Can science discover moral facts?
Carrier is following Sam Harris' lead by putting this provocative claim in the title, and — like Harris — doing some philosophy first to analytically reduce moral facts to scientifically-accessible components. So the really controversial steps are philosophical rather than scientific.
I'm familiar with moral philosophy. Give me the short version!
Moral facts are whichever hypothetical imperatives correspond to an individual's deepest desires. Human-universal moral facts exist because all humans share a set of deepest desires. Since science can investigate both hypothetical imperatives and desires, science can discover human-universal moral facts.
What makes 'ought' claims true?
Let's start by looking at conditional 'ought' claims (aka hypothetical imperatives).
If you want to wake up in time for work, you ought to set an alarm clock.So if I really do want to become a doctor and there really is this connection between studying diligently and becoming a doctor, then I really ought to study diligently. Carrier points out that both of these prerequisites are open to scientific investigation. "And wherever both are an empirically demonstrated fact, the imperative they entail is an empirically demonstrated fact."1 This means that science can discover 'ought' facts, not just 'is' facts.
If you want your car to stay put, you ought not park in a tow-away zone.
If you want to become a doctor, you ought to study diligently.
What makes an 'ought' claim a moral 'ought' claim?
The majority view has been that moral 'oughts' are different from the above kind of 'oughts' because they're not conditional on what a person wants. Carrier disagrees on the grounds that any system of imperatives which doesn't line up with what a person most wants can't count as morality, because that person will "have a better reason to do something else instead."2
Instead of viewing morality as something that stands in opposition to our desires, morality has to do with what fulfills our deepest desires. It's just that, sometimes, we're mistaken about what promotes our own deepest desires. "What we really want most, and what will really obtain that, are matters of fact that cannot truly be answered from the armchair. Empirical methods must be deployed to ascertain and verify them. Only science has the best tools to do this."3
Doesn't this make morality an individual thing?
Even if morality is grounded on the individual level, there may still be universal moral facts if some moral facts apply to every individual. (Or at least human-universal moral facts if all humans share some moral facts.) Carrier argues that it's likely all humans have the same set of deepest desires.
"Only if what an individual wants most (when rational and sufficiently informed) is not the same as for everyone else will this not be the case. Then, a different set of moral facts will be true for them (yet even then true moral facts still exist, they are just again relative to different groups or individuals.) But that outcome is very improbable for members of the same species."4Carrier's justification for this statement is hard to follow, but it goes something like this:
Humans share many biological facts, and these facts generate a hierarchy of high-order desires that we're stuck with, i.e. we can't just change them without altering our natural humanity. "For example: we all need to eat, breathe, move, think, and cooperate and socialize with a community[....]"5 The way these fundamental desires play out for individuals may differ, but we share our most basic biological needs.
Biological differences among humans aren't sufficient to change these high-order desires, at least not without extreme genetic mutation.
Environmental differences only make a difference in how our fundamental human desires play out. Same algorithm; different results. If I had lived life in your shoes, I would want most the things you want most.
So, ultimately, only our shared human biology determines our high-order/foundational/deepest desires, which in turn determine what is morally right for all of us in general terms, and what is right for each of us when applied to our individual situations. To use one of Carrier's examples, we all have fundamental desires to eat and to avoid pointless harm, which might make it morally right for me to eat strawberries but morally right for you to avoid eating strawberries because you're allergic to them; we're both following the same basic imperatives of eating and avoiding pointless harm, which means there is no real difference in moral facts here.
To review, Carrier believes moral facts are open to scientific inquiry because his metaethics reduce moral facts to facts about the effectiveness of means to ends (hypothetical imperatives) and psychology (what a person most fundamentally desires). This would be enough to explain how moral facts "naturally exist" and how "science could find them," but he goes one step farther and argues that humanity shares one set of moral facts.
Carrier's chapter is followed by an appendix containing, as he puts it: "formal deductive proofs of every one of these conclusions, fully verifying that they are necessarily true."6 I appreciate his boldness! Still, I disagree with his moral philosophy at several points, as I will explain in the next post [which is here, but only covers one point of disagreement].
1. Carrier, R. (2011). Moral facts naturally exist (and science could find them). In Loftus, J.W. (Ed.), The end of christianity (pp. 333-358). Amherst, New York: Prometheus Books. p. 335
2. ibid. p. 343
3. ibid. p. 342
4. ibid. p. 351
5. ibid. p. 352
6. ibid. p. 334