Whitehead's account of the functions of what he terms «symbols in Symbolism and Process and Reality offers a suggestive attempt at
such an extension.4 In the first of these works two basic forms of symbols are distinguished:
linguistic expressions in the form of perceived words and sentences and our sense presentations correlated to natural objects.
This type of argument is again broadly evidentiary in nature, although it reflects not the «turn to the subject» characteristic of the appeal to individual experience, but rather a «pragmatic» or «
linguistic» turn, as illustrated by Whitehead's observation that the evidence of human experience as shared by civilized intercommunication «is also diffused throughout the meanings of words and
linguistic expressions» (cited in TPT 74).12
Such an appeal is an essentially historical form of argumentation.