Two parties is a design flaw of first past the post. There can be regional parties, and occasionally re-alignment elections, but the natural outcome of single member first past the post elections is two big-tent parties with roughly 50% of the seats each.

You need proportional representation or multi-member districts to have more than two stable parties.

My dude, Kant refuted that over two centuries ago. There's no need to invoke a deity or require pure empiricism for morality. Absolute moral rules can be discovered through logical deduction.