Conversation so far:
What was Immanuel Kant's stance on major political ideals?
Immanuel Kant believed that universal history leads to the ultimate world of republican states at peace, but his theory was not pragmatic.
Are there any other interesting aspects about this article, besides Immanuel Kant's stance on major political ideals?
Immanuel Kant invented critical philosophy, that is of the notion of being able to discover and systematically explore possible inherent limits to our ability to know through philosophical reasoning

Question: Were there any problems with his theory?
Self-contained rewrite: Were there any problems with Immanuel Kant's theory?