Choosing Less Harmful Alternatives: The Ethics of Harm Reduction in Emerging Technologies.

When are we obligated to choose less harmful alternatives to existing practices? This article addresses this deceptively simple question by developing the Principle of Choosing Less Harmful Alternatives (PCLHA), which holds that it is morally wrong to continue to engage in a practice that causes harm when an affordable, accessible, functionally equivalent, less harmful alternative exists. While PCLHA pertains to any practice for which its conditions are met, the principle is particularly valuable for contingent (rather than intrinsic) wrongs, delineating a sufficient condition for when technological or social progress renders once-permissible practices impermissible. I pressure-test PCLHA by applying it to emerging technologies across several domains, including food ethics (cultivated meat), transportation ethics (autonomous vehicles), and leisure ethics (virtual reality tourism and sex bots). Through these applications, I demonstrate that the principle faces two opposing challenges: it appears simultaneously too weak, by not requiring switches to less harmful alternatives when they fall short of full functional equivalence (e.g., allowing factory farming despite massive harm), and too strong by requiring switches to alternatives in cases where this feels intuitively overreaching (e.g., mandating virtual reality tourism). I address these challenges via complementary modifications to PCLHA: a ‘Sliding Scale Modification’ that allows the required degree of functional equivalence to vary with harm severity, and a ‘Threshold of Harm Qualification’ that limits PCLHA’s application to cases of significant harm.