In ethical subjectivism moral values are dependent on a will, human or divine, a willing subject. If the will is human, then one has the basis for modern moral relativism, in which humans together (e.g., a legislature) decide what is right and wrong. If the will is divine, then one has a divine command theory of ethics. In this view moral law is a freely chosen creation of God. In cases of infractions against this law, God can freely choose to mete out punishment or no punishment; or, as in the mystery religions and Christianity, God or his agent can decide to take the punishment upon himself. Those who violate the law are still sinners, but God can grant grace and forgiveness for wrong doings. It seems, then, that any doctrine of grace or forgiveness must have its basis in this form of ethical subjectivism.
The three great savior religions of the world-Christianity, the religion of Krishna, and Pure Land Buddhism--grew out of a reaction to various forms of ethical objectivism. Each of them developed doctrines of grace in which the savior infused his grace so that the effects of sin would be removed. People of course would still sin and be apart from God, but the final consequences (death or karmic rebirth) would be eliminated.
The great success and popularity of the savior religions tell us something significant. A great majority of people outside of the priestly or monastic class realized (either consciously or unconsciously) that they could not conform to the moral law without divine aid. The savior religions had a great liberating effect in that all people were equal before God. The savior religions had mass appeal, cutting, as they did, across all classes. As a result they had profound social and political impact.
Ethical subjectivism in the history of Christianity has sometimes been called Divine Command Theory (DCT). This means that whatever God commands is right and whatever God prohibits is wrong. The late medieval philosophy William of Ockham (14th Century) claimed that God could command us to hate him or even kill someone. The Protestant Reformers Martin Luther and John Calvin (16th Century) were influenced by Ockham's students and saw Divine Command Theory as a way to protect the absolute freedom and sovereignty of God. Luther made an exception for the Ten Commandments, but Calvin believed that God had the freedom to do anything short of logical contradiction. (For example, God could not damn everyone and save everyone at the same time.) Christians who support DCT argue that their theory is the only way to protect God from criticism when God commands Abraham to kill his son Isaac (Gen. 22) or when God empowers Satan to kill all of Job's sons and daughters (See the biblical Story of Job).
Note: Despite the argument above many Hindus, Buddhists, and Christians still believe in ethical objectivism or ethical absolutism. They believe that God has created eternal, unchanging laws and not even God can change, since, as some theologians claim, those laws are part of God's nature. These theologians would argue that the moral laws remain unchanged and divine grace simply waives the punishment that normally follows from breaking them.
In ethical objectivism moral values and virtues are intrinsic, not dependent on anything outside of them. In ethical objectivism moral law is uncreated and eternal and not subject to any will, divine or human. (One form of ethical objectivism is moral absolutism.) No will can lessen the consequence of acts against the law. There is no grace in ethical objectivism. In order to avoid punishment, one must perfect one's life and follow the law perfectly. The law of karma, continuous birth, death and rebirth until such moral perfection is reached, appears to be the ultimate expression of ethical objectivism. In Hinduism, Buddhism, and Jainism, for most people one lifetime is not enough for such moral perfection.
The "Law of Karma" holds that if people act in evil ways, that evil will eventually return to them. Conversely, if people do good deeds, then they will advance in spiritual progress. This is connected to reincarnation, where those with a "negative balance" in good deeds will come back in a lower position in society or the animal world.
Ethical subjectivism, as we have seen above, is the opposite of ethical objectivism. Subjectivism says that the moral values are dependent on a human or divine will, that they can change from one situation to another. Please note that a large majority of Christians, Jews, and Muslims believe in moral absolutism, which is a form of ethical objectivism. Also note that Buddhists may have a weaker definition of the law of karma. For some Buddhists it may simply mean that actions have consequences.
When it comes to deciding whether Aristotle, Confucius, and the Buddha are ethical objectivists or subjectivists, you should focus on the following questions: (1) For Aristotle and Confucius who or what tells us the right action? (2) What is the role that God plays for Aristotle and Heaven for Confucius? and (3) Does "relative to" me in each of these thinkers undermine ethical objectivism?
Something has intrinsic value is its value is not dependent on anything outside of it.