twins-3
Explanation
The Joke
A woman excitedly meets another woman's twins and asks if they have been given "cute" names, "butterfly" names, or names from books. The mother -- revealed to be a mathematician -- responds with increasing exasperation: "Lady, I'm a mathematician. I only use real, rigorous terms. None of this frivolous nonsense for my kids." When finally asked what the twins' names are, she reveals they are "Bertrand" and "Brillouin," both named after famous mathematicians and physicists.
The Humor
The comic plays on the stereotype of academics (particularly mathematicians and scientists) who claim to be above frivolous naming conventions but end up being just as quirky in their own way. The mother insists she is being rigorous and practical, but naming your twins after Bertrand Russell and Leon Brillouin is arguably more esoteric and pretentious than any "butterfly" name could ever be. The humor lies in the gap between the mathematician's self-image as a no-nonsense pragmatist and the reality that she is deeply sentimental about her field -- she has just swapped one form of whimsy for another.
References
Bertrand likely refers to Bertrand Russell (1872-1970), the British mathematician, logician, and philosopher known for foundational work in mathematical logic. Brillouin likely refers to Leon Brillouin (1889-1969), the French-American physicist known for contributions to quantum mechanics and information theory, including Brillouin zones in solid-state physics.