Autonomy under uncertainty: the structural limits of substituted judgment in clinical practice

The classical model of informed consent presupposes a competent patient capable of making an autonomous decision on the basis of adequate information. In clinical practice, decisional incapacity, prognostic uncertainty, and time pressure frequently undermine these conditions, making surrogate decision-making both unavoidable and ethically fraught. This paper examines a structural vulnerability within the substituted judgment standard that has received comparatively limited attention in the philosophical literature: the possibility that surrogate authority may be exercised by proxies whose motives are shaped by financial or personal self-interest. Through conceptual analysis and a paradigmatic clinical case from interventional radiology, the paper argues that substituted judgment may become structurally unstable when the motivational integrity of the surrogate cannot be presumed, and that the procedure designed to preserve patient autonomy risks in such conditions becoming a mechanism for its simulation. The paper develops three criteria for reconstructing autonomy under uncertainty: critical evaluation of surrogate testimony, a graduated rather than binary understanding of residual decisional capacity, and an advocacy-oriented conception of the physician's role. The broader argument is that autonomy under conditions of incapacity should not be treated as a pre-existing fact to be recovered but as a normative task requiring active institutional reconstruction - one that calls for calibrated safeguards rather than either default trust or default suspicion.