Population Thinking Vs Platonic Essentialism In Linguistic Theories

Edelman (1992: 73):

It is not commonly understood that there are characteristically biological modes of thought that are not present or even required in other sciences. One of the most fundamental of these is population thinking, developed largely by Darwin. Population thinking considers variation not to be an error but, as the great evolutionist Ernst Mayr put it, to be real. Individual variance in a population is the source of diversity on which natural selection acts to produce different kinds of organisms. This contrasts starkly with Platonic essentialism, which requires a typology created from the top down; instead, population thinking states that evolution produces classes of living forms from the bottom up by gradual selective processes over eons of time.

Blogger Comments:

Linguistic theories can be distinguished according to whether they embrace population thinking or Platonic essentialism.  

Population thinking, where variation is treated as real, underlies the dimension of instantiation in Systemic Functional Linguistics.  The frequencies of features in instances of language, texts, establish the probabilities (of instantiation) of such features in the overall system of potential.  Registers of language vary in terms of instantiation probabilities of system features, or, from the complementary perspective, text types vary in terms of the frequencies of feature instantiations.  Language change occurs when the frequency of a new variant in texts significantly raises its systemic probability of being instantiated.

Platonic essentialism, where variation is treated as error, underlies the distinction between competence and performance in Chomskyan Formal Linguistics.  As Chomsky (1965) declared:

Linguistic theory is concerned primarily with an ideal speaker-listener, in a completely homogeneous speech-community, who knows its (the speech community's) language perfectly and is unaffected by such grammatically irrelevant conditions as memory limitations, distractions, shifts of attention and interest, and errors (random or characteristic) in applying his knowledge of this language in actual performance.

Population thinking accommodates evolutionary and developmental change; Platonic essentialism does not.