Beneficence is commonly defined as action intended to benefit or promote the good of others. Thus, beneficence is an action taken by a medical professional that serves the best interests of a patient. However, because "the good of others" and "best interests" are subjective concepts, there is no gold standard for beneficence in the physician/patient interaction. The plumbline libertarian has no objections to this definition of beneficence.
However, many bioethicists, after defining beneficence appropriately, then proceed to elevate the physician's subjective evaluation of the patient's "best interests" over the patient's subjective evaluation of the patient's "best interests" when the subjective evaluations of the physician and patient differ (paternalism). The plumbline libertarian opposes paternalism.
Proponents of paternalism assert that paternalism is justified when at least one of several conditions are satisfied. I shall evaluate those farcical conditions in a future blog post.