Objection might be made […] that the potentialities of substitution cannot be used to distinguish portions of speech; for these should be distinguished by their internal structure, independently of what substitutions occur in partially different utterances. However, experimental work in the psychology of perception, especially that due to Gestalt psychologists, leaves little doubt that an utterance is perceived not as an independent structure but in its relation to other utterances. Therefore any differences in substitution potential which can be recognized from the structure of an utterance are relevant even to that utterance alone (and are certainly relevant to the whole language).
- Harris (1951), a pag.273, n.27