Final answer:
The principle that establishes the patient as the ultimate decision maker in clinical settings is the principle of autonomy, which emphasizes patients' right to self-determination and informed consent.
Step-by-step explanation:
The conviction that states that the patient must be the ultimate decision maker is built upon the principle of autonomy. The principle of autonomy asserts that patients in clinical settings have the right to exercise agency or self-determination in their health care decisions. This is fundamental in the practice of informed consent, where an individual is provided with all the relevant information to make their own decision regarding their health care options, thus safeguarding patient autonomy and preventing exploitation.