Moral relativism is the theory that moral standards vary from society to society, and from time to time in history. Under this theory, ethical principles are not universal and are instead social products. This theory argues that there is no objective moral order or absolute truth. Indeed, variability in what is seen as moral is seen throughout history: with the genocide of the Jews by the Nazi Party, the enslavement of the African people by both European and American powers, the persecution (including torture and murder) of Christians during Roman times and in Communist states, as well as the torture, imprisonment, and murder of scientists during the Eighteenth century by the Catholic Church, all justified by the perpetrators in moral terms. For example, Hitler justified his racial policies by saying:
- The greatest achievements in intellectual life can never be produced by those of alien race but only by those who are inspired by the Aryan or German spirit. In view of the narrowness of the space within which German intellectual work and German intellectual workers have to live they had a natural moral claim to precedence and preference. 
Similarly, the case for slavery was often made in moral terms, with Thomas Dew arguing in 1832 that:
- With regard to the assertion, that slavery is against the spirit of Christianity, we are ready to admit the general assertion, but deny most positively that there is any thing in the Old or New Testament, which would go to show that slavery, when once introduced, ought at all events to be abrogated, or that the master commits any offence in holding slaves. The children of Israel themselves were slave holders, and were not condemned for it.…When we turn to the New Testament, we find not one single passage at all calculated to disturb the conscience of an honest slave holder. 
In recent times, according to the Discovery Institute:
- Moral relativism was uncritically adopted by much of the social sciences, and it still under girds much of modern economics, political science, psychology and sociology. 
Moral relativity is a philosophy that states there is no absolute Right or Wrong, and that anyone can freely use his own conscience to decide what is moral. A moral relativist will not say that theft or murder is wrong, because he believes it is up to the murderer or thief to decide whether his behavior is justified. "There is a way that seems right to a man, but in the end it leads to death." (Proverbs 14:12)
Moral relativity and related foolish thinking is what allows liberals to support abortion, gay rights, and drug abuse. Moral relativity erodes principled self-defense and thereby leads to misguided demands for gun control as well as psychiatric problems resulting from a lack of mental self-defense.
While the idea of moral relativity exists independently of (and substantially predates) the scientific theory of relativity, moral relativists seized on the theory of relativity to legitimize their views. Historians such as Paul Johnson wrote about how the theory of relativity caused a sea change, justified or not, in 20th century thought.
Moral relativism as TUMOR
According to Ryan Dobson moral relativism is a philosophy that can be abbreviated with word TUMOR:
- Tolerant: Moral relativism represents a hypocritical culture in which the "tolerance" is emphasized even though not honored evenhandedly. Criticism is not welcome except against opponents who dare to show their own independent opinion.
- Untraditional: The culture of moral relativism naively favors everything labeled as "alternative": alternative music, alternative voices, alternative, medicine, alternative life styles. The rebellion against traditional values is promoted, often in form of provoking obscene "cultural" expressions. The favorite topic of modern profane relativists is, for example, a fictional story on relationship between Jesus Christ and Mary Magdalene such as one by Jose Saramago in his blaspheme work "The Gospel According to Jesus Christ". Another example might be movie "Million Dollar Baby" which is compared with Nazi movie "Ich klage an" (I accuse) banned by Allies after World War II due to its hidden propaganda promoting Nazi program for euthanasia.
- Marginalized: Moral relativism is a culture that portrays delinquents as "victims". The misdeeds of celebrities, athletes, and politicians are quickly forgotten because their sordid behavior is deemed as driven by the unreasonable demands of fame and fortune. For example, supporters of Bill Clinton never wavered after the truth about the Lewinsky affair came out, claiming he was the victim of a right-wing conspiracy.
- Outdoors: Moral relativism is associated with radical environmentalism. Many of the same protagonists who defend a woman's "right" to kill her unborn child would hurl themselves in front of a bulldozer to rescue a nest of spotted owl eggs.
- Reprobate: Reprobrate means marked with immorality; deviating from what is considered right or proper or good. The culture of moral relativism has adopted an "anything goes" morality, a kind of moral whatever-ness. Individuals are misusing their own rights without respecting the rights of others and often even without sensing they violate them. The typical example is a burglar who broke into private house and sue owners because he slip on their floor.
- Ryan Dobson, Jefferson Scott (2007). Be Intolerant in Love: Because Some Things Are Just Stupid. Sisters, OR, USA: Tyndale House Publishers, 121. ISBN 978-1590-521526.
- Vladimír Palko (2012). Levy prichdzajú (Lions are coming) (in Slovak). Prešov, Slovakia: Vydavateľstvo Michala Vaška. ISBN 978-80-7165-870-2.