The structure of English: an introduction to the construction of English sentences -- by Charles Carpenter Fries Harcourt, Brace, 1952
古い本の序文で、陳腐な内容: (Page 9) More than two hundred different definitions of the sentence confront the worker who undertakes to deal with the structure of English utterances.
The common school grammars continue to repeat the familiar definition, "A sentence is a group of words expressing a complete thought," although this ancient definition (which antedates Priscian c. 500 a.d.) quite evidently does not furnish a workable set of criteria by which to recognize sentences.
In actual practice we often ignore the definition with its "complete thought" as a criterion.
If, for example, a reader attempts to count the number of sentences that occur on this or any other page of print, he usually does not stop to decide whether each group counted expresses a "complete thought."
In fact he may not read a single word of the material nor even attempt to discover what the discourse is about.
He simply gives attention to the marks of end punctuation and to the capital letters with which, in our conventions of writing, we begin sentences.