One of my current areas of research is the relationship between the concepts of weight and evidence. I’m interested in weight of evidence issues because various philosophical concepts (reasons, intuitions, judgments, and so on) are used as evidence for certain philosophical claims. The weight attached to these philosophical concepts, either implicitly or explicitly, determines the conclusions reached through their use. So, you could imagine my delight when I came across a blog post that featured the concept of a weighty moral reason in arguing for a specific conclusion.
In the blog post I’m referring to Mike Almeida proposed a two-part argument. Using premises from an argument about saving non-persons a second argument derived the conclusion that non-persons can be terminated. Within the second argument the concept of a weighty moral reason is doing a lot of the heavy lifting. When I pressed Mike about the concept he softened the strength of the concept by trying to claim something non-controversial. As a response, I stipulated a plausible meaning for the concept of a weighty moral reason, and I tried to show that his non-controversial rendering (i.e. a very good reason) is less effective than my rendering when it comes to the kinds of moral situations his argument attempts to handle. The post I’m referring to is found here. For your consideration, my stipulated version of a weighty moral reason runs as follows:
(WMR) The weight W of a morally relevant reason R is directly proportional to the probative force F it exerts on a moral claim M; a particular reason R qualifies as weighty if it exerts enough probative force F on moral claim M to cause M to cross the threshold of genuine belief (i.e. assert M as true).