Having read the article , it seems to me that the point being made is not it is impossible to write a Python 2 interpreter in Python 3 , but rather the developers don ' t want Python 2 to be implementable in Python 3 , and the current politics around Python 3 are a reflection thereof . I ' m no Python programmer , so I can ' t really attest to whether he has a real point there I ' m not convinced there ' s surely a way to write a Python 3 interpreter in Python 2 , but if his observations are true , then the 23 rollout is the philosophical opposite of the transition of Perl 5 to Perl 6 , where being able to interpret Perl 5 from within a Perl 6 environment seems to be much more . endorsed ? There ' s supposedly a Perl 5 implementation for the Parrot VM , for example , which means that Perl 5 and Perl 6 can hypothetically coexist for an easier transition if one is even necessary .