principles, requiring each generation to sustain institutions and resources that make fair future cooperation possible; and
• constraints against exploiting temporal asymmetries (e.g., earlier generations acting unilaterally at the expense of later ones).

Person-centred, rights-based, and contractualist responses thereby seek to preserve a focus on individuals and mutual justification, while revising the understanding of harm, rights, or agreement to accommodate the special features of future generations.

13. Longtermism, Existential Risk, and Practical Implications

Recent philosophical and policy discussions connect the Future Generations Problem to longtermism and the study of existential risk.

Longtermism

Longtermism is the view that the long-term future may dominate the moral importance of our actions because of the vast number of potential future people. Many longtermist arguments:

• draw on the idea that the human future could span millions of years with very large populations;
• treat improving the long-term trajectory of civilisation as extremely morally significant.

Some longtermists adopt impersonal population-ethical assumptions; others take the Future Generations Problem as motivating strong concern for future people even on more person-centred views. Debates focus on how much present resources and political attention should be devoted to shaping outcomes far in the future.

Existential risks

Existential risks are threats that could annihilate humanity or irreversibly curtail its long-term potential (e.g., from advanced weapons, engineered pandemics, runaway AI, or uncontrolled climate change). In this context:

• preventing extinction is often portrayed as preserving the possibility of countless future lives;
• identity-affecting issues may appear less pressing, since extinction eliminates future people altogether.

Some argue that even modest probabilities of existential catastrophe justify prioritising risk reduction. Others question the robustness of such estimates or the ethical basis for prioritising potential future lives over current urgent needs.

Practical ramifications

The Future Generations Problem informs a range of concrete proposals, including:

• incorporating representatives for future generations in legislative processes;
• creating constitutional or legal protections for environmental and institutional inheritance;
• adjusting discount rates in cost–benefit analysis to give greater weight to far‑future impacts;
• designing governance structures for technologies with long-term, global consequences.

Supporters view these as ways to institutionalise concern for future people despite their lack of political voice. Critics worry about epistemic uncertainty, democratic legitimacy, and potential neglect of pressing present injustices.

14. Open Questions and Ongoing Debates

Despite extensive work, many issues surrounding the Future Generations Problem remain unsettled.

Theoretical open questions

1. Status of person-affecting morality: There is no consensus on whether person-affecting principles should be rejected, qualified, or preserved as central but incomplete. Debates continue over “wide” person-affecting views and mixed person/impersonal frameworks.

2. Nature of harm and wronging: Philosophers disagree about whether harm must be comparative, non-comparative, or pluralistic. The viability of non-comparative accounts in capturing everyday moral judgments remains contested.

3. Population ethics foundations: Efforts to develop consistent, intuitively acceptable axiologies that avoid the Repugnant and Sadistic Conclusions face formal impossibility results. Some argue that no theory can satisfy all our intuitive constraints simultaneously.

4. Moral weight of possible vs actual people: Questions persist about whether merely possible persons (who will never exist) can ground duties, and how to compare scenarios involving different sets of potential persons.

Methodological and practical debates

• Role of intuitions: Some urge revising our intuitions in exotic cases; others treat these intuitions as data that constrain acceptable theories.
• Handling deep uncertainty: Assessing long-term impacts involves uncertainty about technology, values, and demographics. How to incorporate such uncertainty into ethical evaluation remains disputed.
• Balancing near and far futures: There is ongoing disagreement about how to trade off benefits to current, identifiable people against speculative benefits to distant future generations, especially under resource constraints.

Interdisciplinary questions

Political theorists, economists, and legal scholars debate:

• how to design institutions that respect both democratic legitimacy and intergenerational responsibilities;
• whether future generations should be represented through ombudspersons, constitutional clauses, or other mechanisms;
• how ethical conclusions about discounting, risk, and justice should translate into concrete policy rules.

These open questions ensure that the Future Generations Problem remains an active and evolving area of research.

15. Legacy and Historical Significance

The Future Generations Problem has had a substantial impact on late 20th‑ and early 21st‑century philosophy, as well as on adjacent fields such as law, economics, and environmental policy.

Philosophical legacy

Within moral and political philosophy, the problem:

• helped establish population ethics as a distinct research area, inspiring extensive work on axiologies for variable populations;
• challenged traditional accounts of harm, rights, and justice, prompting refinements of person‑centred, contractualist, and rights‑based theories;
• reshaped debates on utilitarianism and other consequentialist theories by highlighting the importance of future people and the difficulties of aggregating over them.

Parfit’s treatment has become a standard reference point, with many subsequent works defining their positions partly in relation to his Non-Identity Problem and related puzzles.

Influence beyond philosophy

In legal and policy domains, arguments about duties to future generations have contributed to:

• the development of concepts such as sustainable development and intergenerational equity in international law;
• constitutional provisions and statutory measures in some jurisdictions recognising obligations to future citizens or future generations;
• refinement of cost–benefit analysis, especially debates over intergenerational discount rates and the valuation of long-term environmental harms.

Climate ethics, nuclear waste policy, and discussions of technological risk frequently draw on insights from the Future Generations Problem to question short‑termist decision-making.

Ongoing significance

The problem continues to inform emerging areas such as existential risk studies and longtermism, where concerns about vast futures and identity-affecting actions are central. It also serves as a key example of how abstract metaphysical issues—about personal identity, existence, and possibility—can bear directly on practical ethical questions.

As a result, the Future Generations Problem is widely regarded as a landmark development in contemporary moral and political thought, shaping how philosophers and policymakers alike conceptualise our responsibilities to those who will live after us.