You Know what the Autistic Are Like

In his novel, "the curious incident of the dog in the night-time," Mark Haddon puts a joke much like this into the words of his protagonist, a young boy we might call autistic.

~ An economist, a logician, and a mathematician were on a train to Scotland. Looking out the window as they enter Scotland they see a brown cow standing parallel to the train.
The economist says, "Look the cows in Soctland are brown."
The logician says, "No,, there are cows in Scotland of which ast least one is brown."
The mathematician says, "No, there is at least one cow in Scotland, of which one side appears brown." ~

Haddon has his hero explain the joke like this " ...it is funny because economists are not real scientists, and because logicians think more clearly, but mathematicians are best."

Maybe one needs to read the book.