I believe all but severely limited languages are forced to admit quines, see e.g. https://math.stackexchange.com/questions/3982278/the-fixed-point-theorem-predi

I believe all but severely limited languages are forced to admit quines, see e.g. https://math.stackexchange.com/questions/3982278/the-fixed-point-theorem-predicts-the-existence-of-quines https://math.stackexchange.com/questions/3982278/the-fixed-p...