Why Do We Punish: Theories Behind Criminal Sentencing

Let us suppose that a person commits a murder. This person is to be tried in two different courts in different countries on the same charge. One court sentences him to death and the other sentences him to life imprisonment and provide compensation. Why?

This difference between the two courts lies in what we call theories of punishment. While there are universally agreed upon principles as to the purpose of punishment, there are different schools of thought, possessing unique reasoning as proportionality of the crime to its punishment, duration of punishment, type of punishment and more.  

In this post, we broadly cover the varying schools of thought of punishment, where they originated from, and real-world examples of punishment given by judiciaries following the said school of thought.

1. Retributive Theory – An Eye for an Eye and Nothing More

• The idea that wrongdoers deserve to be punished; not because it reforms them, not because it deters others, but simply for the reason because justice demands it, is the oldest and most instinctive response to crime for society. 
• The foundation for this arose from the philosopher Immanuel Kant who wrote in his work The Metaphysics of Morals that punishment was not a tool for achieving social outcomes, but rather a moral imperative. When a person commits a crime, they violate society’s moral order and the idea of justice requires that society provides a proportional response.
• Kant drew a sharp line between retribution and revenge; revenge is personal, emotional and unconstrained while retribution is principled, proportional and owed to society as a matter of right. 
• In India, this theory was brought through the colonial transplantation of English criminal law. The Indian Penal Code, 1860 awarded the capital punishment in crimes such as murder, proving a retributive nature. 
• Post-independence, Indian courts began grappling more openly with the why of punishment, particularly in death penalty cases where the stakes demanded justification beyond mere statutory authority, like the case of Bachan Singh v. State of Punjab.
• In this case, Supreme Court’s five-judge constitutional bench decision remains the most important Indian pronouncement on punishment philosophy. While the Court ultimately upheld the constitutionality of capital punishment, what is significant is how it reasoned. The Court explicitly surveyed retributive, deterrent and reformative theories, declining to anchor sentencing in any single theory while also  acknowledging retribution’s legitimate place within a balanced framework. The “rarest of rare” doctrine that emerged from the case is itself a retributive proportionality principle; it reserves the ultimate punishment for crimes of ultimate culpability, insisting that the sentence must be commensurate with the moral gravity of the act.

2. Deterrence Theory – Cost of Consequence

• The premise of deterrence is simpler and more coldly rational than retribution: punishment exists not because the offender deserves it but because the threat of it stops people from offending in the first place. It is forward-looking where retribution is backward-looking since it is less concerned with answering past wrong than with preventing future harm.
• While Cesare Beccaria was the first to provide this idea, it was actually Jeremy Bentham who gave deterrence its utilitarian philosophical support as he believed that human beings are rational actors who weigh pleasure against pain. Excess punishment is itself an injustice because it serves no additional deterrent purpose, believed Bentham.
• Deterrence entered Indian criminal law thinking through the same colonial channel as retribution: the IPC, but it found its most explicit expression not in the Code’s structure but in judicial reasoning, particularly in cases involving crimes that provoked widespread public outrage.
• The most significant modern illustration is the judicial and legislative response to the Nirbhaya gang rape case. The brutal nature of the offence and the public outcry that followed produced two distinct deterrence-driven responses. The first was legislative with the Criminal Law (Amendment) Act, 2013 enhancing penalties for sexual offences and the second being legislative intent: Parliament was using enhanced punishment to show that the consequence of sexual violence would be extreme.
• The second was judicial by way of Mukesh v. State (NCT of Delhi) where the Supreme Court, while confirming the death sentences of the convicts, engaged directly with deterrence as a justification, reasoning that the collective conscience of society demanded a response that would serve as a warning that crimes of such depravity would be met with the ultimate penalty. It also highlighted a tension: offenders in the heat of the moment, intoxicated or desperate rarely pause to calculate penal consequences.

3. Rehabilitative Theory – Punish the Crime & Reform the Criminal

• If retribution looks backward and deterrence looks outward, rehabilitation looks inward: at the offender themselves.
• The philosophical groundwork for this shift was laid by Enrico Ferri, the Italian criminologist who argued that crime is not purely a product of free moral choice but is shaped by biological, social, and environmental factors beyond the individual’s complete control. If the causes of crime are external or systemic, punishment that merely inflicts suffering without addressing those causes is not only ineffective but irrational. 
• This thinking gained significant institutional traction through the 20th century, manifesting in probation systems, open prisons, parole frameworks and eventually juvenile justice legislation, all built on the premise that the offender can and should be returned to society as a functional, law-abiding member.
• Legislations like the Probation of Offenders Act, 1958 is an embodiment of rehabilitative philosophy that empowers courts to release first-time and minor offenders on probation rather than sentencing them to imprisonment, premised on the idea that incarceration for such offenders may do more harm than good by exposing them to hardened criminals and disrupting their rehabilitation. 
• The Supreme Court’s decision in Rama Murthy v. State of Karnataka is the most comprehensive judicial treatment of imprisonment and reformation where it was held that imprisonment must serve the reformative purpose the law intends by issuing directions on prison reform covering legal aid, classification of prisoners and rehabilitation programmes, grounded in Article 21’s guarantee of dignity. Crucially, the Court insisted that Article 21 is not suspended upon conviction, and any system treating incarceration as mere warehousing fails both the constitutional standard and the reformative purpose that justifies imprisonment. Rehabilitation, as per the Court, is not a concession to the offender but what gives the deprivation of liberty its legal and moral legitimacy.

4. Incapacitation Theory – Remove the Threat to Protect Society

• Unlike the theories discussed so far, incapacitation does not ask what the offender deserves, what message punishment sends, or whether the offender can be reformed but rather asks a single, blunt question: how do we stop this person from offending again? The answer is equally blunt; remove them from society for as long as the risk they pose justifies it.
• Incapacitation draws from two intellectual streams: The first is an older, instinctive logic rooted in early penal practices of banishment, exile, and transportation, and the second is the utilitarian tradition which states that if punishment exists to maximise social welfare, isolating dangerous offenders is justified simply because it prevents harm to the many. 
• India’s legal framework reflects incapacitative logic in two distinct ways: through conventional sentencing and through preventive detention legislation.
• In conventional sentencing, incapacitation appears most clearly in death penalty jurisprudence following Bachan Singh, where the Supreme Court has in several cases confirmed capital punishment or life imprisonment on the explicit ground that the accused poses an irredeemable and continuing danger to society. 
• The more constitutionally contentious expression is India’s preventive detention framework. Statutes such as the National Security Act, 1980 and the Unlawful Activities (Prevention) Act permit detention not as a response to a crime already committed but as a precautionary measure against anticipated future harm. The logic is purely incapacitative as the individual has not been convicted, yet their liberty is curtailed because the state deems them a sufficient threat.
• In the case of Kartar Singh v. State of Punjab, the Supreme Court upheld the constitutional validity of The Terrorist and Disruptive Activities (Prevention) Act, while reading into it certain procedural safeguards. The Court accepted that where the threat posed by an individual is systemic and organised, conventional punitive responses are insufficient and incapacitative measures become necessary, thereby justifying stricter bail conditions, longer detention periods, and special tribunals. Crucially however, the Court held that even incapacitative detention cannot be arbitrary, and procedural fairness remains a constitutional floor below which the state cannot descend.

5. Denunciation Theory – Society Speaks

• Denunciation theory operates on the premise is that punishment is society’s formal, public condemnation of the offender’s act. The sentence is primarily about society collectively declaring through the machinery of the state that certain behaviours or actions are fundamentally unacceptable.
• Its sociological foundation lies in the work of Émile Durkheim, who argued in the late 19th century that crime is not merely a violation of individual rights but an assault on the collective conscience, i.e. the shared moral values that bind society together. Punishment, for Durkheim, is society’s instinctive reaffirmation of those values. It is an expressive act as much as a practical one.
• Indian courts have long employed denunciatory reasoning without always naming it as such. The signs are in the judge’s language; when a court speaks of the “collective conscience of society”, the “shock to the moral fabric of the nation”, or the need for punishment to reflect “the response of a civilised society”, it is articulating denunciation theory. The sentence, in this framing, is not merely a legal outcome but a moral statement.
• Nowhere is this more evident than in the Supreme Court’s handling of Mukesh v. State (NCT of Delhi) aka the Nirbhaya case. Under deterrence theory, the Court invoked punishment as a warning to potential offenders. But the same judgment simultaneously operates on denunciatory logic. The Court’s repeated references to the collective conscience of society, its characterisation of the offence as one that shook the nation’s moral foundation and its conclusion that anything short of the death penalty would be an inadequate response to the gravity of the wrong was all denunciation theory at work. The punishment was not just a deterrent signal or a proportional desert; it was a declaration by society, through its highest court, that the conduct of the accused was beneath the threshold of what a civilised community can tolerate.

When Theories Collide, There’s No Single Answer

• Understanding each theory in isolation is the starting point, but the more honest and more interesting observation is that no legal system in the world operates on a single theory of punishment, and the tensions between them are not incidental: they are built into sentencing itself.
• Consider a straightforward illustration. A first-time offender, young with no criminal history, is convicted of a non-violent drug offence. A retributivist asks: what does proportionality demand? Likely a modest sentence, commensurate with the gravity of the act. A rehabilitationist asks: what does this person need? Possibly treatment and not imprisonment at all. A deterrence theorist asks: what sentence sends the right signal to others? Perhaps something harsher than pure imprisonment would justify. An incapacitation theorist asks: what is the risk of them reoffending? If low, perhaps minimal intervention. A denunciation theorist asks: what does society need to say about this conduct? The answers pull in different directions and the sentencing judge must navigate all of them simultaneously.
• This is not a flaw in the system but is rather a reflection of the fact that punishment is, at bottom, a moral question dressed in legal clothing, and that moral questions rarely yield clean, universal answers.

Conclusion

• The theories surveyed in this piece: retribution, deterrence, rehabilitation, incapacitation and denunciation are not competing candidates from which one must be chosen but rather lenses, with each illuminating a different dimension of why we punish and what we hope punishment achieves: a mature legal system developing mature legal minds that hold all of them in tension rather than collapsing into the comfort of a single framework.
• The practical value of understanding these theories lies in recognising which one a court is implicitly drawing upon at any given moment, in a sentencing submission, a bail argument, a parole hearing or a policy debate. The language judges use is rarely philosophically labelled but it is almost always theoretically grounded.
• The deeper question, of what punishment is ultimately for, will always remain open. Every legal system’s answer reveals something about the values of the society it serves, which is something worth sitting with.