9.4 Complex (Leading) Questions
From 9. Common Fallacies in Clear Thinking by R W Jepson

These are interrogative forms of question-begging. Perhaps the most familiar example is:

Have you ceased beating your wife?

The person asked this question cannot reply by a plain Yes or No, without also assenting to the assumption, contained in the question, that he had, at some time, been in the habit of beating his wife. The question, of course, can be answered by dealing with the assumption first, i.e.,

"I have never been in the habit of beating my wife, and therefore the question whether I have ceased to do so does not arise."

But it takes time and deliberation. A nervous witness during cross-examination could be made to make very damaging admissions by unscrupulous use of this type of question on the part of counsel.

Charles II once proposed to the Royal Society as a question,

"Why is it that a vessel of water receives no addition of weight from a live fish being put into it, though it does if the fish be dead? "

It was not surprising they were unable to give a satisfactory reply, because the fact assumed in the question was not a fact at all!