What does Sargent mean by possible, probable and plausible, and why does he say a true but improbable incident should be cut?

Sargent (ch. XII 'Plausibility') says an incident can be explained, prepared for and correctly coloured and still fail because the average spectator will not accept it as a likely thing. His test is acceptance, not truth: 'possible' is not 'probable', and a possible but improbable incident is worse than a fantastic one that is offered as imagination. So he tells writers to prefer a story that sounds true to one that is true, and to drop true events that are too strange. The exemption is a declared fantasy. His examples (Capitol dome, policeman and aeroplane, sea serpent, Verne) illustrate these claims; none is tested. The standard is an editor's account of the 'average spectator' in 1916. Curator qualifications: Plausibility-as-acceptance verified; cross-chapter pointers (XXII, LIV) confirmed in the correct chapters. Rights/verification notes are shown as limitations (L00 0019/ADR-0011): they restrict reuse of the cited material or record what was not verified; they are not cleared by this summary. Limitations: [component_reuse_restriction] Internet Archive OCR text; licence of the scan not re-read here (public-domain 1916 text per prior S10 review). Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://archive.org/stream/techniqueofphoto00sarg/techniqueofphoto00sarg_djvu.txt",
      "note": "sar.flat chars 111315-118828 (ch. XII)"
    }
  ]
}