The central issue concerns what is meant by pleasure, and crucially, whose pleasure is considered in assessing the morality of sexual acts. Pleasure could be defined narrowly as physical or sensual gratification, or more broadly as psychological, emotional, or spiritual fulfilment — the flourishing of persons through mutual respect and love. Different ethical theories draw the circle of concern differently: some include only the immediate participants, while others consider the wider social and moral consequences. Utilitarianism and Natural Law both offer frameworks that could, in broad terms, agree that pleasure is relevant to moral judgment — though they interpret pleasure and goodness in distinct ways. Kantian Ethics, by contrast, challenges the idea that pleasure, or any consequence, can determine moral worth at all. This essay will argue that the amount of pleasure produced is the most important factor determining whether a sexual act is right, when pleasure is understood as contributing to human flourishing and the circle of ethical concern is drawn widely.
Utilitarianism supports the idea that the moral rightness of an action depends on the pleasure or happiness it produces, making it an ethical theory that aligns closely with the statement. Jeremy Bentham’s classical act utilitarianism defines the good in quantitative terms: the right act is that which produces “the greatest happiness for the greatest number.” For Bentham, pleasure and pain are the only measures of value, so a sexual act would be right if it maximizes pleasure and minimizes harm for all affected. John Stuart Mill, developing the theory, refined this by distinguishing higher and lower pleasures — suggesting that not all pleasures are equal, and that those associated with intellect, love, and moral sentiment are superior to mere physical gratification. In evaluating sexual ethics, Bentham’s approach would justify consensual sexual relationships of any form, provided they increase overall happiness and harm no one. For instance, non-traditional sexual relationships or same-sex partnerships could be defended under utilitarian reasoning, if they lead to mutual pleasure and well-being without causing wider social or personal harm. Mill’s perspective would affirm sexual acts that express love, mutual respect, and psychological depth as contributing to higher forms of pleasure — thus aligning morality with the quality of human relationships rather than with biological function or social convention. Utilitarianism’s strength lies in its flexibility and inclusivity. It allows moral evaluation to evolve alongside human understanding of sexuality, consent, and well-being. This makes it particularly compatible with contemporary ethical discourse, which emphasizes consent, equality, and emotional health. However, critics argue that pure hedonistic utilitarianism risks justifying exploitative or objectifying sexual acts if they produce more pleasure overall — for example, if the pain of a few is outweighed by the pleasure of many. Mill’s qualitative refinement addresses this by grounding moral pleasure in human dignity and rationality, not mere sensation. While utilitarianism’s focus on pleasure aligns strongly with the essay’s claim, it must be understood in Mill’s enriched sense — as contributing to overall human flourishing. If pleasure is interpreted this way, utilitarianism demonstrates that the amount of pleasure produced is the most important factor in determining whether a sexual act is right, if pleasure includes psychological and relational well-being, and is balanced against potential harm. Thus, utilitarianism supports the thesis when pleasure is defined broadly and the moral circle includes all those affected — showing that pleasure, properly understood, remains central to moral judgment in sexual ethics.
Natural Law, though seemingly at odds with a hedonistic view, can also support the claim when pleasure is defined as the flourishing of human beings through the fulfilment of their natural purposes. Thomas Aquinas’ Natural Law theory holds that moral acts are those that align with the purposes (telos) built into human nature by God. The primary precepts — including the preservation of life, reproduction, and the nurturing of social order — guide moral reasoning. Sexual acts, in this view, are good when they contribute to both procreation and the union of persons in mutual love. While pleasure is not the ultimate good, it is a secondary good — a natural consequence of rightly ordered sexual relations that foster human flourishing. Aquinas explicitly acknowledges that sexual pleasure is not sinful in itself; rather, it becomes wrong when detached from its rightful context — marriage and the potential for procreation and unity. For example, within marriage, sexual pleasure strengthens the bond between spouses and encourages familial stability, fulfilling both biological and relational purposes. Modern Natural Law theorists such as John Finnis reinterpret these ideas less biologically and more relationally, focusing on “friendship” and “marital good” as intrinsic goods that promote the flourishing of persons. When pleasure is seen as a sign of human flourishing rather than mere sensation, Natural Law aligns with the view that pleasure is a moral indicator. A sexual act that is selfish, manipulative, or contrary to the integrity of the person fails to promote true pleasure, as it undermines the good of the participants. Thus, Natural Law and utilitarianism converge when the concept of pleasure is widened from bodily gratification to holistic well-being. Yet, some critics might object that Natural Law’s restrictive stance on non-procreative sex limits the scope of legitimate pleasure, potentially excluding many consensual and loving relationships that do promote flourishing. Despite these limits, the Natural Law approach supports the thesis insofar as it recognizes pleasure as a natural component of right sexual acts — evidence of human flourishing when ordered toward love and unity. When “pleasure” is thus redefined in line with human purpose, it becomes a key measure of moral goodness. Therefore, in Natural Law as in utilitarianism, pleasure remains a vital moral factor — not as mere hedonism, but as an expression of ordered human flourishing. When this is the definition applied, pleasure is indeed the most important factor in determining the rightness of a sexual act.
By contrast, Kantian Ethics fundamentally rejects the idea that pleasure — or any consequence at all — can determine the moral rightness of an action. Immanuel Kant’s deontological ethics insists that moral acts must be done from duty, in accordance with the command of reason (known as the categorical imperative), rather than from inclination or desire. The Formula of Humanity states that one should “act so that you treat humanity, whether in your own person or another, always as an end and never merely as a means.” Sexual acts motivated by pleasure risk reducing a person to a means of satisfaction rather than respecting them as an autonomous moral agent. For Kant, sexuality presents a moral danger precisely because it tempts individuals to objectify others. In his Lectures on Ethics, he describes sexual desire as one that “makes of the loved person an object of appetite,” comparing them to a lemon that has been squeezed and then thrown away. Thus, even consensual sexual pleasure must, for Kant, be morally constrained by the institution of marriage, where reciprocal respect and mutual obligation can preserve personhood. However, Kant also acknowledged the problem with ignoring pleasure as a moral factor when he accepted that human beings naturally seek to maximise pleasure and minimise pain. It is not rational to ask people to act against their own natures, so the categorical imperative must include the desire to establish a “kingdom of ends” in which people will be happy and flourish. In his late essay Towards Perpetual Peace, Kant rooted his ethic in the concept of the Summum Bonum — the highest good — in which virtue and happiness ultimately coincide. While he warned that people should not be directly motivated by the desire to produce the Summum Bonum, the hope that it will be realised through rational duty gives moral action its final coherence. It follows that the likelihood of a sexual act contributing to the Summum Bonum, when measured by its consistency with reason and the categorical imperative, is the only factor determining whether it is right, even for Kant. Though Kant explicitly warned against using sex merely for pleasure, his challenge ultimately reinforces rather than undermines the thesis: when pleasure is redefined as the flourishing of persons in respectful, rational relationships, it remains central to moral rightness.
In conclusion, the amount of pleasure produced is indeed the most important factor determining whether a sexual act is right, but only when pleasure is defined in terms of human flourishing and the circle of ethical concern is drawn widely. Both Utilitarianism and Natural Law demonstrate that pleasure — understood as psychological, relational, and moral well-being — is integral to assessing sexual ethics. Although Kantian Ethics reminds us to respect human dignity and resist treating others merely as means, this very respect deepens our understanding of pleasure as shared flourishing rather than selfish gratification. The best reason to adopt this integrated view is that it unites emotion and reason, acknowledging pleasure not as the enemy of morality but as its expression in human happiness.