What does he mean by 'others'?
Who is Capella bringing with him ?" "Witnesses," volunteered Winter.
"Just so; but witnesses in what cause ?" "How the--how can I tell ?" "By applying your borrowed logic.

Try the deductive reasoning you flung at me a while ago." "I don't quite know what 'deductive' means," was the sulky admission.
"That is the first step towards wisdom.

You admit ignorance.

Deduction, in this sense, is the process of deriving consequences from admitted facts.
Now, mark you.

Capella wishes to be rid of his wife, by death or legal separation.