Slavery: The world throughout human existence. (Also: cannibalism)


First, my apologies to you Episyllogists for this submission being a day behind schedule. Life’s been busy. I hope it creates enough of a buzz to compensate for its lateness.

In this series of posts so far, I’ve explored a number of ways in which our moral beliefs appear, very surprisingly, to be caused or at least strongly influenced by morally irrelevant factors. My point in posting all these things is not to point out how some other people get things wrong (we all seem prone to these influences) or to present an interesting quirk of human nature to smile at for a few minutes. Rather, I’ve been presenting these things because they seem to point quite clearly to a very serious problem with our moral thinking: not the moral thinking of other cultures, or of mindless people in our culture whom we can look down on, but my moral thinking and yours, personally.

Before I add another item to the pile of evidence today, I’d like to present the main concern in the form of a brief argument:

1. There is ample empirical evidence for the view that our moral beliefs are determined (or, at least, strongly influenced) by morally irrelevant factors.

2. If our moral beliefs are determined or strongly influenced by morally irrelevant factors, then they are untrustworthy.

C. Therefore, our moral beliefs are untrustworthy.

I really don’t want to accept the conclusion of that argument, and I suspect you don’t, either. But how can we rationally avoid the conclusion? This is what I’ve been hoping to discover by making these posts.

Now for today’s discussion. According to a moral view I think we all feel is correct, we humans have learned something about morality over our millennia on this planet. True, our learning has been slow and unsteady; but the general trend has been from an objectively worse understanding of morality to an objectively better one. Two examples of this are commonly cited:

1. Slavery. Throughout much of history, it has been common in more or less all cultures for some people to ‘own’ other people after buying them, defeating them in battle, etc. But we’ve come to see that this is objectively morally repugnant, and this discovery has gradually led to an elimination of slavery (or at least to the fairly universal view that we ought not have slaves).

2. Cannibalism. Many early peoples seem to have killed and eaten other humans, particularly in the context of warfare. A member of the opposing tribe would be captured in some skirmish, taken back to the camp, cooked, and eaten. There is no reason to think that this was considered shameful behavior, and even the Aztecs performed human sacrifices quite openly and avidly. But cannibalism is objectively morally repugnant, and we have gradually come to understand this almost universally. Aside from the possibility of a few isolated holdouts of traditional tribes on the Solomon Islands and in Papua New Guinea, no culture today endorses or practices cannibalism.

Our shifting views on both cannibalism and slavery seem to be examples of objective moral progress. On the other hand, I explained last week that changes in attitudes toward slavery might have to do with our perception of the climate and the demands of industrialization rather than our moral perception. That should have been deeply disturbing news to any believers in reliable moral knowledge, as it was to me! And now, we have cannibalism to consider as well as slavery. Surely, the only plausible reason we would change our minds about the morality of cannibalism would have to be the unavoidable moral wrongness of it. Or would it?

As one begins to contemplate that question, it’s difficult not to be struck by how badly enemy combatants are treated in wars around the world today. The most horrible atrocities are performed on them regularly, and in the end they are generally killed. Is this really a moral improvement on cannibalism? Or is something else at work here?

According to Marvin Harris, our shifting attitudes toward cannibalism and slavery can easily be explained without invoking our knowledge of objective moral facts: one simply has to look at opportunities of caloric intake. It seems that the dietary choices of animals in a given environment can reliably be determined by a mathematical formula whose inputs are: the caloric yield of the available food sources, the calories expended in securing each food source (I.e. in hunting or browsing), and the time between spotting the food source and eating the food. When this same formula is applied to humans, it turns out to be just as predictively successful. Some humans eat swarming insects; others do not. The ones that do have no other food source that yields as many calories after the same amount of time with equal or less energy expended. The fact to note here is that environmental matters of caloric yield determine whether a society condones the eating of insects, and societies that don’t condone it find it disgusting; but when asked, such societies get things backward and believe that the disgust judgment explains the practice and not vice-versa.

OK — so our disgust judgments follow our social eating practices rather than drive them. But so what? What does this have to do with our moral judgments about slavery and cannibalism, say? Surely those judgments are not merely driven by something as morally irrelevant as caloric yield… are they?

Well, Harris applies his same empirically successful ‘caloric yield’ analysis to these two moral topics. First, cannibalism. The tribes who practiced cannibalism were typically on the brink of starvation, and sometimes a little beyond that brink. They lived as hunter-gatherers in environments in which there were few large animals to hunt. Meat would have been a precious commodity to them: a matter of life and death to at least the hungriest members of their tribes. Why kill your enemy on the battlefield and leave his corpse to rot away, when you could march him back to your camp to be eaten? Sure enough, it’s the societies whose caloric situations matched that description who in fact practiced cannibalism. The one large society we know of that condoned cannibalism was the Aztecs. And, perhaps not surprisingly, the Aztecs were also remarkable in that they managed to increase their numbers despite having… no large domesticable animals in the vicinity!

As societies shift from hunting/gathering to farming/animal husbandry, it at last becomes a calorically reasonable proposition to keep captured humans around. Captured humans can help with the farming and other chores. More precisely, in a society in which there is too much work for everyone to do comfortably but the overall available calories would be greater by having more people do the work, it becomes, the ‘caloric yield’ model that works for animals would also predict that those societies would keep captured warriors as slaves rather than eat them.

As societies rise to greater power, it becomes possible to colonize other areas and rely on their regular payment of taxes. And in an industrial society, as I explained last week, it becomes more expedient to replace slave labour with wage labour. All of this can be seen as an extension of the caloric yield model.

So: did our moral repulsion at cannibalism and slavery lead to their decline? Or was it their decline for reasons that had nothing to do with morality that led us to see them as morally abnormal? Sad to say, the evidence seems to support the second option.

18 thoughts on “Slavery: The world throughout human existence. (Also: cannibalism)

  1. The way these cases are presented really managed to shock me (so much that I needed to write here, my apologies for dissapearing for so long).
    That our moral beliefs are untrustworthy is quite unsettling; but isn’t that the case with all beliefs UNTIL you show you have proper evidence? Now, a person might insist the earth is flat because the evidence he has is clear: he can walk around and see that the surface is simply flat. Another person insists God exists because she has had a religious experience. That a person can’t see that slavery is wrong because it’s a practice that is required for economic reasons or because of climate or whatever other morally irrelevant reason doesn’t mean there are no objective moral laws; just as the belief of the flat earth man doesn’t mean there is no objective truth about the shape of the earth.


    • Excellent point, laura, and welcome back! The shape of the planet earth depends upon the brute fact of the shape of the planet earth. Are there, do you think, equivalent moral facts?


    • Laura!!! I’ve missed you. It’s been so long!

      I’m glad you find these cases shocking. _I’ve_ found them very shocking when coming upon and considering them, and it’s refreshing to see someone else here who reacts the same way.

      I agree with you that disagreement and distorting influence don’t necessarily point to relativism. But they do point, I think, to a range of possibilities that are less than desirable.

      You raise a parallel with the shape of the earth. I’d like to explore that. Let’s imagine a time in a science fiction sort of future where most technology is lost and nobody has the ability to determine the shape of the earth. Some people think it’s completely flat, some people think it’s roughly spherical, and some people think that it’s neither flat nor roughly spherical. These three groups argue for centuries but they can’t make progress because they have no means of determining the truth. Meanwhile, all the people in this world eat food from machines: nothing else on the planet is edible. You must either eat the red-coloured food, the yellow-coloured food, or the blue-coloured food: you won’t be able to digest two types of food at once. You can switch your food colour with an effort, but it’s a physically difficult process. Anyway, suppose the people finally figure out that everyone who eats yellow food believes the earth is flat, everyone who eats red food believes it’s roughly spherical, and everyone who eats blue food thinks it’s neither of the two. Whenever people change food colours, they change their beliefs. So now the people know that the food is causing them to have their beliefs.

      I think in that case, the people should conclude that one of the three groups is objectively correct and the other two are objectively incorrect. However, they should also admit that their view is likely wrong. Even though the red group has the correct beliefs, they would have had those same beliefs even if they had been completely mistaken; so their beliefs are not reliable. And if you recognize that your beliefs are not reliable, you should come to suspend judgment on whatever your beliefs are about, no? The same goes for morality, it begins to seem. And that is disturbing.


      • I agree, it’s disturbing. But obviously we can’t afford to stop making moral judgments or assertions about how the world is. Before the three people in your story find out about the foods and their effects, they would have to stop judgment unless they agreed on some sort of parameter that allows them to lean for one of the beliefs more than the others; something like prediction power for scientific theories; the “small” problem is to find that parameter for moral judgments.


  2. It might be interesting to think about an old distinction: brute facts and institutional facts. The shape of the planet earth is a brute fact – it is what it is independent of what minds believe it to be.
    Institutional facts are what make the piece of coloured paper in my left-hand pocket count as a $20 dollar bill. That piece of matter is made up of a certain composition – its brute facts; but it is also a $20 dollar bill because of its participation in a set of institutional facts – a Canadian gov’t, a system of finances, etc.
    Perhaps moral claims are like institutional facts – dependent upon an institutional structure for their meaning and significance.


    • The fact that the piece of paper in your pocket is worth twenty of the eleven-sided coins in your mason jar is an institutional fact. If in 2016 the institutions change and it’s decreed and accepted that that same piece of paper is worth only a twentieth of one of those eleven-sided coins, then the statement ‘The twenty dollar bill is worth twenty loonies’ will become false, though it is true now.

      If moral claims are like institutional facts, then what happens to the truth of statements like ‘Cannibalism is immoral’ if society’s practices change in 2016 or 2116?


    • Interesting! I had a browse, and it looks as though they’re discussing the cannibalism of people who aren’t opposed to being cannibalized.


        • Right! And yet, some people aren’t too comfortable with that, even if they can’t put their finger on why.
          It reminds me of a famous case of a German man who wanted to be an ethical cannibal. He put a call out on the internet for people who might enjoy being killed and eaten. He found someone who was into the idea and took all the legal precautions he could think of, making sure that there was ample evidence that the ‘victim’ was going into the cannibalism willingly and in full knowledge. Then, he videotaped the entire process so that he could keep a record for legal purposes. Nonetheless, as I recall, he found himself in legal trouble.


        • The German man must have been a deranged psychopath. I don’t know HOW one would describe the willing victim!

          There seems to be a difference (of tolerance?) between ancient tribal beliefs and cannibalistic customs, and more modern civilized humans who cannibalized corpses in order to survive. I’m thinking about the Donner Party when they were snowbound and starving in the Sierra Nevada. Who among us would choose to do what they did out of desperation and hoping to survive?


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