Punishment needed for deterrence

 Rambam (Moreh Nevuchim 3:41): Concerning the punishment of those who sin against others, the general rule is that it should be done to him exactly as he has done to the other person. If he damaged the other person’s body then he should be punished physically. If he caused monetary damage he should pay for it with money. However the one who suffered monetary damage should be ready to forgive and be lenient. It is only in the case of murder that we are not lenient at all and we don’t take a monetary payment for the crime.  Therefore even if the victim of the attack lived for an hour or days and was able to speak and he requested that his assailant be forgiven because he had forgiven him – we don’t listen to him. We are required to take life for life and there is no distinction made whether it is the life of a child or an adult, a slave or a free man, a scholar or a fool – because there is no greater sin than this. If someone caused the loss of a limb then he must be punished with the loss of his limb. Vayikra (24:20) says, As he has caused a blemish in a man so shall it be done to him. Don’t be bothered by the fact that this is never done but rather a monetary penalty is always imposed. Our purpose in this composition is only to give the reason for the Torah verses and not the reason for the Talmudic practice. Nevertheless I have what to say regarding the view of the Talmud but will only communicate it in private. Those injuries which can not be done exactly to the assailant as he did to his victim are compensated by monetary payment as it says (Shemos 21:19), “Only he shall pay for the loss of his time and full payment for medical expenses. Someone who has damaged another’s property should pay back exactly the monetary amount that he damaged. An important principle is that to the degree that a sin or transgression is more frequent and more probable to be committed – the more severe must the punishment be in order to serve as a deterrent. In contrast that which rarely occurs receives a lighter punishment. … There is a basic principle that the greatness of the punishment and how painful it is depends on the following four factors. 1) The enormity of the sin. Those actions which bring about great loss have severe punishments, while those actions which produce little harm have minor punishments. 2) The frequency the crime occurs. Those crimes which happen more often need to have more severe punishments to deter them. In contrast to the degree that a crime is rare to that degree the punishment is reduced because that is sufficient to deter it. 3) The degree of temptation. A crime of great temptation – either because the lust for it is great or people are accustomed to do it or the crime causes a great reduction pain – then it is obvious that there will be no deterrence unless there is a fear of severe punishment. 4). The ease of doing the crime secretly and hidden from detection and unnoticed by others. Deterring such acts can only be done by fear of a great and severe punishment…