Use "fixed idea" in a sentence

1. An Amputee wannabe has a very fixed idea of which limb is unwanted, and what level of amputation will make them a “whole” person

2. Walker says, “To be regardful of others within reason, is intelligent egoism in the first place,” but it must not become a fixed idea, expressing or leading to self-sacri fice, worship, mental slavery, superstition, or any other form of Antiegoist thought