Your Brain and You

Christof Koch recently reported on a grim little organism, Toxoplasma gondii. This one celled protozoan reproduces sexually, but only in cat intestines. Mammals that encounter cat feces can become infected with the offspring. The eventual result is an attack on the host’s brain that reduces its aversion to the smell of cats. That’s bad news if you’re a small rodent. From T. gondii’s point of view, however, this is a great strategy for getting itself into a cat intestine, where the cycle can begin again.

There are several lines of reflection that knowledge of this organism may trigger. The one that intrigues me the most is that it may provide evidence for resolving a conundrum that seems at first sight to be irresolvable.

The conundrum can be introduced through a fact commonly reported by beer lovers – namely, that they did not like beer at all when they first tasted it. Many readers will be able to think of parallel examples with other drinks or foods. The reversal can go in the opposite direction, too. I used to like licorice, and also lobster, so much that I overdosed on them, with strikingly unpleasant results. Immediately afterward, I detested these foods, and I avoid them to the present day.

The conundrum is a question about what happens during this kind of reversal. Is it (A) or (B), or, perhaps, some combination of them?

(A) What happens after consuming the item (alcoholic euphoria in one case, nausea in another) causes changes in your brain that makes the item taste differently. For example, you still don’t like the taste that beer produced in you when you first had it in your mouth, but now beer in your mouth no longer produces that taste. It produces a different one that you like better.

(B) What happens after consuming the item causes changes in your brain that alter your evaluation of the taste. For example, beer in your mouth produces exactly the same taste it did the first time you sipped it. It’s just that now you like that taste, whereas before you didn’t.

The problem is that it seems that any case of reversal could be equally well accounted for by either of these views. So, it seems that they are different views, but that nothing could count as supporting one more than it supports the other.

That situation is deeply troubling to some philosophers. A view that was very popular in the mid-Twentieth Century, and still not completely dead, held that there could not even be a difference in what two claims meant, unless it was understood how some conceivable evidence could count as supporting one of them better than the other. If that view were right, and (A) and (B) are equally good at accounting for all possible evidence, then the appearance that they are different accounts must somehow be an illusion.

T. gondii helps us untie this knot. That’s because of three facts that Koch reports. First, infected rodents do not show abnormalities in their sense of smell of other things. More importantly,

     “the density of cysts [housing T. gondii] in the amygdala is almost double that in other brain structures involved in odor perception. Parts of the amygdala have been linked to anxiety and the sensation of fear.”

And,

     “the genome of T. gondii contains two genes related to mammalian genes involved in the regulation of dopamine, the molecule associated with reward and pleasure signals in the brain, including ours.”

While these facts do not rule out some difference in how cat urine smells to infected versus uninfected rodents, they offer more support for a view like (B), i.e., for the idea that infected rodents may smell cat urine just as before, but no longer react to it with fear (and may even find it somewhat pleasant). So there is, after all, a case in which some evidence counts more in favor of one of these views rather than the other.

By the way, many humans are also infected with T. gondii. Effects are not definitively established, but there are suggestive connections between such infection and psychiatric diseases and risky behavior. Hence Koch’s title: “Protozoa Could Be Controlling Your Brain”.

[Koch’s article is at http://www.scientificamerican.com/article.cfm?id=fatal-attraction&WT.mc_id=SA_CAT_MB_20110518 . Reversals have been discussed in D. C. Dennett, Consciousness Explained (Boston: Little, Brown & Co., 1991) and by me in Understanding Phenomenal Consciousness (Cambridge: Cambridge University Press, 2004).]

Sam Harris’ The Moral Landscape: How Science Can Determine Human Values is a book I admire for attending directly to our dependence on our brains and working out the consequences of that dependence – consequences for how we think about ourselves and our mental capacities and, of course, how we should think about our values.

Harris has achieved a style that is highly readable while giving full recognition and fair treatment to the complexities of the topics he considers. These range from the universality of moral judgments to issues regarding the interpretation of brain scans. (His discussion of the latter on pp. 220-222 is invaluable.)

Harris’ subtitle announces a contentious claim. I believe that in arguing for this claim, Harris goes too far. However, I also think he doesn’t need this excess to sustain the main point of the book. I’ll explain both points.

The excessive claim is that values are facts. That means: statements that something is good or bad, right or wrong, ought to be done or ought not to be done, are factual statements discoverable by scientific means.

There is a long tradition that asserts otherwise. Here are two expressions of the view that Harris is opposing.

      No description of the way the world is (facts) can tell us how we ought to behave (morality). – David Hume’s view, summarized on Harris’ p. 10.

      Science is about facts, not norms; it might tell us how we are, but it couldn’t tell us what is wrong with how we are. – Jerry Fodor’s view, quoted on Harris’ p. 11.

Harris, in contrast, describes a scientific account of human values as “one that places them squarely within the web of influences that link states of the world and states of the human brain” (p. 13). He says the divide between facts and values is “illusory” in several senses. He holds that “Whatever can be known about maximizing the well-being of conscious creatures – which is, I will argue, the only thing we can reasonably value – must at some point translate into facts about brains and their interaction with the world at large” (p. 11).

The argument behind Hume’s view, which prevents me from agreeing with Harris here, rests on the intuitive idea that your argument can’t be a good one if your conclusion asserts something about a topic you didn’t mention in your premises. For example, if you haven’t mentioned hyenas in your premises, you can’t draw justified conclusions about them. Even if you’ve said a lot about African mammals, you’re not entitled to conclude anything about hyenas unless you have a premise that says hyenas are African mammals.

And similarly, you can’t give a cogent reason for a value judgment – a judgment that something is good, or right, or ought to be done (or their opposites) – unless your premises say something about what is good, or right, or ought to be done (or their opposites).

That would be no obstacle if some value judgments could be known to be true by observation. But there is no sense organ for observing values, and no observational science of values.

So, value judgments that we can support must be supported by arguments, and if these are good arguments they must already assume some premise about values. Ultimately, therefore, if we have reasons for any of our values, we must have some value judgments that are not supported either by reasons or by observation. But science rests on observation and reasoning. So some of our value judgments are not supportable by scientific means.

But Harris does not need to disagree with this point. The rest of what he says in The Moral Landscape fits very well with accepting both Hume’s fact/value distinction and the reason just given for it. All we need to do is to distinguish the basic values that constitute well-being from less basic values that are believed – rightly or wrongly – to promote well-being.

The key point is already visible in the last remark quoted from the book. Suppose we agree on what constitutes the “well-being of conscious creatures” and that in actual fact we agree in positively valuing this well-being. Then we can turn to our sciences to tell us about better and worse ways to get it. There will be genuine, scientifically discoverable facts about what promotes well-being and what interferes with it.

This role of science is not in conflict with the view that scientific methods are not suited to tell us whether, for example, “Chronic hunger is bad” is true. Sociological science can, of course, tell us whether avoidance of hunger is valued, i.e., whether people agree that chronic hunger is bad. But Harris would be among the first to insist that finding out the facts about what people agree to is not the same thing as finding out what is true.

The right and wrong answers to moral questions that Harris wants science to provide can be found, provided we have wide agreement on what we most basically value. It may seem that we don’t agree in basic values, because moral questions are notorious for provoking disagreement. The response that is implicit in Harris’ book is this: We do in fact agree on many aspects of what constitutes well-being. Then we can use our sciences to distinguish between successful and unsuccessful ways of getting it. One result of applying our sciences is learning that some of our less basic moral judgments are wrong – objectively wrong. To say that a moral rule is wrong means: If people follow that moral rule, they will frustrate the achievement of the most basic values that constitute well-being.

Harris makes a plausible case for the widespread acceptance of his idea of well-being, and I predict that most readers will agree with him. Near the end of The Moral Landscape, he raises several concerns about the possibility that what constitutes well-being might be different for different people, or different for people in different cultures. Here is his reply:

We have all evolved from common ancestors and are, therefore, far more similar than we are different; brains and primary human emotions clearly transcend culture, and they are unquestionably influenced by states of the world . . . . No one, to my knowledge, believes that there is so much variance in the requisites of human well-being as to make the above concerns seem plausible.

In sum, a structure that would fit all of Harris’s statements except those where he explicitly rejects the fact/value distinction is this:

(1) There are important basic values (e.g., avoidance of hunger, cold, pain and other miseries, enjoying social relations, satisfying curiosity) that humans share. That we do share these values is a sociologically establishable fact, but the truth of the statements that such things are valuable is not something science can underwrite.

(2) Science can help us achieve more of what we basically value (and avoid more of what we basically disvalue).

(3) Many moral judgments (both those held by individuals and those built into social or religious institutions) are not expressions of basic values, but are instead intermediate level rules. These rules may or may not actually conduce to our well-being. Science can provide good, objective reasons for adoption of genuinely helpful rules and practices, and good, objective reasons for abandoning rules and practices that conflict with satisfying our basic values.

Harris seems to think that the fact/value distinction has to be rejected if we are going to be able to use science to help achieve well-being. This is not so. My drift here has been that we can accept all three of these key points while recognizing that the truth of “Chronic hunger is bad” (for example) is not something that scientific methods are relevant to establishing. The power of this truth comes not from scientific credentials, but from the fact that we all share this value judgment. And the strength of The Moral Landscape lies in its applying what we have learned from science to the evaluation of actually held intermediate level moral beliefs.

[The book under discussion is Sam Harris, The Moral Landscape: How Science Can Determine Human Values (New York: Free Press, 2010).]