relativism

n. belief that judgment and knowledge are dependent upon the particular individual and his environment

Compare moral relativism, aesthetic relativism, social constructionism, cultural relativism, and cognitive relativism. Relativism is the idea that some element or aspect of experience or culture is relative to, i.e., dependent on, some other element or aspect. Some relativists claim that humans can understand and evaluate beliefs and behaviors only in terms of their historical or cultural context. The term often refers to truth relativism, which is the doctrine that there are no absolute truths, i.e., that truth is always relative to some particular frame of reference, such as a language or a culture.
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Noun
1. (philosophy) the philosophical doctrine that all criteria of judgment are relative to the individuals and situations involved
(hypernym) philosophical doctrine, philosophical theory
(classification) philosophy

theories that values don't exist except in relationship to the mind of an individual who values them, or a culture that values them.

relativism