The problem was whether they were right?
Or whether, to apply Mr.Pierce's formula, they merely imposed their own frame of mind in place of Stirling's, and decided, since their sole reason for walking at the moment would be entirely hygienic, that he too must be striding from the same cause?
Dr.Holmes tells us that when James and Thomas converse there are really six talkers.

First, James as James thinks he is, and Thomas as Thomas thinks he is.

Second James as Thomas thinks him, and Thomas as James thinks him.

Finally, there are James and Thomas as they really are.
Since this is neither an autobiography nor an inspired story, the world's view of Peter Stirling must be adopted without regard to its accuracy.

And because this view was the sum of his past and personal, these elements must be computed before we can know on what the world based its conclusions concerning him.
His story was as ordinary and prosaic as Mr.and Mrs.Pierce seemed to think his character.