Tacitly opting out of organ donation: too presumptuous after all?

In his latest defence of opt-out organ donation, Ben Saunders argues that opt-out does not depend on presuming consent but instead entails a donor tacitly consenting to making her organs available for transplantation.1 Consent is implied, not merely presumed, in the absence of a registered objection because consent is always an act—a purposeful action or inaction—not a mental attitude of approval. Saunders' argument hinges on a strong interpretation of consent as a performative utterance in which the act is sufficient and the mental attitude is unnecessary. Once social conventions have established which (in)action constitutes consent, Saunders argues, a person who has performed the relevant act—whether expressly or tacitly—incurs the obligations pursuant to giving her consent. The fact that she may have performed this act without intending to consent is immaterial. This last point seems to take us a step too far. Instead of insisting that an act constitutes consent regardless of a person's intention to approve, it seems more reasonable to adopt the view that, under normal circumstances, acts of consent ought to be minimally approval-tracking. We might think a consent procedure to be ‘minimally approval-tracking’ when the probability of the consenting act coinciding with what the ‘consenter’ really wants (independently of the procedure) satisfies some threshold value—for example, more than 50%. Or, in comparative terms, we might evaluate two different consent procedures according to how well they appear to track what ‘consenters’ really want. Take the familiar example of the …