The French penal ordinance of 1670 set out very harsh penalties, but a gap existed between theory and penal practice. Public execution and torture were not the most frequent form of punishment. However, torture played a considerable part in penality. The definition of torture involves an exact, measurable quantity of pain. An "economy of power" is invested in torture.

Torture is part of a ceremony that reveals the truth of a crime. The trial is initially a hidden process. But a tradition of rules of evidence existed: there were different degrees of proof. Now these degrees relate to the juridical effects or the outcome of the trial. Penal investigation was written, secret and subject to rules. It was a machine that might produce the truth in the absence of the accused. But a confession removed the need for further investigation. A confession transforms an investigation from a process carried on against the criminal to a voluntary affirmation. The ambiguity of the confession explains the means used to obtain it: the oath and judicial torture.

Torture is an ancient practice, which had a strict place in the classical legal system. It had two elements: a secret investigation by judicial authority and a ritual act by the accused. The body of the accused linked these two elements. This is why, until the whole classical system of punishment was examined, there was no critique of torture. Judicial torture was a regulated practice, almost a game. If the suspect successfully resisted, he could be freed. Classical torture was a way of finding evidence in which investigation and punishment were mixed. As the system of proof produced a partial proof of guilt, torture punished this partial guiltiness whilst investigating it further.

In the execution, the criminal's body showed the truth of his crime because, one) the criminal became the herald of his own condemnation; two) it took up the scene of confession, where the full truth was revealed; three) it pinned public torture onto the crime itself; four) its slowness and suffering became the ultimate proof at the end of the ritual. From judicial torture to execution, the body produces and reproduces the truth of the crime. A public execution is to be understood as a political as well as a judicial ritual. The intervention of the sovereign in a case was a reply to an offense against him. Public execution was a ritual by which injured sovereignty was restored. Public execution was a ritual of armed law with two aspects: victory and struggle. The conflict and triumph of the executioner over the body of the accused was like a challenge or a joust.

Attitudes toward punishment were related to general attitudes to the body and death. Death was familiar because of epidemics and wars. These general reasons explain the possibility and long survival of physical punishment. Torture was embedded in legal practice because it revealed the truth and showed the workings of power though the body of the condemned. This truth-power relation remains at the heart of all mechanisms of punishment, and is found in different forms in contemporary penal practice. The Enlightenment condemned the "atrocity" of public execution. Atrocity is the part of crime that torture turns back on itself to display the truth of crime to the world. The mechanism of atrocity mixed the sovereign and crime together; atrocity was the "organized destruction of infamy by omnipotence."

One reason why a punishment that was unafraid of atrocity was replaced by a "humane" version is very important. A key element in the execution was the people or audience. But the role of the people was ambiguous. Criminals often had to be protected from the crowd, and crowds often tried to free prisoners. The intervention of the crowd in executions posed a political problem. In his last words, the convict could, and did, say anything. Uncertainty exists over these last words: were they fictitious? Perhaps crime literature was neither "popular expression" nor moralizing propaganda but the space in which the two investigations of penal practice met.