In semiotics, the value of a sign depends on its position and relations in the system of signification and upon the particular codes being used.
Value is the sign as it is determined by the other signs in a semiotic system. For linguist Ferdinand de Saussure, for example, the content of a sign in linguistics is ultimately determined and delimited not by its internal content, but by what surrounds it: the synonyms redouter ("to dread"), craindre ("to fear"), and avoir peur ("to be afraid") have their particular values because they exist in opposition to one another. If two of the terms disappeared, then the remaining sign would take on their roles, become vaguer, less articulate, and lose its "extra something" because it would have nothing to distinguish itself from.
For de Saussure, this suggests that thought is a chaotic nebula until linguistic structure dissects it and holds its divisions in equilibriums. This is akin to the philosophy of
Sir William Hamilton, who indirectly influenced Saussure and believed that the mind could only grasp an idea through distinguishing it from something that it is not. He reasoned that the two objects would otherwise collapse together for the mind and become indistinguishable from one another.
Value determines the sign as a whole, not just meaning. Sound is also an indeterminate nebulous. The arbitrary nature of the sign and the flexibility of sound means that an agreed upon contrast is required. For example, "zena" is useful because it stands in contrast to "zenb" within an agreed upon system. Without the distinction, "zena" could be used for absolutely anything, or indeed nothing, making communication an impossibility.
It is only the sign as a whole that has value. Linguistic structure simultaneously unites sound with thought and decomposes "thought-sound" into linguistic units, or signs, consisting of a signifier and a signified (sound-pattern and concept, respectively). When analysed in isolation, the sound-pattern or concept are pure differences, emerging from series of sound-patterns or concepts that they themselves are dependent upon.