I am hoping to defend naturalistic moral realism using a similar abductive argument we employ for scientific realism. In doing so, I need to say that successful normative theories are instrumentally reliable.
A theory is instrumentally reliable iff the theory provides accurate observational predictions.
I suppose for many people it is not familiar to think whether normative theories achieve theoretical successes in a way empirical scientific theories would do. Below, I propose one simple way to think the instrumental reliability of my sample consequentialism.
My sample consequentialism says that any act or rule is good iff that act or rule contributes the realisation of important human needs. These human needs include such needs: physical, mental, intellectual, human relationships (family, love, friendship), etc.
Given this sample consequentialism, let’s think whether we can have any such ‘instrumentally reliable consequentialist theory’.
The consequentialist starts out with some simple consequentialist principles. For instance, the consequentialist might hold a moral theory that maintaining fairness in a society contributes to the homeostasis of human flourishing in that society. We can examine whether this moral theory is ‘instrumentally reliable’. At this point, the consequentialist has a rough definition of fairness: fairness is realised iff everyone is treated equally. Given this definition of fairness, now, the consequentialist provides an observational prediction:
(P) If everyone in a country is treated equally, the realisation human flourishing is better achieved than the realisation of human flourishing in a country where people are not treated equally.
I propose the following assumptions as reasonable to be accepted.
A1. (P) is empirically confirmable. If we can see an obvious difference between the realisation of human flourishing in countries where people are treated equally and the realisation of human flourishing in countries where people are treated not equally, we can confirm (P) as an approximately true prediction.
A2. If a theory is capable of providing observational predictions, and such predictions are empirically confirmable, once the prediction is really confirmed, that theory is regarded as instrumentally reliable.
A3. Whether (P) is in fact confirmed against empirical observation is a contingent matter.
Having these assumptions as reasonable assumptions, I conclude that consequentialist theories could be, in principle, instrumentally reliable. Furthermore, I would like to argue we would see an obvious difference between the world where everyone is treated equally and the world where everyone is treated unequally.
If what I have said above are somehow defensible, it will be good news for the defender of the abductive argument for moral realism. I wonder what people would say about such a proposal.