AbstractDefault positions, predetermined starting points that aid in complex decision-making, are common in clinical medicine. In this article, we identify and critically examine common default positions in clinical ethics practice. Whether default positions ought to be held is an important normative question, but here we are primarily interested in the descriptive, rather than normative, properties of default positions. We argue that default positions in clinical ethics function to protect and promote important values in medicine-respect for persons, utility, and justice. Further, default positions in clinical ethics may also guard against harm. Where default positions exist, there are epistemic burdens to overturn them. The person wishing to reject the default position, rather than the person endorsing it, bears this burden. The person who bears the burden of meeting the epistemic requirements must provide evidence proportional to the degree of harm the default position protects against. Default positions that protect against significant harm impose significant epistemic requirements to overturn. This asymmetry not only makes medical decision-making more economical but also serves to promote and protect certain values. The identification and analysis of common and recognizable default positions can help to identify other default positions and the conditions under which their associated epistemic requirements are met. The article concludes with considerations of potential problems with the use of default positions in clinical ethics.