Would appreciate either theoretical explanations or illustration using examples. I am new to the forum, and it appears to me that both rationalists and utilitarianists would use "utility maximization" as the key decision criterion. Maybe for rationalists, "utility" is defined narrower because certain values are upheld or preferred over others (e.g. uphold Truth and the scientific process).
Take an example from daily life, say your friend bought you a jacket as a gift. You find the jacket hideous. Your friend asks you how you like the jacket. Should you tell the truth (e.g., doesn't think it suits you) or should you tell a white lie (e.g., you love it)? Would the decision-making calculus of a rationalist differ from that of a utilitarianist?