相对主义是怎么解释的？哪位哲学家给解释解释。。。

相对主义的前后矛盾 近些年来，不同的历史学家、社会学家和科学哲学家都信奉了相对主义，他们之所以被相对主义吸引，在一定程度上是由于它具有明显的解释力。相对主义者使人有这样的印象，即信念和推理会因时代和社会群体的不同而具有多样化。较为极端的相对主义者告诉历史相对主义意指一种以怀疑历史知识的客观性为特征的史学流派，它认为历史不是实际发生的往事，而是史学家基于现实需要并蕴涵自身价值观的主观建构的话语。他们试图引入价值判断、分析词与物的关系、诠释时间的可塑性与探讨历史解释的多样性等，力求阐明职业史学家无法产生客观的历史知识、历史学亦无缘成为一门科学，藉此颠覆历史叙述的符合论与解构历史的真实性。20世纪西方史学实践表明，历史相对主义存在多重类型及表现。然而，此流派本身却是个多面向的矛盾体，它无法证明“自我指涉”的合法性。换句话说，“元叙述”的缺失不仅驳斥了历史的“宏大叙事”，而且宣称了建构历史知识的虚无主义。当然，历史相对主义丰富了历史编纂理论的意蕴，凸显了史学研究的主体性。同时，史学研究从认识历史真相扩展到审美情趣、道德伦理与政治正确等功能，实现了跨学科的方法论取向。就此而论，历史相对主义开阔了史学家研究的视野，有助于建立一种开放的、多元的与容

【】要权威的话，是不能相信中国人写的哲学辞典的。我从“《剑桥哲学辞典》 英文第二版”找出了关于相对主义比较全面和权威的解释，不过就是英文版的。


relativism（相对主义）, the denial that there are certain kinds of universal truths. There are two main types,cognitive and ethical. Cognitive relativism holds that there are no universal truths about the world: the world has no intrinsic characteristics,there are just different ways of interpreting it.
The Greek Sophist Protagoras, the first person on record to hold such a view, said, “Man is the measure of all things; of things that are that they are,and of things that are not that they are not.”
Goodman, Putnam, and Rorty are contemporary philosophers who have held versions of relativism.Rorty says, e.g., that “ ‘objective truth’ is no more and no less than the best idea we currently have about how to explain what is going on.” Critics of cognitive relativism contend that it is self-referentially incoherent, since it presents its statements as universally true, rather than simply relatively so. Ethical relativism is the theory that there are no universally valid moral principles: all moral principles are valid relative to culture or individual choice. There are two subtypes: conventionalism, which holds that moral principles are valid relative to the conventions of a given culture or society; and subjectivism, which maintains that individual choices are what determine
the validity of a moral principle. Its motto is, Morality lies in the eyes of the beholder. As Ernest Hemingway wrote, “So far, about morals,I know only that what is moral is what you feel good after and what is immoral is what you feel bad after.”
Conventionalist ethical relativism consists of two theses: a diversity thesis, which specifies that what is considered morally right and wrong varies from society to society, so that there are no moral principles accepted by all societies; and a dependency thesis, which specifies that all moral principles derive their validity from cultural acceptance.From these two ideas relativists conclude that there are no universally valid moral principles applying everywhere and at all times.The first thesis, the diversity thesis, or what maysimply be called cultural relativism, is anthropological;
it registers the fact that moral rules differ from society to society. Although both ethical relativists and non-relativists typically accept cultural relativism, it is often confused with the normative thesis of ethical relativism.The opposite of ethical relativism is ethical objectivism,which asserts that although cultures may differ in their moral principles, some moral principles have universal validity.Even if, e.g., a culture does not recognize a duty to refrain from gratuitous harm, that principle is valid and the culture should adhere to it. There are two types of ethical objectivism, strong and weak. Strong objectivism, sometimes called absolutism, holds that there is one true moral system with specific moral rules. The ethics of ancient Israel in the Old Testament with its hundreds of laws exemplifies absolutism. Weak objectivism holds that there is a core morality, a determinate set of principles that are universally valid (usually including prohibitions against killing the innocent, stealing, breaking of promises, and lying). But weak objectivism accepts an indeterminate area where relativism is legitimate, e.g., rules regarding sexual mores and regulations of property. Both types of objectivism recognize what might be called application relativism,the endeavor to apply moral rules where there is a conflict between rules or where rules can be applied in different ways. For example, the ancient Callactians ate their deceased parents but eschewed the impersonal practice of burying them as disrespectful, whereas contemporary society has the opposite attitudes about the care of dead relatives; but both practices exemplify the same principle of the respect for the dead.According to objectivism, cultures or forms of life can fail to exemplify an adequate moral community in at least three ways: (1) the people are insufficiently intelligent to put constitutive principles in order; (2) they are under considerable stress so that it becomes too burdensome to live by moral principles; and (3) a combination of (1) and (2).
Ethical relativism is sometimes confused with ethical skepticism, the view that we cannot know whether there are any valid moral principles.Ethical nihilism holds that there are no valid moral principles. J. L. Mackie’s error theory is a version of this view. Mackie held that while we all believe some moral principles to be true, there are compelling arguments to the contrary.Ethical
objectivism must be distinguished from moral realism, the view that valid moral principles are true, independently of human choice. Objectivism may be a form of ethical constructivism, typified
by Rawls, whereby objective principles are simply those that impartial human beings would choose behind the veil of ignorance. That is, the principles are not truly independent of hypothetical
human choices, but are constructs from those choices.
See also ETHICAL OBJECTIVISM, ETHICS,
MORAL EPISTEMOLOGY, MORAL REALISM,
SKEPTICISM. L.P.P.参考资料：《剑桥哲学辞典》 英文第二版