Theories of justice 

Every legal argument eventually meets a question the earlier articles in this module deliberately set aside: even where a rule is validly law, is it a just rule, and is the outcome it produces a just outcome? This article surveys three influential ways of answering that question and shows how each shows up in legal reasoning.

Why justice is a separate question

Legal positivism, discussed earlier in this module, insists that a rule can be valid law regardless of whether it is just. That separation is useful for identifying what the law is, but it does not answer a question students and courts still have to confront: what should the law aim to achieve, and how should we judge whether it succeeds? Theories of justice supply competing answers, and understanding the main ones lets you recognise — and make — justice arguments precisely, instead of gesturing vaguely at "fairness."

A rights-based approach

A rights-based, or deontological, approach treats certain individual entitlements — to bodily autonomy, to a fair hearing, to be treated as an end and not merely a means — as constraints on what may be done to a person, regardless of the overall benefit that might result. On this view, an outcome is unjust if it violates a person's rights, even if it produces a better result overall. This approach underpins much of the language of legal reasoning around fundamental rights, natural justice and procedural fairness: the idea that some protections are owed to an individual simply because of who they are, not because respecting them happens to maximise welfare.

A consequentialist approach

A consequentialist, or utilitarian, approach judges an outcome, a rule, or a decision by its consequences — typically, by whether it maximises overall welfare or minimises overall harm, aggregated across everyone affected. On this view, a rule is justified because, on balance, it produces better outcomes than the alternatives, even if it disadvantages some individuals along the way. Consequentialist reasoning is common in legal policy debate: arguments about deterrence in sentencing, about the economic efficiency of a regulatory rule, or about the net social benefit of a legislative reform are all, at bottom, consequentialist arguments about justice.

Distributive justice

A third family of theories asks not just whether an outcome is good in aggregate, but how the benefits and burdens of social life are distributed among people. The best-known modern account, associated with John Rawls, asks what principles of justice people would agree to from a position of fairness in which no one knows their own place in society in advance — their wealth, talents, or social position. Reasoning from that position, the theory argues for principles that secure equal basic liberties for everyone and permit social and economic inequalities only where they work to the benefit of the least advantaged. Distributive justice approaches like this focus legal argument on how a rule allocates opportunities, resources, or protections across a community, not merely on individual rights or aggregate welfare.

How these arguments surface in legal reasoning

These three approaches rarely appear labelled as such in a judgment or a problem answer, but they are doing real work whenever an argument moves beyond "what does the rule say" to "why should the rule be this way" or "is this outcome fair." A submission that a particular applicant's rights should not be sacrificed for administrative convenience is a rights-based argument. A submission that a sentencing outcome should reflect its deterrent effect on the wider community is a consequentialist argument. A submission that a regulatory scheme unfairly burdens an already disadvantaged group is a distributive-justice argument. Being able to name which kind of justice argument you are making — and to recognise that a well-prepared opponent may be making a different kind — is what separates a vague appeal to fairness from a structured piece of legal reasoning.

Applying this in a problem question

1. When a problem invites an argument about fairness or justice, identify which of the three approaches you are using — rights-based, consequentialist, or distributive — rather than blending them without acknowledgment.
2. Test a consequentialist argument by asking whose welfare is being counted and over what timeframe; test a rights-based argument by identifying precisely which right is at stake and why it should not be outweighed.
3. Where a distributive-justice argument is available, identify who bears the burden of a rule or outcome and who benefits, not just whether the aggregate result looks acceptable.
4. Anticipate the counterargument from a different theory of justice — a strong answer acknowledges that a rights-based and a consequentialist analysis can point in different directions, and explains why one should prevail here.