How to Win Every Argument: The Use and Abuse of Logic (2006)

The complex question (plurium interrogationum) 29

government in the 1960s, adopted after the most serious public

debate, was based upon a relatively obvious circulus in probando.

This was the National Plan, an exercise in (then fashionable)

national economic planning. Firms were asked to assume a

national growth-rate of 3.8 per cent, and to estimate on that

basis what their own plans for expansion would be. These various

estimates were added up by the government, which concluded

that the combined plans of British industry suggested a growth-

rate of 3.8 per cent!

The National Plan was valueless then and subsequently,

except to connoisseurs of logical absurdity lucky enough to snap

up remaindered copies of it in secondhand bookshops.

The complex question (plurium interrogationum)

Plurium interrogationum, which translates as 'of many questions',
is otherwise known as the fallacy of the complex question. When
several questions are combined into one, in such a way that a
yes-or-no answer is required, the person they are asked of has no
chance to give separate replies to each, and the fallacy of the
complex question is committed.

Have you stopped beating your wife?

(If 'yes', you admit you were. If 'no', then you still are.)

This might seem like an old joke, but there are modern

versions:

Did the pollution you caused increase or decrease your profits?

Did your misleading claims result in you getting promoted?

Is your stupidity inborn?