Disingenuity and intellectual dishonesty

Yes and no.

The two expressions are clearly kindred spirits. But there is. subtle difference that is hard to pin down. It is a matter of tone as much as semantic extension.

Start with the root word: ingenuous (which the spell-check is convinced should be ingenious!). Merriam Webster defines it thus:

showing innocent or childlike simplicity or candidness <sic, rather than candour.

The French speak of an ingenu: an innocent or simpleton. So its opposite, disingenuous is the negation or absence of that quality. More than that, though, it is a false simulation of innocence, ignorance or naiveté.

In that sense, it is a cousin of something attributed to Socrates: ‘ειρωνεία’, often translated into the cognate English, irony, in the context of his repeated claim to be ignorant or baffled, while demolishing the opinions of his interlocutors. Whether Socrates was being presented to us by Plato or Xenophon as disingenuous, is uncertain, but in Plato, at least, Socrates’ victims are calling him disingenuous. What is certain is that he was not being accused of intellectual dishonesty.

In U.K. political campaigns of the 1980s and ‘90s, A habit by the government party grew up, in which the spokesperson would respond to challenges that if the party won it would raise these taxes or cut those social benefits, in the following disingenuous way:

We have no plans to do that.

Whatever the party does later, even if it does raise the taxes or cut the taxes, they can still insist that they were not lying.

We had no plans at the time, but now we can see it is necessary.

Nobody can prove them false, but most people can see perfectly well that the government is being disingenuous. The statement was true. There was nothing on paper showing the detailed steps and amounts: nothing you could call a plan.

But this kind of behaviour is not intellectually dishonest. Indeed there is nothing intellectual about it. There is a reasonable stab at an explanation of this expression.

Harvard ethicist Louis M. Guenin describes the "kernel" of intellectual honesty to be "a virtuous disposition to eschew deception when given an incentive for deception". Intentionally committed fallacies in debates and reasoning are called intellectual dishonesty.

So both are a kind of dishonesty, where disingenuousness is not exactly designed to deceive. It is rather a withholding of ‘the whole truth’. One British diplomat used the expression ”economical with the truth”, leaving everyone to understand that the minister concerned had uttered a deception without actually saying so. And in so expressing himself, the diplomat was being disingenuous (and very diplomatic!).

So no, the two are not the same.

BUT... If you study the examples cited in the Cambridge English Dictionary, actual usage has tended to blur the difference between the two expressions. So, regretfully, I have to say that yes, the difference is fading. It is not wrong to use disingenuous where intellectually dishonest or just dishonest (I should have said) would be better. It is a pity. Disingenuousness is not actually trying to deceive.