[this is a post in two sections, the first by my friend Julia Gailef, a journalist, the second being my response, below]

I hope Massimo won't start regretting his generous invitation for me to co-blog with him (hi readers! great to be here!) if I kick things off by immediately and publicly disagreeing with him. He and I have been having a debate on moral philosophy for the last few weeks, and after the twentieth iteration of the same arguments we decided it makes sense to invite you all to weigh in, at the very least because we're tired of the sound of our own voices by now. Massimo asked me to lay out the debate, and then he'll follow up with his own post next week.

So, I agree with Massimo that moral reasoning is possible, given a set of initial axioms. (Axioms are the starting assumptions on which all of your moral judgments are based, like the concept of certain fundamental rights, or tit-for-tat justice, or protecting individual liberty, or maximizing total happiness). Where I disagree with him is over his belief that it is possible to use scientific facts to justify selecting one particular set of initial axioms over another.

Roughly speaking, Massimo starts with biological and neuroscientificfacts such as "Human welfare requires things like health, freedom, etc." and "Humans are wired to care about each other's welfare," and from these he derives the conclusion, "Therefore, it is moral to act in a way that increases those things which are necessary for human welfare." In my opinion, this is an example of what is sometimes called the naturalistic fallacy: telling me scientific facts doesn't tell me how to act on those facts, and the alleged point of moral principles is to tell me how to act. Science can tell me that if I want to make other people happier, then treating them in certain ways -- giving them health, freedom, and so on -- will accomplish that goal. But science can't tell me whether making other people happier should be my goal.

Alternately, you could use evolutionary biology and neuroscience to argue that being kind to others is the best way to maximize one's own happiness, thanks to the way our brains have become wired over the course of our evolution as social animals. I agree that there's some truth to this claim, but I deny that we can derive any moral principles from it -- it implies only an appeal to self-interest that happens, through lucky circumstances, to have positive consequences for others. (Furthermore, if your moral imperative takes this form, the implication is that if for some reason I were wired differently, then being unkind would not be immoral.) 

The difficulty of deriving facts about how people ought to behave from facts about how the world is was most famously articulated by David Hume in his Treatise of Human Nature (1739):

"In every system of morality, which I have hitherto met with, I have always remark'd, that the author proceeds for some time in the ordinary ways of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when all of a sudden I am surpriz'd to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, 'tis necessary that it shou'd be observ'd and explain'd; and at the same time that a reason should be given; for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it."

This is called the "is-ought problem", or sometimes "Hume's Guillotine" (because it severs any connection between "is"- and "ought"-statements). My understanding is that Hume is generally believed to have meant not just that people jump from "is to "ought" without sufficient justification, but that such a jump is in fact logically impossible. There have been a number of attempts to make that jump (here's a famous one by John Searle), though I've found them pretty weak, as have other people with much more philosophical expertise than me.

With that in mind, I can't see any way in which a claim of the kind Massimo is making -- "doing X increases human welfare, therefore X is the moral thing to do" -- could logically hold, unless you're simply defining the word "moral" to mean "that which increases human welfare," in which case the statement is tautologically true. But I'm not sure what we gain by simply inventing a new word for a concept that already exists. 

Fortunately, even though I think the blade of Hume's guillotine is inescapably sharp in the philosophical world, I don't think it has the power to sever much in the real world. Because, thanks to some combination of evolutionary biology and social conditioning, I do enjoy being kind, and I do want to reduce other people's suffering -- and I would want to do those things even without a rational justification for why that's "moral." And I believe most people would feel the same way.

But if someone didn't care about other people's welfare, I couldn't accuse him of irrationality. He would be committing no fallacy in his reasoning, nor would he be acting against any of his own preferences. (If he wanted to increase human welfare and yet he knowingly acted in a way that reduced human welfare, then I could legitimately call him irrational.)

Massimo, I believe I've represented our disagreement accurately, but please correct me if I haven't! *thwack* Ball's in your court!

>> Massimo's response <<

I want to thank Julia, our new regular contributor to Rationally Speaking for an honest and clear presentation of her doubts about the possibility of moral philosophy. Judging from the comments to her post, a good number of our readers seem to agree with her position, which is essentially one of moral skepticism, inevitably leading to a morally relativistic position (although she says that she gets her own moral sense from the way she is wired as a social primate, she also admits that she could not honestly blame someone who acted differently and had no inclination to be kind to others or help human welfare).

First off, then, let me suggest that I don’t think anyone is really a moral relativist, not even Julia. Moral relativism, or moral skepticism, is akin to skepticism about the existence of the world: it may be ultimately impossible to conclusively refute in an air-tight logical manner, but no one actually lives in this way, and no one really believes it. (Bertrand Russell once famously said that he wished that all those people who deny the existence of a wall would get into a car and drive straight into the wall at a speed proportional to their lack of belief in the existence of said wall. I am not aware of the actual experiment ever having been carried out, but of course, as any good skeptic knows, even if the people in the car all died this would not prove the existence of the wall — though as Russell remarked rather drily, we would get rid of a number of bad philosophers... But I digress.)

Second, although this discussion is fascinating and I think useful for our readers, neither Julia nor I can possibly hope to settle in this context a complex issue that defines a whole field, that of metaethics, or the rational justification of ethical thinking. Despite the fact that both Julia and several of our readers are dismissive of philosophy as a type of inquiry (a rather curiously anti-intellectual position, in my opinion), I urge the rest of you to read this excellent introductory essay in the Stanford Encyclopedia of Philosophy to begin to dig deeper.

All of the above said, let me finally get to the meat of Julia’s essay. Let’s start with this business of “axioms.” During one of our discussions over dinner I brought up the idea of axioms in ethics to refute a point that moral skeptics never fail to bring up, despite its obvious weakness: ethical reasoning is fluff because there are no moral empirical facts. But the skeptics curiously seem to miss an obvious case study which reveals the hollowness of their position. There are in fact well established and unquestionably serious areas of human endeavor for which “facts” are irrelevant. Consider the entire field of mathematics, for instance. I hope no one here will suggest that mathematical reasoning is arbitrary or without foundations. And yet mathematical theorems are valid / invalid regardlessof any empirical fact abut the world.

This example should not be taken lightly, because it is a devastating objection to the moral skeptic, although we need to understand exactly what I am saying here. I am not suggesting that ethics and math are on the same footing, far from it. Rather, I am demonstrating beyond doubt that lack of empirical facts per se in no way precludes the ability of the human mind to reason rigorously about certain entities. It is an interesting philosophical (imagine that!) discussion whether mathematicians discovermathematical truths or they invent them, but in either case such inventions or discoveries are both rigorous and non-arbitrary.

It is of course true that the early 20th century quest for an ultimate, self-contained logical foundation for mathematics failed (see Russell and Whitehead’s Principia Mathematica) and was ultimately shown to be a mirage by Godel with his incompleteness theorem. Still, no one would argue that because of that mathematics is an arbitrary castle built on clouds. (Indeed, if we take that sort of skeptical position, then even Julia’s much touted empirical science gets into deep trouble, as rather ironically shown by Hume himself with his problem of induction.)

Indeed, I think that ethics is in some sense on a firmer foundation than math, because we can use empirical data from evolutionary biology andcognitive science to provide us with relevant empirical facts in which to ground our enterprise. As I will argue in a minute, this is not at all an instance of Hume’s naturalistic fallacy.

To begin with, I define ethics as that branch of philosophy that deals with the maximization of human welfare and flourishing. I’m sure this will disappoint Julia and others, but I simply don’t understand what else they might possibly wish to include in a talk about ethics. Neither Julia nor I believe in morality as imposed by a god, for a variety of reasons, including the fact that there is not a shred of evidence in favor of the existence of any gods, but more importantly because of the decisive (again, philosophical!) argument known as Euthyphro’s dilemma, in which Plato showed that gods are simply irrelevant to the question of morality.

So yes, for me morality is neither arbitrary (the relativist position) norabsolute (the typical religionist position, though Kant also famously attempted to arrive at a logically necessary ethics via an entirely secular route — and failed). Rather, I think of morality as something that makes sense only for human beings and other relevantly similar species. By relevantly similar, I mean social animals with brains complex enough to be able to reflect on what they are doing and why they are doing it (that is, being able to philosophize!). As far as I know, Homo sapiens is currently the only such species on planet Earth, though of course there may be others elsewhere in the cosmos.

By definition, then, something is moral in my book if it increases human welfare and flourishing (I am leaving aside for the moment the issue of animal rights, which would be an unnecessary distraction at this point. Interestingly, consequentialists like Peter Singer have tackled that problem, and Julia presented herself to me once as a consequentialist — apparently without realizing that a moral skeptic cannot also coherently endorse a particular school of ethics. For the record, I incline toward virtue ethics.)

It is at this point that Julia accuses me of committing the naturalistic fallacy, that is of deriving an “ought” from an “is.” There are several issues to be considered here. First, contrary to what Julia maintains, it is not at all clear that Hume argued that the is/ought connection is impossible, he may simply have been saying that if one wishes to make that connection the project has to be pursued by explicitly unpacking how said connection works or can be justified. Second, of course, as much as I myself love Hume, I don’t think the guy was infallible, and generally speaking invoking authority truly is a logical fallacy.

To be as clear as possible, then, I define as moral an action that increases human welfare and/or flourishing (and yes, I’m aware that the latter two also need to be discussed and unpacked, but this is a blog post, not a treatise), and then ask biologists and cognitive scientists to provide me with some empirical points of reference so that my concept of human flourishing is based as much as possible on the so highly valued empirical data.

Here is where Julia makes a subtle, but revealing, shift: she writes that “science can tell me that if I want to make other people happier, then treating them in certain ways — giving them health, freedom, and so on — will accomplish that goal. But science can't tell me whether making other people happier should be my goal.” But ethics is not about what an individual may or may not want, it is about the species as a whole (and possibly beyond, see my comment on Singer above). Julia of course may reject the idea of behaving herself so as to increase human flourishing, but then she is by definition acting immorally (or at least amorally). She may shrug her shoulders and keep going with her life, of course, but most of us are going to think of her as immoral (she isn’t, by the way, she is one of the nicest people I’ve met).

What I’ve got so far, then, is a working definition of morality and some empirical evidence (from science) of what helps human beings flourish. Why do I need philosophy? Because biology provides us only with a very limited sense of morality, an instinct that there are right and wrong things. But that instinct was shaped — slowly and inefficiently — by a blind natural process that simply maximized survival and reproduction. Once human beings became able to reflect on what they were doing they immediately developed an enlarged sense of flourishing that is not limited to personal safety, food and sex. We also want to enjoy life, be free to explore opportunities, to speak our mind, to admire art, to pursue knowledge, and so on.

Our instincts become a less and less reliable guide when the circle of flourishing is thus enlarged. For instance, it is a universal moral intuitionamong human cultures that randomly killing members of your group is bad (psychopaths, or to put it as Julia does, people with a different wiring, are not exceptions, they prove the rule: we put them away whenever we encounter them). But natural selection probably also bred into us an instinctive distrust of outsiders. It has taken thousands of years of moral progress (not an oxymoron!) to slowly realize that there is no rationally defensible distinction between in-group and out-group, which means that we need philosophical reflection to build on our natural biological instinct and come up with the humanity-wide rule that it is wrong to randomly kill anyone, regardless of which group s/he happens to belongs to as a matter of accident of birth.

To summarize, then, I think that:

1. The objection that moral reasoning is not based on empirical facts is irrelevant, since there are other non-arbitrary human endeavors that are also so characterized and yet we do not reject them on those grounds(mathematics, logic itself).

2. I define ethics/morality as concerned with exploring the sort of behaviors that augment human (and possibly beyond human) welfare and flourishing. Since this is a definition, it cannot be argued for, only either accepted or rejected. And yes, definitions are tautologies, but they are nonetheless very useful (all of math can be thought of as a tautology, and so is every single entry in a dictionary).

3. Some empirical facts from evolutionary biology and cognitive science inform us as to where and why we have a moral instinct to begin with, and also about what sort of behaviors do in fact increase human flourishing. It is because of this that I can confidently say, for instance, that genital mutilation of small girls is wrong regardless of which culture practices it and why.

4. To move beyond the narrow sense of flourishing that generated our moral instincts we need to be able to reflect about these issues in a rational and empirically-informed manner. That is, we need to do science-informed philosophy (or what I call sci-phi).

One more thing: I really don’t think Hume would be upset with any of the above, and I believe he would invite me over for a meal (he enjoyed dinner parties) to amicably explore our differences of opinion. As he famously put it: “Truth springs from argument amongst friends.”