Markus Herrmann

The objective of explainable artificial intelligence systems designed for clinical decision support (XAI-CDSS) is to enhance physicians’ diagnostic performance, confidence and trust through the implementation of interpretable methods, thus providing for a superior epistemic positioning, a robust foundation for critical reflection and trustworthiness in times of heightened technological dependence. However, recent studies have revealed shortcomings in achieving these goals, questioning the widespread endorsement of XAI by medical professionals, ethicists and policy-makers alike. Based on a surgical use case, this article challenges generalising calls for XAI-CDSS and emphasises the significance of time-sensitive clinical environments which frequently preclude adequate consideration of system explanations. Therefore, XAI-CDSS may not be able to meet expectations of augmenting clinical decision-making in specific circumstances where time is of the essence. This article, by employing a principled ethical balancing methodology, highlights several fallacies associated with XAI deployment in time-sensitive clinical situations and recommends XAI endorsement only where scientific evidence or stakeholder assessments do not contradict such deployment in specific target settings.

With regard to current debates on the ethical implementation of AI, especially two demands are linked: the call for explainability and for ultimate human responsibility. In the medical field, both are condensed into the role of one person: It is the physician to whom AI output should be explainable and who should thus bear ultimate responsibility for diagnostic or treatment decisions that are based on such AI output. In this article, we argue that a black box AI indeed creates a rationally irresolvable epistemic situation for the physician involved. Specifically, strange errors that are occasionally made by AI sometimes detach its output from human reasoning. Within this article it is further argued that such an epistemic situation is problematic in the context of ultimate human responsibility. Since said strange errors limit the promises of explainability and the concept of explainability frequently appears irrelevant or insignificant when applied to a diverse set of medical applications, we deem it worthwhile to reconsider the call for ultimate human responsibility.

In multiple parts of the Critique of Pure Reason, Kant describes how time is dependent on space – which is the fundament of his distinction between inner and outer sense. However, he does not provide us with an argument for this dependency. In this article, two reasons for this dependency thesis are introduced. The first one aims at providing a conceptual link between time and space but runs into conflict with the Transcendental Aesthetic. The second one shifts our focus from the conceptual level to a priori possible objects of experience: Time cannot provide such objects, which are different from our subjective states due to its one-dimensionality. Only space makes such objects possible.