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# Commitment, Kantian Economics and Climate Change: Rethinking Rational Choice and Individual Responsibility

Mathieu Guigourez

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Mathieu Guigourez. Commitment, Kantian Economics and Climate Change: Rethinking Rational Choice and Individual Responsibility. 2025. halshs-04974741

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CES

Centre d'Économie de la Sorbonne
UMR 8174

Commitment, Kantian Economics and Climate Change:
Rethinking Rational Choice and Individual
Responsibility

Mathieu GUIGOUREZ

2025.02
# Commitment, Kantian Economics and Climate Change: Rethinking Rational Choice and Individual Responsibility

Mathieu Guigourez *†

2025

## Abstract

Individual actions – and individual responsibility – in regard to climate-related issues are often overlooked because they have a negligible impact at the global scale. Yet, despite having little to no impact, some people commit themselves to reducing their carbon footprint; that is, they are willingly choosing to adapt their consumption despite having no tangible impact on the issue they are tackling. Our aim is to question the permeability of economic rationality with moral (individual) responsibility at stake in climate-related issues. We provide an account of a possible bridge between deontological obligations and utility-maximisation in three different frameworks, namely Senian commitment, Kantian economics and choice under unresolved valuations conflicts. This analysis of different frameworks incorporating deontological motives in Rational Choice Theory analytically grounds individual commitments without relying on political enforcements or monetary incentives.

Keywords: Rational Choice Theory; Amartya Sen; Individual Responsibility; Kantian Economics; Normative Uncertainty; Commitment; Climate Ethics; Normative Decision Theory.

JEL Codes: B41; D01; D72; D81

## Introduction

Climate-related issues raise specific objections to standard Rational Choice Theory (RCT henceforth) as they usually involve a counter-preferential choice (Sen, 1977). Furthermore, individual actions – and individual responsibility – in regard to climate-related issues are often overlooked insofar as 1) they have a negligible impact on the global scale and 2) it is almost impossible to trace back the occurrence of climatic harm to one particular individual or their doing (Sinnott-Armstrong, 2005; Kingston

<footnote>*CONTACT: mathieu.guigourez@univ-paris1.fr</footnote>

<footnote>†Université Paris 1 Panthéon-Sorbonne, Centre d'Économie de la Sorbonne, France</footnote>
and Sinnott-Armstrong, 2018). Suppose that you need to go to work and you can do so either by taking your bike or your car. Taking your bike is surely more costly than taking your car<fnref n="1" />. Still, you do think that the climate crisis needs to be addressed and taking your car might add to the problem. Thence, you may ask yourself: is it up to me to do something even though my individual doing might make no difference? In evaluating these two options (i.e taking your car or your bike), you can adopt a consequentialist framework or a deontological one. When dealing with the ascription of individual responsibility, philosophers usually adopt a consequentialist type of evaluation (Parfit, 1984; Johnson, 2003; Sinnott-Armstrong, 2005; Kagan, 2011; Nefsky, 2012; Braham and van Hees, 2012, 2018; Thompson, 2014; Kingston and Sinnott-Armstrong, 2018): one looks at the harm ensued from the emission of greenhouse gases, and fails to assign a level of individual *causal* responsibility<fnref n="2" />. Similarly, economists also adopt a consequentialist framework (Sen, 2000; Hammond, 1988, 1997; Frank, 1987; Lenzen and Murray, 2010): the very notion of 'expected utility', as developed by von Neumann and Morgenstern (1944) and Savage (1954), is a consequential evaluation of at least two different options. The deontological framework, on the other hand, in its accommodation to maximising expected utility, sets a predicament for economists and decision theorists: how can the agent be, at the same time, morally committed and rational in their behaviour?

The main objective of this article is to question the permeability of economic rationality with moral (individual) responsibility at stake in climate-related issues. To do so, we delve into different definitions of rational choice and deontological commitments and ask: upon what criterion can an act of choice be judged rational and still take into consideration moral imperatives? Thus, in contrast to consequential evaluations of individual responsibility (*authorship*, *accountability*, *liability*, etc. for instance) we conceptualize it as a deontological obligation that the individual rationally chooses. Following Sen (1977, 2000, 2004), we argue that climate-related issues and individual obligations offer strong objections to standard rational choice theories, but they can still be subject to utilitarian maximisation. In other words, we wish to make an ambitious bridge between deontological obligations and utilitarian rationalization of behaviours. This may seem counter-intuitive at first, as Sen (2000, p.493) highlights:

<footnote n="1">¹One could argue that there are more long-term health benefits in taking your bike rather than your car, but we do not take these into consideration in this example as it is a one-shot decision.</footnote>

<footnote n="2">²Note that, in this literature, several arguments are developed: Johnson (2003); Sinnott-Armstrong (2005); Kingston and Sinnott-Armstrong (2018) argue that this missing causal link prevent us from conceptualising an individual moral responsibility, yet there exists a responsibility in challenging government and larger institutions to act; Hourdequin (2010) differs, against them, in her conceptualisation individual responsibility as she defines it as a moral integrity between your political positions and your actions; Thompson (1980, 2014); Braham and Van Hees (2011); Braham and van Hees (2012) do not strictly deal with the climate crisis, yet they delve into the problem of ascribing moral responsibility in problems of ‘many hands’ and ‘responsibility voids’ that is when a collective outcome is reached but no individual can claim its responsibility; finally Parfit (1984); Kagan (1988, 2011); Nefsky (2012, 2017, 2019, 2021) argue that even in cases when an individual cannot make any difference, there is still a moral reason to tackle the problem insofar as we may have a *contributive* responsibility. Kagan and Nefsky do so by adopting an expected-utility framework: since there is a *risk* that your action might trigger collective harm, you can thus estimate a probability of your action being a trigger case and assign expected utilities to different outcomes.</footnote>
‘Utilitarians do not include the realization of freedoms, or the fulfilment of rights or duties among the valued objects at all, and so there is a fundamental gap here’, but this is precisely the gap this paper aims to fill as its main contribution.

Our method is to delve into three frameworks that aim at incorporating moral considerations in rational choices<fnref n="3" />. The first framework – and first section of the article – is explicitly ‘Senian’ in the conception of commitments regarding climate-related issues (Sen, 1973, 1974, 1977, 1997, 2010). Sen has been the first one to introduce sorting waste as a strong critique to standard rational choice theory (Sen, 1973); yet when specifically dealing with ‘the act of choice’, Sen (2000, p.477) argues that consequential evaluations are the ‘discipline of responsible choice’ due to the limited reach of deontological approaches. In order to account for deontological approaches, we delve, in the second section, into Kantian Economics. Following Laffont (1975); Etzioni (1987); White (2004, 2006, 2009, 2019) we delve into the introduction of moral imperatives in RCT and build on their contributions. Kantian economists are interested in acts of choice in which the individual cannot make any difference (such as voting in a large election) but still chooses to commit themselves without any incentive or coordination concern. We distinguish between two accounts of Kantian Economics, namely teleological and deontological accounts, and argue in favour of the latter. However, identifying and incorporating a precise ‘perfect duty’ to curb our greenhouse gas emissions into a choice or utility function is still a quandary for the economist. Hence, in the third section, we expand our analysis to unresolved valuational conflicts at stake in our first example (taking your bike or your car to go to work) as the last framework to account for ecological behaviours. In order to account for these internal conflicts at stake in ecological commitments, we delve into the Choice under Normative Uncertainty and Hard Choices frameworks. This framework does not specifically deal with climate-related issues but encompasses a wider array of ethical problems in which no clear duty can be inferred. The ‘Choice Under Normative Uncertainty’ framework has elaborated several theories to elucidate the act of choice when two or more options seem equally or ambiguously permissible (MacAskill, 2016; MacAskill et al., 2020; Bykvist, 2015, 2017; Tarsney, 2018; Dietrich and Jabarian, 2021, 2022). In assessing your choice of taking your bike or your car through an ‘expected choice-worthiness function’ we are able to account for such commitments as being both deontological and maximising behaviours. Hard Choices have been discussed by Sen (2004) and Chang (1997, 2017, 2024); Tenenbaum (2024) as an account of rational choice (e.g. a maximising behaviour) upon incommensurable values. In the last section of this paper we address the relevance of such an analysis of individual responsibility and rational choice theory.

<footnote n="3">³There are numerous other frameworks seeking to introduce moral considerations in decision theory and more broadly rational choice theory (see for instance Harsanyi (1955, 1977, 1985)), but for the sake of clarity and of length, I will restrain my analysis to three frameworks that are compliant to one another.</footnote>
Our paper offers a redefinition of moral responsibility understood beyond its causal (and consequential) acceptance. In other words, it defines an individual responsibility as an urge to take part in ethical issues regardless of your causal contribution to the problem. The significance of our conception of individual responsibility is to be applied even in cases where individual commitments do not make any difference in the evaluation of different outcomes. This conception of responsibility challenges our conception of RCT insofar as such ecological commitments can be considered completely rational, despite having no impact and implying a lower level of personal welfare. Such a conception of ecological responsibility does not need to be at odds with rational choice theory, as both are compliant with one another.

# 1 Rationality and Commitments

Suppose that the individual chooses to take their bike to go to work even though it is more costly for them than taking their car. One way of accounting for such a choice is to consider it as a commitment. The ‘commitment’ framework is developed by Sen (1977, 1985) as a critique of standard RCT to account for moral and ethical considerations in the act of choice. Commitments, according to Sen, can be quickly defined as acting on ethical considerations (such as fighting against injustice) that do not necessarily comply with the maximisation of personal welfare (Sen, 1977, p.317).

## 1.1 Preference, Choice, Welfare in Rational Choice Theory

More precisely, Sen's main critique of what he calls 'standard Rational Choice Theory' is the conflation of choice, preferences and welfare (Sen, 1973, p.252). To Sen, since Samuelson (1938)'s Revealed Preference theory, economic theory has conflated preferences and choice (insofar as our preferences are necessarily defined by our choice), and thus choice to welfare (as our choices reflect our personal welfare). Sen (1973, p.253) argues that individual preferences are ambivalent insofar as they are considered both as 'determinants of behaviour' and at the same time 'the basis of welfare judgments.' Yet, some ethical considerations may be determinants of one's behaviours while not complying completely with the pursuit of personal welfare. Let us, first, quickly define Sen (1973)'s notion of preference. A preference is defined here as a binary relation between two alternatives (*x* ≻ *y* ; *y* ≻ *x* ; *x* ~ *y*) which usually satisfy at least two axioms postulated by the economist that constitute a rational choice:

* Internal consistency: if *x* is observed to be preferred by the agent over *y*, then in all possible rankings, *x* ≻ *y*.
* Completeness: there is a clear preference ordering or indifference and such ordering should be transitive, that is if $x \succ y$ and $y \succ z$, then $x \succ z$.

Given these axioms, an agent can have a complete ordering and, thus, choose the most optimal alternative, that is, the one being no inferior to any other alternative that is also available. Preferences, thus, do not refer to any psychological status as they only indicate a consistent, complete and/or transitive ordering between at least two alternatives. As preferences imply a binary relation of two alternatives, it usually refers to one valuation metric (utility) that is used to compare these two alternatives. If an agent A chooses the bundle $x$ (taking your car) when the bundle $y$ (taking your bike) is also available, then we can infer that $u(x) > u(y)$. Such inference seems to imply that ecological commitments (choosing a sub-optimal option for ecological considerations while another optimal option is available) are deemed irrational. Elster (2010, p.55) distinguishes two ways of understanding irrational behaviours in economics: either 1) the agent actually is irrational (in a cognitive way) or 2) Rational Choice Theory is under-determined to grasp a wider array of behaviours fully. If you have to rank $x$ and $y$, taking your bike ($y$) appears suboptimal insofar as it yields the same outcome (climate change will not budge via your individual action) for a higher cost. As an economist, we could thus infer that $u(x) > u(y)$. To Sen (1974, p.65): '[r]ationality, as a concept would seem to belong to the relationship between choices and preferences; and a typical question will take the form: 'Given your preferences, was it rational for you to choose the action you have chosen?' (...) Morality would seem to require a judgement among preferences rationality would not.' This distinction highlights an impermeable discrepancy between RCT and moral philosophy, as the former establishes a judgement based on internal axioms whereas the latter establishes judgements based on practical reasoning. In other words, Sen argues that in the framework of RCT '[w]e count, not judge' (Sen, 2004, p.55). This limited approach of rational choice derives from using a single valuation metric (utility) derived from revealed preferences. Sen conceptualizes 'commitments' as a way to account for ethical considerations that do not necessarily comply with utility or welfare maximisation.

More specifically, ecological commitments have been a long-dated opposition to standard rational choice theory and thus highlight its underdetermination (Sen, 1973, 1977). Sen (1977) develops the notion of commitment as a way to critique Edgeworth and Sidgwick's 'economic calculus' when it comes to ethical questions and utilitarianism. Sen (1977, p.317-326) defines a commitment as follows:

> 'a person choosing an act that he believes will yield a lower level of personal welfare to him than an alternative that is also available to him. (...) The characteristic of commitment with which I am most concerned here is the fact that it drives a wedge between personal choice and personal welfare, and much of traditional economic theory relies on the identity
of the two.'

Commitments, to Sen, avoid falling into a narrow conceptualisation of rational choice theory that produces what he calls ‘rational fools’, i.e., agents that are only moved by the will to maximise their expected self-interest in spite of any ethical consideration. Besides, Sen conceived commitment as a way to analyse – and rationalise – actions in which the agent deliberately chooses to lower their welfare in regard to ethical considerations. These commitments may comply (but not necessarily) with counter-preferential choices. In other words, these commitments constitute a prime example of a choice which may contradict the standard pursuit of personal welfare:

> ‘The main issue is the acceptability of the assumption of the invariable pursuit of self-interest in each act. Calling that type of behavior rational, or departures from it irrational, does not change the relevance of these criticisms, though it does produce an arbitrarily narrow definition of rationality.’ Sen (1977, p.343)

If we are to broaden the scope of rational choice theory so as to incorporate ecological behaviours – and deontological obligations more broadly– we must, thus, dissociate preferences, choice, and personal welfare. The criterion of Rationality comes into play in these three notions at different levels: while *preferences* only seem to indicate a binary relation between two (or more) alternatives, some *choices* may be inconsistent with RCT’s axioms. Moreover, commitments indicate that individual *choices* are not always consistent with personal *welfare*. While the individual may well be rational in having *reasons* to behave the way they behave, an economist may label such commitments as irrational as they violate RCT’s axioms. As Sen (1973, p.243) argues, ‘what makes them look inconsistent is precisely the peep into the head of the consumer, the avoidance of which is alleged to be the aim of the revealed preference approach.’ In a later work, Sen (2010, p.178) distinguishes ‘Rational Choice’ and ‘so-called Rational Choice theory.’ More specifically, he defines a rational choice as one in which the reasons for it can be sustained even under scrutiny; on the other hand, Sen (2010, p.179) RCT as the ‘smart maximisation of self-interest’ which may include other-regarding preferences, sympathy or broader ethical values which either relieve me from sufferance or indirectly causes me good. In conceptualizing commitments, Sen, thus, aims to break the constitutive inference between preference and choice, and moreover between choice and welfare so as to enrich the possible determinants of the ‘act of choice’. One way of accounting for such commitments is to consider meta-rankings (a ranking of rankings) of preferences and ‘as-if’ rankings.
## 1.2 Meta-Rankings and As-If Rankings

### 1.2.1 As-If Rankings

The main relevance of commitments is made obvious in game theory, and more precisely in situations called Prisoner's Dilemmas (Sen, 1973, 1974, 1977). In this approach two prisoners are facing a trial for a very serious crime and are both facing heavy penalties but there is not enough evidence to convict them. Here are their strategies: if they confess the crime while the other prisoner does not, then the confessor is charged with, say a 20-year sentence for instance while the other runs free. But if they both confess, they are both charged with 10 years and if they both refuse to confess, they are both charged with 2 years for instance. In this game, there exists a dominant strategy to confess: if the other player confesses, you are better off confessing, but if the other player does not confess, you are still better off confessing. The famous result of this dilemma is while both prisoners can infer the most optimal strategy for them, the result of this game is Pareto sub-optimal. Sen introduces such a game with environmentally friendly behaviours (namely returning glass bottles to avoid waste) Sen (1973, p.254): 'Being generally interested in the environment but also being lazy about returning bottles, this person may be best off if the others return bottles but not he, next best if all return bottles, next best if none does, and worst of all if he alone returns bottles while others do not.' Regarding commitments, Sen focuses on cases of cooperation (that is, every player chooses to return their bottles, or 'not to confess' in the case of the prisoners, regardless of everyone else's strategies) without any monetary incentive or contract made by the two prisoners: he analyses cooperation (and individual commitment not to confess) as if it was consistent with an 'as-if' or imaginary welfare function. Sen (1973, p.252), 'The essence of the problem is that if both prisoners behave as if they are maximizing a different welfare function from the one that they actually have, they will both end up being better off even in terms of their actual welfare function.' Hence, when describing a situation of commitment, Sen incorporated a second welfare function, as if the agent was maximising it instead of their so-called true welfare function and preferences. In other words, in committing themselves, the agent behaves as if he could choose not to follow their revealed preference but make a judgement on their options to choose the one that can sustain their ethical considerations. The act of choice, to Sen, must thus encompass more than the mere observation of the option chosen by the agent, it must also account for the agent's ranking of their rankings. Economists and decision theorists must be able to account for behaviours consistent with 'as-if' preferences. Peacock (2019, p.57) argues that actions based on an as-if ranking break free of the preference-based aetiology in RCT. In other words, as-if rankings constitute strong objections to the identification of preferences as determinants of choice, what Peacock (2019, p.13) calls the 'aetiological relationship'.
1.2.2 Meta-Rankings

Sen's main argument is to enrich the *structure* of rational choice rather than trying to enrich its objects. Sen (1974, p.62) argues for a 'ranking of rankings' in which a meta-ranking of the possible rankings may account for moral judgements over different rankings. In *Choice, Orderings and Morality*, Sen (1974) does not conceptualize the notion of commitment *per se* but argues that 'meta-rankings' may reconcile individual rationality and social optimality. To Peacock, this moral meta-ranking of options is not an argument for a deontological approach to RCT but to accommodate moral judgements over different sets of options: Peacock (2019, p.62) 'With the apparatus of moral meta-ranking, one can achieve a finer-grained conception of morality, whereby morality can be conceived as a graded phenomenon, a matter of more or less, rather than all-or-nothing.' Such a focus on meta-rankings serves as a possible explanation of commitments. More precisely, Sen (1977, p.339) argues that meta-rankings can express the preferences an agent would have liked to have, and he takes for instance: 'I wish I liked vegetarian foods more.' In this example, the agent has a specified ordering of what they would order in a restaurant, they would first prefer to take a meat-based meal (call it option *x*), or else they would then prefer to take the vegetarian option (*y*). In this context, they rank *x* ≻ *y*, call it ranking *A*; but they also recognize that climate-related issues or animal welfare are to be addressed and would also recognize a second ranking where they choose the vegetarian option (*y* ≻ *x*), call it ranking *B*. You can now have a ranking of your different rankings, a 'meta-ranking' upon which moral and ethical considerations may apply and account for individual commitments. If our individual chooses the vegetarian option while the other meal is also available, then this form of commitment can be explained as following a meta-ranking in which *B* ≻ *A*.

Meta-rankings are not completely identical to as-if rankings in Sen's framework. Meta-rankings only regard decision theory and allow us to express moral judgement over different rankings; as-if rankings, on the other hand, are displayed in game-theory and more precisely in the Prisoners' Dilemma in which '[the agent] has asked himself what type of preference he would like the other player to have, and on somewhat Kantian grounds has considered the case for himself having those preferences, of behaving as-if he had them.' Then, if I choose to take my bike while I could also take my car to go to work, there are two ways of accounting for such a commitment according to this framework. Either 1) I express a moral judgement over the two possible rankings (*x* ≻ *y* or *y* ≻ *x*) and choose the meta-ranking that I judge ethically or morally better, or 2) I ask myself 'What is the strategy I would want us all to adopt?' and act as if everyone acted in such a manner.
## 1.3 A Redefinition of Outcomes and Goals in the Act of Choice

To Sen, if we are to broaden RCT so as to comprehend ethical considerations, one needs to develop the processes leading to a choice as something much more complex than a mere pursuit of personal welfare. To this end, (Sen, 1985, 2005) develops possible reasons determining an individual's choice, and more precisely what comes into consideration. (Sen, 1985)(p.347) distinguishes

* Self-Centered Welfare in which '[a] person's welfare depends only on his or her own consumption', that is the most basic (and hedonistic) understanding of personal welfare.

* Self-Welfare Goal in which '[a] person's only goal is to maximize his or her own welfare', that is a basic definition of the pursuit of self-interest as the main determinant of one's behaviour.

* Self-Goal Choice in which '[e]ach act of choice of a person is guided immediately by the pursuit of one's own goal.' The notion of goal here is broadly understood and can incorporate altruistic goals (satisfying the other's goals as part of our own self-goal; acting upon moral obligation etc.).

This distinction has led Pettit (2007, p.31) to define commitments as 'goal-modifying' (I take into consideration other people's goals and incorporate them in my own goal) and 'goal-displacing' (I take into consideration other people's goals and place them above my own goal). The goal-modifying acceptance of commitment is easily suitable to standard (yet somewhat enlarged) RCT as the individual will end up maximising his self-centered welfare with new constraints (other people's goals). To Sen (1985), if one broadens the conceptualisation of the 'self' involved in rational choice theory, we may be able to account for broader reasons which causally orientate one's choice. Whence, a striking discrepancy in Sen's literature: while the commitment framework accommodates ethical and deontological motives in RCT, when Sen specifically deals with 'the act of choice', he (Sen, 2000, p.477) argues that consequential evaluations are the "discipline of responsible choice based on the choosers evaluation of states of affairs." This can be explained by the focus on 'goals' and 'identity in Sen's later (that is, in this precise context, in the 1980's) work on commitment which shifts the focus from moral meta-rankings to broader conceptualisation of the reasons leading to a commitment. Sen (2000, p.483-484) defines the consequential evaluation system according to three subjects:

1. Situated evaluation: what is the standpoint of the evaluator when doing their evaluation? Sen distinguishes 'impersonality' that may be required in ethics from 'impositionality' which would ignore the evaluator's situation from the choice and the outcome<fnref n="4" />.

2. Maximising framework which (Sen, 2000, p.486) defines as not choosing 'an alternative that is worse than another that can be chosen instead'.

<footnote n="4">⁴On this argument, Sen differs from Harsanyi (1955, 1977, 1985)'s impositionality standpoint. One can see Sen's critiques (Sen, 1976, 1993) or Greaves (2017)' overview of this debate.</footnote>
3. Nonexclusion of state components: or as (Sen, 2000, p.484) states ‘Are all features of the consequent states of affairs potentially relevant?’ In other words, every state of affairs – including prohibitions, motivations, social norms or laws – in the occurrence of the outcome must be taken into consideration if it is relevant to the consequences of the outcome.

This leads Sen (2000, p.491) to a redefinition of ‘outcomes’ in order to encompass various reasons that may be determinant in the act of choice, and thus, in the consequences of the outcome. Sen distinguishes ‘comprehensive outcomes’<fnref n="5" /> that include ‘the action and the processes along with the final outcome’ from ‘culmination outcomes’ which only regards ‘what happens at the very end.’ When looking at our first example, taking your car or your bike, the culmination outcome is given if you look at the global scale: climate change will occur no matter your choice of transport. Hence, the culmination outcome may not be up to individual authorship (insofar as no individual can prevent the climate crisis from happening), but this does not mean we should completely disregard the comprehensive outcome to account for ecological commitments. Taking your bike may, thus, be the expression of several reasons underlying your compliance with ethical imperatives.

Sen's conceptualisation of commitments helps account for volitional ecological behaviours yielding a lower level of personal welfare when another (more polluting) option is available. However, the consequential evaluation of responsibility still leaves open the question: When the outcome is given, can we still account for ecological commitments that are purely deontological? As such, we now turn to a Kantian framework to move beyond a consequentialist framework.

# 2 Kantian Morality and Rational Choice Theory

Kantian Economics is an umbrella term encompassing a wide array of subfields such as microeconomics (Roemer, 2010, 2015, 2019; Josheski et al., 2025; van Leeuwen and Alger, 2024), social choice theory (Gravel et al., 2000; Alger and Weibull, 2013; Alger and Laslier, 2022; Laslier, 2023; Dierks et al., 2024), and methodology of economics or rational choice theory (Laffont, 1975; Etzioni, 1987; Ellerman, 1988; White, 2004, 2006, 2009, 2019). They all share a common background: Kant's conception of morality and its formal law, even if some interpretations still differ.

## 2.1 Critic of Utilitarianism

One of the main characteristics shared by this subfield is its aim to renew its criticism against utilitarianism and some dead-ends such as volitional commitments yielding a lower level of personal welfare. More precisely, the general ambition of Kantian economics can be understood as ‘the possibil-

<footnote n="5">⁵This term has been coined by Rawls (1971) as Sen (1997, p.749) confesses.</footnote>
ity and the consequences of collective behaviour (without any direct communication between agents) that is in contradiction to the maximization of direct personal interest' (Laffont, 1975, p.430)<fnref n="6" />. In what White (2004, p.101) call the 'multiple utility framework', moral imperatives take the form of another utility function composed of self-imposed constraints, other-regarding preferences, etc. which may differ from the fixed set of self-regarding preferences. For instance, Etzioni (1987, p.38) argues that the notion of utility must be enriched (in what he calls 'bi-utility') to account for both the satisfaction of preferences and 'living up to one's moral obligations'. Laffont (1975, p.430) has quite a similar argument as he reformulates Kant's universalisation criterion of the moral law: '[w]e postulate that a typical agent assumes (according to Kant's moral) that the other agents will act as he does and he maximizes his utility function under this new constraint.' This acceptance is quite far from Kant's categorical imperative ecome a universal law' (Kant, 2019)[1785]) but it has been used in game theory and microeconomics to develop a 'Kantian Equilibrium' which, unlike Nash Equilibrium, is Pareto efficient<fnref n="7" />. But the discrepancy between Kant's categorical imperative and Laffont or Roemer's interpretation is not anecdotical, rather it highlights two possible interpretations of such an imperative in Kantian Economics and ethical behaviours.

## 2.2 Teleological and Deontological Rationalities

### 2.2.1 The Teleological Account of Kantian Economics

I argue that Roemer's and Laffont's conception of Kant's categorical imperative is teleological rather than deontological. Roemer (2019, p.viii) defines 'Kantian optimisation' as such: ' "What is the strategy I would like all of us to play?" I call this Kantian optimization, because it seems like a natural interpretation of Immanuel Kant's categorical or hypothetical imperative: take those actions that you would will be universalized'. Roemer's 'natural interpretation of Kant's categorical imperative' fixes a universalisable good that maximises the collective welfare and thus infers a rule of action. Following Rawls (1971, p.24)'s definition of teleological theories: 'the good is defined independently from the right, and then the right is defined as that which maximizes the good', Roemer's account of the categorical imperative is, thus, teleological insofar as it seeks to reach an optimum independently of any consideration of what is right or what are moral rules of actions. Kant, on the other hand, infers a moral law from a practical use of our reason to frame the right analytically. We, thus, define a Kantian teleological theory as one who puts the good (to be broadly constructed as incorporated in something close to self-interest, or at least to Pareto improvement) as the leading factor to explain

<footnote n="6">⁶To that extent, these economists and philosophers of economics share the same objective as Sen (1973, 1977). The resemblance between Laffont (1975) and Sen (1973) returning bottle argument is even more striking as Laffont uses the example of sorting beer cans on the beach and decides not to treat it as a problem of externality but of decision theory.</footnote>

<footnote n="7">⁷When conceptualizing such a Kantian equilibrium Roemer (2010, p.2-3) directly quotes Laffont (1975).</footnote>
one's motivation in committing themselves (to vote, to lower their carbon footprint, etc.). As a matter
of fact, our example of taking your bike or your car is quite similar to that of voting: whether you take
your bike or your car, you won't make any difference in the occurrence of climate change; and the same
goes for voting, no matter your personal vote, it won't affect the general result. But if you ask yourself:
what is the strategy that I would want everyone to play, independently of coordination or information
problems, then you are putting your conception of a greater good as the principle of your action. This
teleological account has led some Kantian economists to adapt the Kantian framework to voting (Alger
and Weibull, 2013; Alger and Laslier, 2022; Dierks et al., 2024). In their framework, they rely on a
Kantian groundwork for two main reasons: 1) to account for a model of ethical behaviours and 2) to
use a criterion for universalisation. Alger, Weibull and Laslier define a rational archetype, what they
call ‘homo moralis’ (Alger and Weibull, 2013, 2016, p.2272; p.61), in between *homo economicus* who
is moved by the sole pursuit of their self-interest, and ‘homo kantientis’ who strictly follows Kant’s
categorical imperative:

*Homo moralis* attaches some weight to the goal of ‘acting according to that maxim whereby you can, at the same time, will that others should do likewise with some probability.’ More precisely, a *Homo moralis* individual in a group of arbitrary size *n* > 1 maximizes a weighted average of equally many terms, indexed *k* = 0, 1, ..., *n*−1, where each term is the material payoff that she would obtain if, hypothetically, she could replace the strategies of so many other individuals in the group by her strategy. (Alger and Weibull, 2016, p.57)

Their model of voting develops a similar understanding:

The driving force is a form of ethical preferences –dubbed *Homo moralis*– which can be
interpreted as capturing a form of universalization: when contemplating a course of action,
a *Homo moralis* evaluates what his material payoff would be if, hypothetically, a share of
the population to which he belongs would follow the same course of action, where $κ$ is the
individual’s degree of universalization. (Dierks et al., 2024, p.2).

In such an account of Kant's categorical imperative, agents go to the voting booth as a strategic be-
haviour insofar as '[v]oting is the right thing to do because there would be bad consequences if too
many people abstained." As such, this account of ethical behaviours is the paragon of a teleological
acception of Kant's categorical imperative; people commit themselves to voting so as to avoid bad
consequences resulting from a general abstinence. The right is thus derived from a quest for social
optimality.

Such a teleological account can also be found in a Kantian equilibrium. Roemer (2019, p.13) de-
fines it as such: '[i]n a symmetric game, the strategy that each would prefer all to play is a simple Kantian equilibrium (SKE). I invoke Immanuel Kant here because of his categorical and hypothetical imperatives, which state that one should take those actions one would like to see universalized.' What Roemer misses in his interpretation here is that Kant's imperatives do not set a criterion for cooperation (or any other-regarding criterion) but a criterion for (individual) judgement over rules rather than over actions, and such a criterion cannot be deduced by inclination, yearning or desires but from a practical use of our reason. This critique has been addressed by Braham and Hees (2020, p.32): 'the CI [Categorical Imperative] is about the universalization of an agent's maxims rather than her actions and it does not refer to utility maximization.' These understandings of Kantian put an ex-post benefit (avoid potentially bad consequences, address the Tragedy of the Commons, achieve a Pareto Efficient equilibrium) which ought to be universalized in order to postulate an ex-ante rule of action, hence its teleological understanding. Our account of such teleological theories is twofold: on the one hand, we argue that the very notion of the Moral Law (from which the categorical imperative is derived) is purely formal and can never be defined by its object (the good) but is always defined by its legal form Kant (2015, V, 62)[1788]<fnref n="8" />. This argument follows Grandjean (2016, p.73) account of the moral law: 'Kant shows that a Good that precedes reason never precedes empirical desiring subjectivity, whose particularity would thus be elevated to the rank of an exclusive axiological instance. The Good that precedes reason has no other identity than that of what does good (to me). Any kind of intellectualism is a refined hedonism.' On the other hand, the notion of 'refined hedonism' to account for such teleological conceptions is not a critique *per se* against them, but highlights their resemblance with what Pettit (2007) called 'goal-modifying commitments' and can thus be subject to any sort of Expected Utility Maximisation framework. This follows Broome (1992, p.274)'s account that any teleological theory is 'one that aims to maximize specifically *good* rather than something else, and this seems to be a matter of substance as well as structure.' More precisely, such a critique does not invalidate any teleological Kantian theories, but it does not fit our problem of ecological behaviours and must, thus, be refined.

<footnote n="8">⁸Here is the original definition of the moral Law by Kant (2015, V, 62)[1788] to which we refer: 'Either a rational principle is already thought as in itself the determining ground of the will without regard to possible objects of the faculty of desire (hence through the mere lawful form of the maxim is taken to be practical of itself). In that case the law determines the will immediately, the action in conformity with it is in itself good, and a will whose maxim always conforms with this law is good absolutely, good in every respect and the supreme condition of all good. Or else a determining ground of the faculty of desire precedes the maxim of the will, which presupposes an object of pleasure or displeasure and hence something that gratifies or pains, and the maxim of reason to pursue the former and avoid the latter determines actions which are good with reference to our inclination and hence good only mediately (relatively to a further end, as means to it), and such maxims can in that case never be called laws but can still be called rational practical precepts'</footnote>
2.2.2 The Deontological Account of Kantian Economics

Following White (2019) and Kant (2015, V,62)[1788] we define a Kantian deontological theory as one who puts the ‘the capacity and responsibility of all rational beings (or persons) to determine their own wills and make decisions for the right (moral) reasons even when such choices go against their own preferences’ (White, 2019, p.56). Unlike its teleological account, this one is centered on moral autonomy. As White (2004, p.98) puts it: ‘[i]f we understand preferences and constraints to be (to some extent) subject to conscious control, we can imagine agents choosing to follow Kantian duties autonomously by incorporating them into their decision-making framework. As it happens, perfect and imperfect duties correspond closely to constraints and preferences, respectively.’ By perfect and imperfect duties, White recalls Kant’s distinction of duties (White, 2004, p.93): a perfect duty is ‘one that must be followed’, that is independently from any evaluation of the expected consequences, one’s desires or interests. These perfect duties are usually negatively defined (do not lie, do not steal, do not consider a person as a mean but always as an end) and can be thus included in one’s decision framework as self-imposed constraints, just as any other financial or economic constraints. On the other hand, an imperfect duty is wider and ‘merely suggest ends’ (White, 2004, p.94) and can take the form of benevolence for instance. White’s conceptualisation of Kant’s categorical imperative is quite abundantly deontological, as he recalls ‘the categorical imperative derives purely from the use of reason alone (...), from pure deduction based on consistency and respect for the rational nature of humanity.’ This deontological account of Kant’s categorical imperatives thus differs from teleological accounts (which postulate the good ex-post) by defining ex-ante the right (perfect duties) and accounting for the good (imperfect duties). In such a conceptualisation, White aims to reconcile deontological obligations with utilitarian maximising behaviours:

If the agent can rank some duties higher than other duties as well as inclination-based preferences, and can do so completely and transitively, then these duty-based preferences can be included in an ordinal utility function just as can any other set of preferences. The resulting utility function can then be maximized according to the agent's constraints, involving marginal substitutions according to changes in prices and income just as in standard choice theory.(...)

Thus, we can model *homo economicus* as following the categorical imperative by incorporating perfect and imperfect duties into his choice framework as constraints and preferences, respectively. Once these have been ‘chosen’ with respect to the agent’s duty, and an ordinal utility function is constructed from them, he will maximize as usual; therefore, Kantian economics agents differ from consequentialist ones not so much in how they optimize, but
*amongst what* they optimize and *how they choose* what to optimize. White (2004, p.98-99)

White's position to reconcile deontological obligations with the utilitarian framework of rational choice may seem convincing as it perfectly fits economic constraints and preferences frameworks, but how does it apply to our example? That is, when choosing between taking your bike or your car to go to work, what perfect duty can you mobilise to infer a self-imposed constraint?<fnref n="9" /> It cannot be 'do not emit carbon emissions' as even the smallest (yet vital) action may emit some; nor can it be 'do not hurt others through your carbon emissions' as taking your car may not cause any trackable harm (Sinnott-Armstrong, 2005; Kingston and Sinnott-Armstrong, 2018)<fnref n="10" />. It shall, thus, take the form of an imperfect duty, depending on one's particular *benevolence* or ecological consciousness; but the question of 'how much' would still be left unanswered or, as Baatz (2014, p.9) puts it, 'What can morality reasonably demand?'

## 2.3 What Responsibility? Responsibility of What?

Dealing with the notion of individual responsibility and self-imposed constraints, formulating the right moral duty may be more thorny than what first meets the eye. On the one hand, to Johnson (2011, p.151) 'In Kantian terminology the obligation to make unilateral reductions is an imperfect duty, meaning that the amount of reduction cannot be specified and is left to the judgment of the individual.' On the other hand, Baatz (2014) emphasizes the difficulty in setting a general and universal threshold of emissions as it largely depends on macroeconomic constraints imposed on heterogeneous agents: he takes the example of an elderly woman in a rural area of the United States, who depends on her car to buy food, who does not have good isolation in her home and lacks the fund to invest in it. Can we, reasonably, impose drastic reductions on her? To Baatz, in addressing the need to reduce our carbon emissions, one needs to consider the macroeconomic constraints they face: high costs of transitioning to low-consuming devices; low elasticity of demand; lack of public infrastructures and public transport. Thus, the level of reduction may depend on an individual and circumstantial basis

<footnote n="9">⁹Granting the protection of the environment an infinite value is quite common, yet heavily discussed (Bartha, 2007; Bartha and DesRoches, 2017; Colyvan et al., 2010; Colyvan and Hájek, 2016; Broome, 2012). There are three main arguments against assigning an infinite or absolute value to the protection of the environment (Colyvan et al., 2010, p.224): 1) it would disable any discrimination between different ecological objectives (for instance, preserving a bee nest would be tantamount to protecting the Antarctic ice sheet as they are both absolute duties). 2) It would swamp probabilities and we could not discriminate two actions, one leading to a 1% chance of destroying a biotop; and the second one a 100% chance of destroying it. 3) From an epistemic perspective, it may seem implausible as people do not really give an infinite value to anything (or else they would be willing to sacrifice anything or have infinite levels of savings in regard to the future.)</footnote>

<footnote n="10">¹⁰Jonas (1985, p.11) defines three possible imperatives to address this new agency: 1) 'Act so that the effects of your action are compatible with the permanence of genuine human-life'; 2) 'Act so that the effects of your action are nor destructive of the future possibility of such life'; or 3) 'Do not compromise the conditions for an indefinite continuation of humanity on earth.' Jonas' ambition is to base the permanence of humane life as an ontological necessity in human action and ethics, we do not see it as a strong objection to our argument: perfect duties are either too strict or too loose to be precisely integrated as constraints in rational choice theory.</footnote>
rather than the universal level. Baatz (2014, p.15) concludes that the degree of 'reasonable' reductions applies if 'an action generating [greenhouse gas] emissions either (a) has no moral weight or (b) an alternative course of action (that is to be considered as an adequate substitute) causing fewer emissions exists.' In this framework, taking your bike or your car may be up to discussion regarding its moral weight; but as the less-polluting alternative exists; then we can infer that we *ought* to take our bike. But if we consider this *ought* as any other preference, then it risks being overruled by other, more polluting, preferences (say the comfort of being in your car).

The concept of ‘Kantian economics’ is therefore relevant to our problem of ecological commitments, but suffers from a consistent discrepancy. On its teleological account, Kantian optimisation offers new grounds for microeconomic cooperation and provides a new perspective to the classic Nash equilibrium in Game Theory. However, it usually assumes a well-defined objective and a loose definition of Kantian Imperatives. On the other hand, its deontological account bridges moral imperatives (considered as endogenous constraints, as opposed to a tax or a political enforcement which would be an exogenous constraint) and the utility maximisation framework. Nevertheless, this deontological account leaves little to no place for evaluational conflicts and infers perfect knowledge of what is right or moral. Our prime example, however, sets a deeper moral problem as we are not sure how to evaluate the two options considering both are justified.

# 3 Rational Choice with Unresolved Valuation Conflicts

Ecological commitments raise questions about how to evaluate different options: which can be judged rational, which can be judged responsible, and upon what criteria. Can they be both rational and responsible if these two notions conflict? The framework of rational choice with unresolved valuation conflicts can be useful in exploring ways of formalising them and addressing theoretical limits from the commitment and Kantian frameworks.

## 3.1 Choice under Normative Uncertainty

Taking your bike rather than your car may be up to several valuation systems (accounting for deontological imperatives, or solely evaluating relevant consequences of outcomes for instance). As such, there may be no clear option that would be 'better' on all different evaluation systems – had we a single valuation metric across all first-order valuation systems. *All things considered*, no one can unequivocally argue that the deontological stance is better nor can they strongly argue for the consequentialist

<footnote n="11">¹¹Baatz also concludes to enhance pressure on legislative and executive bodies to act, on a broader scale, to lower our emission levels.</footnote>
stance: if we adopted a single deontological stance, the choice the agent is facing would be limited to moral duty and would not be up to discussion with economists; on the other hand, if we solely adopted the pursuit of self-interest, we would be too narrow on our definition of what is rational to include ecological behaviours. Having a clear winner would thus imply a strong hermetic relationship between philosophy (and more precisely climate ethics) and economics. To account for both valuation systems, several theories have emerged in the field of 'Choice Under Normative Uncertainty'. We define normative uncertainty as an uncertainty regarding the means of evaluations of different actions: you are unsure what you *ought* to do, and *how* to evaluate alternatives. More precisely, from an axiologic stance, one could recognize that reducing our carbon footprint is the right thing to do but not deduce a normative claim to act accordingly as the consequences born by such actions are negligible. Hence a specific form of normative uncertainty when facing climate-related issues: should I commit to reducing my carbon footprint when I know for a fact that such commitment won't change the issue I am tackling? I will briefly present the several theories introduced in both fields to account for unresolved valuation conflicts.

Philosophers of Choice under Normative Uncertainty (Lockhart, 2000; MacAskill, 2014, 2016; MacAskill et al., 2020; Bykvist, 2014, 2017; Tarsney, 2018, 2019; Greaves and Cotton-Barratt, 2023; Dietrich and Jabarian, 2022) have elaborated several theories to account for such situations:

1. *My Favorite Theory*: In this approach, you attach a credence (which usually stands for a correctness probability, $P_r \in [0,1]$) over different first-order valuation systems, and you only consider the one in which you give the highest probability of being correct. This eliminates any other first-order valuation systems with lower credences. MacAskill et al. (2020, p.67) define it more precisely as 'A is an appropriate option iff A is a permissible option according to the theory that the decision-maker, S, has highest credence in.' This approach can be quite useful in deciding which option has the highest chance of being permissible and thus deduces a rule of action.

2. *Threshold Theory*: The threshold theory relies on a stochastic dominance: 'when an agent A faces a choice between options O and P, where P is certainly morally permissible and the status of O is uncertain, A subjectively ought not choose O if her credence that O is objectively prohibited is greater than or equal to [0.5].' In other words, with a partial ordering of options O and P, you attach a probability ($P_r \in [0,1]$) that O is morally prohibited in all rankings possible; if $P_r(O) > 0.5$, then O is prohibited across all possible rankings' (Tarsney, 2018, p.506). This approach takes the moral problem the other way around and establishes a threshold of credence upon which an action becomes prohibited and thus limits the number of permissible actions.
3. *Expected Choice-Worthiness:* This approach is defined by MacAskill et al. (2020, p.78) as: 'When we can determine the expected choice-worthiness of different options, A is an appropriate option iff A has the maximal expected choice-worthiness.' The notion of choice-worthiness is quite similar to that of expected utility, but the choice-worthiness function may coincide with ethical considerations, financial or material satisfaction, etc., that is, with the values we attach to different options. More precisely, MacAskill and Ord (2020, p.329) defines *choice-worthiness* as 'the strength of the reasons for choosing a given option.' In other words, when faced with several options, the individual attaches some weight to an option depending on the reasons they have to choose it.

We will focus on Expected Choice-Worthiness, as it is the theory the most likely to fit our example of taking your bike rather than your car. In this framework, an individual assigns a cardinal value to the expected choice-worthiness of an option which gives an 'expected choice-worthiness function' that such an individual seeks to maximise. As such, even if your actions might make no difference in the occurrence or the avoidance of an outcome, you still may have some reasons (*or choice-worthiness*) to do so as a way to maximise such a function. This framework has notably been adapted to voting as a possible account of rational choice.

## 3.2 Expected Choice-Worthiness and Voting

In order to assess rational choice in situations when you are unsure what you ought to do, and more specifically in cases where your actions do not matter much (such as voting, but we can easily extend this framework to ecological behaviours such as taking your bike), MacAskill (2016, p.989) argues that a specific form of maximising expected choice-worthiness may apply: the Borda rule. MacAskill defines the Borda rule, applied to choice under normative uncertainty as such:

> An option A's *Borda Score*, for any theory $T_i$, is equal to the number of options within the option-set that are less choice-worthy than A according to $T_i$, minus the number of options within the option-set that are more choice-worthy than A according to $T_i$.

> An option A's *Credence-Weighted Borda Score* is the sum, for all theories $T_i$, of the Borda Score of A according to theory $T_i$ multiplied by the credence that the decision-maker has in theory $T_i$.

> (...) *Borda Rule*[]: An option A is more appropriate than an option B iff A has a higher Credence-Weighted Borda Score than B; A is as appropriate as B iff A and B have an equal Credence-Weighted Borda Score.

In other words, the Borda rule states that you can rank possible candidates (options A, B, C,
etc.)and assign to each one a score to express how closely you feel to one candidate. Suppose that you are unsure about the correct means of evaluation of these two options, so that you attach a credence or *expected degree of correctness* ∈ [0, 1] to Tᵢ in which the total sum of your credence equals 1. To express how closely you feel to taking your bike (consider it to be option A) under a specific theory (Tᵢ, say deontology for instance) you rank it above all other options available. According to MacAskill's definition, you assign it a *Borda score* which assigns a numerical value calculated as such: all the other options ranked below A minus the ones ranked above (here suppose that there is none so A has the highest score possible). Once you have the Bordaje Score, you multiply it by your credence in Tᵢ which gives you the *Credence-Weighted Bordaje Score*; finally the Bordaje Rule states that the more appropriate option is the one with the highest *Credence-Weighted Bordaje Score* which translates to the expected choice-worthiness of A according to Tᵢ. More precisely, the winning candidate is the one with the highest score summed across all voters (or across all first-order valuation theories). Hence, even if under specific first-order valuation theories taking your bike might be dominated, there exist other first-order valuation theories in which it is dominant. Thus, according to the Bordaje Rule, the option with the highest score across every ranking is the one yielding the more expected choice-worthiness and thus the most rational (and moral) option to choose.

Put differently, MacAskill argues that, in cases of normative uncertainty, you may still rank different
options upon different first-order valuation theories (for instance, if you adopt a consequentialist valu-
ation theory, you may rank taking your car (x) above taking your bike (y), and the other way around if
you adopt a deontic valuation theory; but you may also be able to tell *how much* these two options are
distant to one another) and thus aggregate the value (the *score* you assigned each candidate) across
all the possible rankings, which will give you a rule of action. According to MacAskill, relying on the
Borda Rule and voting theory is a way to bypass intertheoretic incomparability (saying that a conse-
quentialist choice-worthiness and a deontic one are incomparable) and the problem of merely ordinal
theories (saying that inside a given theory, one cannot ordinally rank *all* alternatives): 'We therefore
have a principled metanormative theory that is far more general than simply maximizing expected
choice-worthiness.' MacAskill (2016, p.1000). Yet, such a conception of maximising expected-choice
worthiness as a Bordaje rule implies strong methodological postulates. MacAskill (2016, p.972) assumes
that 'each theory in which you have credence needs to provide a concept of choice-worthiness that is at
least interval-scale measurable. (...). Second, you need to be able to make comparisons of magnitudes
of choice-worthiness across different moral theories.' To be interval-scale measurable means that you
can tell the wrongness of a genocide far exceeds that of a lie (so MacAskill's argument goes), but
that of a theft is much closer to the wrongness of a lie. In other words, interval-scale measurability
infers that you can gradually tell the difference between several options and thus necessarily infers
comparability of cardinal values across different first-order valuation theories, hence the 'comparisons
of magnitudes of choice-worthiness across different moral theories.

As the Borda Rule applied to normative uncertainty relies on the aggregated sum of Credence-
Weighted Borda Scores, it implies that the cardinal values at stake need to be meaningfully comparable
across moral theories. In other words, it implies that we can meaningfully<sup>12</sup> compare the wrongness
of taking your car according to a Kantian framework to the righteousness of taking it according
to hedonistic consequentialism. Such a postulate seems quite disputable, as Tarsney (2019, p.1288)
argues ' the Borda rule amounts to an implicit "cardinalization" of ordinal rankings and therefore
does not fully come to grips with the problem of merely ordinal theories.' One could argue that there
is something deeply incommensurable between the characterisation of rightful and wrong doings in
climate ethics.

## 3.3 Hard Choices

Indeed, another way of conceptualizing ecological commitments as an unresolved valuation conflict
is to consider it as a hard choice. A hard choice is when 'neither seems to be at least as good as the
other overall, that is, in all relevant respects' Chang (2017, p.1). Thus, unlike choice under normative
uncertainty, which focuses on elucidating the permissible criterion of evaluation to use, hard choices
are 'hard' insofar as no option is clearly ranked above, below or a par with the others. Ecological
commitments constitute hard choices in which several dimensions of value are non-commensurable to
one another, whether these dimensions may be in conflict or not. The source of difficulty of these
choices may be 'deliberatively hard' (Tenenbaum, 2024)<sup>13</sup>, that is they regard evaluative difficulties in
elucidating which option is slightly better or worse despite their indeterminacy; or they can be 'hard'
because they are on a par, *i.e* they are both rational to choose and morally permissible, but because
they engage 'a volitional activity of putting your very self behind something' (Chang, 2024, p.283).
According to Chang, 'it is the difficulty of getting your *very self* to take one normative direction rather
than another when the usual resources of rational agency – reasons or values – do not instruct you in
the matter' that constitute the distinctive hardness of certain choices. Despite being both rational and
responsible, according to incommensurable moral theories, an agent may still choose an alternative
rather than the other one in doing what Chang coins as 'commitments'. In Chang's account of hard
choices, an agent may commit to a particular choice as a way to normatively engage their identity (your

<footnote n="12"><sup>12</sup>By meaningfully we understand ‘capable of deducing reasons strong enough to determine one’s action.</footnote>

<footnote n="13"><sup>13</sup>Tenebaum defines a deliberative hard choice as a choice which gives no clear answer, even after elucidation of all the relevant deontic status of all available options.</footnote>
‘very self’). Commitment, in cases of hard choices, is ‘taking charge in creating values for yourself in the face of an open sea of reasons and values’ (Chang, 2024, p.283). Thus, one could argue that when deciding between taking your bike or your car to go to work, it is equally rational for them to choose both options, *i.e* there exists no more rational nor more responsible answer across all first-order theories, but the agent can make it the *right* answer through their commitment. In other words, the agent does not take their bike because it is the most rational or responsible option, but because they commit themselves to having more reasons to take their bike rather than their car. In the context of hard choices, commitments refer to the agent’s exercise of normative power to create reasons apt to justify choosing one alternative over another.

As a bridge of the three frameworks mentioned, Sen (2004) has focused on the issues of incom-
mensurability and maximisation when dealing with hard choices. His main ambition is to criticize the
idea that, in order to get a maximizing framework, you need a complete ordering between different
options which ought to be comparable. The more implicit critique of decision theories is the postulate
that ‘there must be ultimately one source of significance (...) in order to choose rationally.’ (Sen,
2004, p.45). Sen (2004, p.47) takes Levi (1986)’s V-admissibility criterion to resolve hard choices. The
V-admissible options are a non-empty set of options “that have not been prohibited by the agent’s
value commitment from being chosen by the agent.” With a progressive tightening of the admissibility
of these options (and thus progressive exclusion of inadmissible alternatives), Sen and Levi argue that
it may offer a resolution of hard choices. But even if incompleteness persists after such a tightening,
and may never reach ‘completion’, without being problematic to rational choice theory. Sen (2004,
p.56) concludes ‘The recognition that incompleteness of judgments can be a constituent part of the
definite conclusions advanced by a complete theory’. Such a conclusion echoes Chang’s conception
of commitments: if we are to comprehend ecological commitments as both rational and responsible,
both of these theories may remain partially incomplete and incommensurable to one another. Indi-
vidual commitments constitute the agent’s capacity to determine their own reasons for action. RCT
implies having *one* optimal (or most rational) option among alternatives, but climate ethics involve
incommensurable values at stake which may never completely be perfectly ordinal; thus, ecological
commitment may not be the most rational option across every first-order valuation theories but the
agent may still have the normative power to make it come true. Thus, ecological commitments can be
both rational and subject to deontological considerations.
# 4 Relevance

The main relevance of this analysis of different frameworks incorporating deontological motives in RCT is to analytically ground individual commitments without relying on political enforcement or monetary incentives. This aim is deeply rooted in Kantian autonomy, as Etzioni (1987, p.44) states 'rules and institutions cannot rest on deterrence because there are not enough policemen (...) rules and institutions hence must rely, to a significant extent, on internalized moral commitments.' Enhancing the structure of Rational Choice so as to accommodate volitional ecological commitments is a way bypass dead-ends posed by monetary incentives policies.

On the methodological scope, this paper accounts for several strengths and weaknesses across three frameworks which are aligned yet do not seem to be permeable to one another. While they all share the same common ground (accounting for both rational choice theory and moral imperatives), they do not really constitute a unified literature. This paper highlights both their interconnection and their own limitations.

As such, on the normative scope, an enhanced understanding of rational choice and individual responsibility may allow to broaden and refine models of carbon taxation, or public policies which would be sub-optimal otherwise. Bazin et al. (2004); Ballet et al. (2007) argue that, upon a certain threshold, the introduction of a carbon tax induces a crowding-out effect of individual responsibility and thus lead to a degradation of the environment's quality. Mattauch et al. (2022) argues that carbon taxes and public policy, in general, do modify the agent's preferences and, if not accounted for, would lead to sub-optimal levels of taxation. Hartmann et al. (2023, p.1) argues that 'awareness of paying a carbon tax could trigger a moral licensing process that interferes with its demand-reducing effect.' To them, hidden carbon taxes outperform (in reducing the demand) salient ones insofar as they do not contribute to the moral licensing of the consumer. Kaufmann et al. (2024) argue that 'socially responsible consumers' may false the impact of carbon taxes and thus lead to overconsumption of polluting goods. Note that Kaufmann et al. (2024)'s conception of responsibility ('being willing to modify one's consumption to mitigate the associated externality' (Kaufmann et al., 2024, p.1997)) is quite similar to the one we adopted. All these contributions point out to the same argument: if we do not account for individual responsibility at stake in climate-related issues, many public policies such as carbon taxation may remain sub-optimal.

# 5 Conclusion

This paper provides new perspectives on ecological behaviours by integrating them in three frameworks of rational choice. We discussed Sen's notion of commitment; Kant's perfect and imperfect duties
and unresolved evaluational conflicts. Our analysis of these three frameworks challenges rational choice theory by demonstrating that ecological behaviours can never be reduced to enhanced other-regarding preferences, nor can they be the result of moral duties which highlights an unresolved valuation conflict. Instead, ecological behaviours necessitate a redefinition of individual ecological responsibility at stake in climate-related issues. By comparing both utilitarian and deontological perspectives and their permeability, this paper provides a novel framework for understanding ecological responsibility as an interplay of individual commitment, moral obligations, and maximisation of choice-worthiness. Such a conception of moral responsibility has broader implications: it challenges the assumption of an economic agent inconsiderate of climate issues. Such a notion of responsibility calls for a deeper understanding of the roles of preferences in models of carbon taxation, financial offsetting, and more broadly in the debates on downstream responsibility (i.e consumer's responsibility).

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