If you call your dog's tail, a leg.... How many legs does he have?

From Quote Investigator

In September 1862 a newspaper in Wisconsin reported on a meeting that was held between President Abraham Lincoln and a group of religious leaders who wanted him to immediately sign an Emancipation Proclamation. Lincoln was hesitant and argued that the measure would be ineffective because it would not actually free slaves. He used the language of the riddle to figuratively explain his position:

The committee has returned, and on Saturday evening made a report of their interview with the President to a second meeting of “the religious community” assembled for that purpose. What the President said, one of the delegates told the meeting as follows:

On pressing the policy of emancipation upon the President we received this reply “You remember the slave who asked his master, ‘If I should call a sheep’s tail a leg, how many legs would it have?’

‘Five.’ ‘No, only four; for my calling the tail a leg would not make it so.’ “Now, gentlemen, if I say to the slaves, ‘you are free,’ they will be no more free than at present.”

In October 1862 a newspaper in Indiana reported on the meeting about the proclamation. In this version of the event the president also employed the riddle; however, the animal was a pig instead of a calf: 9

Greeley, Andrew, Blair of Michigan, and other Abolitionists, promised the President a million of men, if he would issue his Emancipation Proclamation. In vain did Lincoln protest; in vain did he cite the stories of the Pope, who issued a bull against the comet, and the slave who told his master that his calling a pig’s tail a leg, would not make it so. He was assured that if he would but spread his edict before the people, armed men would spring out of the earth at the stamp of his foot.

Ultimately, the President signed the Emancipation Proclamation at the beginning of 1863.

Abraham Lincoln may have brought attention to the question but variations of it were in circulation as early as 1825.

Seems like an especially important question these days when so many claims and arguments hinge on non-standard definitions of words. When every identity is a social construct and a personal choice.