What is Ignoratio Elenchi?

Ignoratio elenchi is one of the oldest fallacies known to us, being first identified by Aristotle. When someone believes himself to be proving one thing, but succeeds in proving something else instead, he commits ignoratio elenchi. He not only argues beside the point, but directly to a different conclusion.


I shall oppose this measure to permit people to leave school earlier by proving once again the value of education.

(Proving the value of education does not prove the case against permitting earlier leaving. Perhaps it takes education, as opposed to schooling, to see the difference.)


The thesis which is proved is not relevant to the one which the arguer sought to prove, which is why this is sometimes known as the fallacy of irrelevant thesis. The fallacy consists of supposing that the one conclusion equates with the other, when in fact they make separate points. The arguments which would support the first conclusion are omitted, and those which support the irre-levant conclusion are brought in instead.


How could my client have ordered the murder? I have proved beyond a shadow of doubt that he was not even in the country at the time.

(Well done. Does that show he didn’t order it before he left, or arrange it by telephone?)


Ignoratio elenchi has a subtle appeal. Its strength lies in the fact that a conclusion is validly proved, even though it is the wrong one. Anyone who concentrates on the argument may well find that its soundness diverts his attention away from the irrelevant conclusion.


Is gambling a worthwhile occupation? Believe me, we not only work as hard as anyone else, but harder. It takes hours of study every day, quite apart from the time spent doing it.

(OK, it’s hard work. Now, is it worthwhile?)


Ignoratio elenchi makes its brief, but usually successful, appearance, wherever someone accused of doing something he did do, is quite prepared to deny something else. It is a central feature of all points where journalistic and political circles touch. The use of the fallacy has an almost ritual quality to it. Whether it is under the steady beam of studio lights, or the staccato illumination of flash cameras in the streets, the little tableau is enacted. The eager pressmen solemnly charge the great man with one thing, and he, with equal solemnity, shows that he has not done another.


‘Isn’t it true, Minister, that you have allowed the living standards of the poor to fall in real terms?’

‘What we have done is to increase by 3.7 percent the allowance childless dependent females, and by 3.9 percent the allowance to widows with two children, these increases both being larger than opponents ever managed in a single year of their term of office. ‘


In the more relaxed atmosphere of a studio interview, the great man will often brazen it out, with royal trumpeters announcing his ignoratio elenchi:


Well, John, that’s not really the point, is it? What we have done is to…

(And you can bet that this certainly isn’t the point.)


Obviously you can use the fallacy for close-quarters defensive work. Your audience will be so impressed by all the things which you can prove you have not done, that their attention might wander away from those you have. The more laborious and detailed your proofs, the less chance there is of anyone remembering what it was you were actually accused of.

You can also use it in an attacking role, proving all kinds of things except the ones that matter. There are many things which can be demonstrated about nuclear power, hunting animals and refined white sugar which are not relevant to the central topic of whether others should be banned from doing things you do not approve of.


Jogging in public should be banned. There are studies which show increase the risks to health, rather than decrease them.

(Even if it were true, would it be an argument for banning public jogging? It sounds as though the major adverse effect is not on the jogger’s health, but the speaker’s conscience.)