A plausible assumption is that the principles of language are fixed and innate. (Chomsky 2000: 122; New Horizons)
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A plausible
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the
  principles of language are fixed and innate | ||||||
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 | 
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A plausible assumption | 
is | 
the principles of language  | 
are | 
fixed and innate | 
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Rheme | |||
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New | |||
Of course, this is not a plausible assumption, because Chomsky also assumes that the principles of language are components of a "genetically-determined" language faculty, and as the evolution of biological species demonstrates, genes and their expressions are not "fixed".  If they are "innate", they are not "fixed".  Platonic essentialism/idealism is not empirical science.
 
