Two kinds of psychophysical reduction, part 1: biochemical

by Dave Maier

The relation between mind and matter is a perennial philosophical conundrum for a reason. If the workings of the mind depend too much on the physical material that seems to house it, then it can be hard to see how there’s conceptual room for human agency. On the other hand, if they don’t depend on it at all, then it’s hard to understand why such things as brain injury or the ingestion of this or that chemical substance should have any effects at all, let alone the reliably predictable effects that often result. Something’s gotta give!

We’re certainly not giving up the truths of natural science. However, just as allowing agency to slip the bonds of nature makes a lot of things inexplicable, so does getting rid of it entirely. (Imagine trying to explain, say, the Civil War without even once appealing, even implicitly, to the notion that human beings act on their beliefs and desires, and are thereby subject to praise and blame from others.) The two types of explanation need to learn to live together, as equally valuable tools in our conceptual toolbox. We need to get clearer, then, on how exactly our normative explanations, and our practices of praise and blame, actually play out. What are they good for, and what are their proper domains of application? What happens when we press them too hard, or try to use them for something they’re not designed to do? How can we get them to play nicely with their conceptual colleagues?

Problems result not only when we use normative language like we do the laws and concepts of science (a common error), but also when normative concepts or principles get in each others’ way, which they will even when we’re being careful, because that’s the nature of the beast. (And of course we’re not always careful.)

Let’s start with a look at a widely used principle, applicable not simply in moral contexts but to normativity generally: that “ought implies can.” The point of this principle is fairly intuitive. [Note: as a speaker of American English, I will be using “ought” and “should” interchangeably here (my apologies to the Queen).] It is at least very often true that it makes no sense to criticize someone for failing to do something which is impossible. On the other hand, there are many different potentially relevant senses and degrees of (im)possibility.

At the one end, we find the pure instances of this principle. I can neither trisect the angle nor disprove Stokes’s Theorem, as these are mathematical impossibilities. I cannot bowl a 400 game (the scoring only goes up to 300). I cannot checkmate my opponent at move 1. I cannot stip the brenclonst (that makes no sense at all and is not even English). I cannot leap ten feet into the air (on Earth anyway). To chide me for these failures would be perverse.

Things get a bit wonkier, however, almost immediately. I cannot prove Stokes’s Theorem. I cannot hit a major-league curve ball. I cannot write a villanelle. I cannot charm my way into a secure facility. Here it matters who we’re talking about and under what circumstances. You shouldn’t criticize me for these things, but in a math student or a major-league baseball player or a spy the relevant failures may indeed be blameworthy. Indeed, if I can’t do something I should be able to do, then this can seem pretty much the same, or at least provoke pretty much the same criticism, as my not doing something I should do (or, conversely, doing something I shouldn’t).

Yet our principle may still hold, in a sense. If someone can’t hit the curve ball, maybe he should be sent back to the minors, since a major-leaguer ought to be able to hit breaking pitches to justify his roster spot. But zoom in closer and the inability, while still unfortunate, doesn’t match up with blame quite the way it did before. If this guy goes up to hit with the game on the line, and Brandon Workman strikes him out with that filthy 12-to-6 curve ball of his, whose fault is that? The player’s, proximately; but most of the fans’ ire would, in that situation, fall rightly on the manager, who knows the guy can’t hit breaking pitches and should definitely have pinch-hit for him then. Of course our guy struck out; he couldn’t help it. What did you expect?

Push it farther, though, and blame will seem required no matter what. Or will it? Here’s where things get wonkier still, as other principles and/or theoretical commitments start to jostle for position. In legal contexts, for example, legal principles will start to crowd out more purely conceptual ones, but it’s still interesting to see how the latter are still hanging in the background pulling our strings. Take this case. The New York press has been reporting recently about a young man who apparently killed his father after having had his weekly living allowance cut to $300 (from $1000), and is being criticized for it in a very public way – he is on trial for murder.

His lawyers are mounting an insanity defense: he couldn’t help it. This seems at first to be a straightforward, and indeed appropriate, application of our principle. Mental illness can clearly affect one’s capacities in any number of relevant ways. If someone suffering from schizophrenia or the like stabs someone, believing himself to be acting in self-defense against abduction by alien lizard-men, while we will certainly wish to constrain that person’s liberty in order to prevent further harm, we will also most likely exculpate him morally, since “he didn’t know what he was doing.”

In our case, though, the (claimed) inability in question is not that the defendant couldn’t help firing the fatal bullet, but instead, as the Times puts it, that he was “imped[ed] … from comprehending that [he] committed a crime or from knowing what [he] had done was morally wrong.” Yet the judge has already ruled him to be “mentally competent” in the sense that “he can understand the proceedings against him and is able to help with his defense.” One might worry that understanding that one is on trial for a crime based on what one has done, on the one hand, is awfully similar to understanding on the other that what one has done is, in general, a crime. In any case, as it happens, even if he is “able to help” with his defense, he has not in fact done this, having for weeks been “reprimanded … for spouting random objections and nonsensical legalese” by the judge, and is now only occasionally attending the trial. 

How should the prosecution respond? What actions might show our man to be culpable after all? Planning ahead, for example, is sometimes taken as a sign that someone “knew what he was doing,” but that seems not quite the same thing. Taking pains not to be discovered does not seem to show this either, as this may also simply be thought a practical rather than a moral matter. Our concepts are slipping out of our control.

Even knowing right from wrong itself is oddly ambiguous. It might mean that one has no conception of right and wrong at all; or instead that one is (supposedly) incapable of recognizing this or that action as the morally wrong action that it is. But the latter just sounds like ordinary moral disagreement. What distinguishes that from a full-blown lack of capacity in the relevant (i.e. potentially exculpatory) sense?

The cases of psychopathy and sociopathy are telling here. These are “mental illnesses” if anything is; yet such people are indeed (as I understand it) entirely capable of distinguishing right and wrong. They know they’re acting wrongly; they just don’t care, and thus they earn our moral disgust (and correspondingly harsh punishment). But if we think of their characteristic inability this way – as one of failing to see the immorality of an action as a reason not to commit it – how is that not just as much a debilitating condition as any other? Restrict their freedom on prudential grounds, but save your contempt for people with the morally relevant capacities.

But now, toward this end of the scale, our moral judgments are threatening to crumble into nothing. Consider the worst of the worst, someone who commits vile crimes without even the “excuse” of sociopathy we just saw. An incorrigible child molester deserves our moral outrage if anyone does. He knows full well that his actions are immoral, and unlike the sociopath, he may try to resist his horrific urges and regret his actions when he fails to resist. This is moral failure at its worst. Yet even here, in our justified outrage, we hear the disturbing, muffled echo of our original thought: he couldn’t help it.

We are now approaching the territory of biochemical reduction. To see how, let’s turn to another example. While in the grip of their addiction, drug addicts can act as reprehensibly as anyone. They lie, cheat, steal, manipulate, and worse. That they manifestly “cannot help” so acting has led some to classify addiction as a disease rather than a moral failing. This does not seem quite right, however, not least since it does not distinguish between the biological basis of behavior while in the grip of addiction, on the one hand, and that of being genetically disposed to become addicted to this or that in the first place, on the other. There are more subtle and detailed accounts available.

One of these is to be found in Marc Lewis’s Memoirs of an Addicted Brain. Nearly every chapter tells the story of the author’s abuse of a new drug (and there are quite a few chapters), followed by a (very) detailed description of the (many) parts of the brain, their typical functions, and the ways in which this chapter’s drug affects them. It’s a clever and instructive way to organize the book, but if you’re not a med student you will quickly lose track of the differences between the ventral tegmental area and the orbitofrontal cortex. Let’s go right to his account of the key feature of addiction from our perspective: the inability of the addict to resist temptation, or, that is, the sense in which he “couldn’t help it.”

The human brain’s most respected achievements – judgment and choice, planning and self-control – rely on the activation of an arch of tissues right in the middle of the prefrontal cortex: the anterior cingulate cortex (ACC). The dorsal anterior cingulate cortex, or dACC for short, is in charge of choice, self-monitoring, and the resolution of conflicting goals. The dACC is where context and judgment come together to create the will, that beam of self-direction that makes it possible to choose consciously and act morally. The dACC activates its neighbours to create the fulcrum of decision making, the keen blade of intelligence itself. … Should I or shouldn’t I? … [T]he dACC chooses what to do from the possibilities held in working memory [nearby]: Here are my options, now what’s the plan? [244]

We [that is, Lewis’s readers] have already seen how in addicted brains, the options for action are both limited and skewed. The desire for the drug (at this point, for Lewis, that’s morphine) has been so ingrained by habit that it simply crowds out the other options. How this works in the brain, though, is that even when the addict (or the executive function, residing in the dACC, which evaluates action rather than desire) recognizes the better option and chooses to resist relapse, this is not the end of the story: the other parts of the brain keep sending their favored option (drugs! now!) back to the dACC for another decision. At first, this doesn’t sound like a problem. Why wouldn’t the same thing just happen again? After all, it’s not like things have changed since the last time the decision was made. In biochemical terms, though, here’s what’s really going on:

In doing its routine chores, the brain uses up a fantastic amount of energy – more than the rest of the body combined. … When the dACC has to keep working to control an impulse, one that keeps recurring, or just won’t go away [that is, as it would in non-addicted brains, most of the time anyway], it uses up its supply of energy. It can’t replenish its store of neurotransmitters. It gets tired. Very much like a muscle. … Just a simple physical action, maintained too long, soon exhausts the resources that made it possible. [246, emphasis in original]

Addicts thus lose “the mental muscle tone for self-direction, for resolve, for strength of character, and for decency itself.” His conclusion sounds dire:

The psychological realities of diminished choice and narrowed interests – those well-known attributes of addiction – are precisely paralleled by the neural reality of reduced flexibility in synaptic traffic patterns. But here’s the thing: the brain doesn’t really parallel the mind. That would be a misnomer, a poetic approximation. It’s the other way around: the mind parallels the brain. The way the brain works – the biological laws of synaptic sculpting and neurochemical enhancement, each reinforcing the other – are what constrict the addict’s mind, his behaviour, his hopes, his dreams. … I wish this were just an exercise in biological reductionism, or neuro-scientific chauvinism, but it’s not. It’s the way things really work. [228]

This talk of “reduction” might indeed sound conceptually drastic; and yet as we’ve seen, Lewis is perfectly willing to use the language of morality and agency, apparently literally, in discussing the functions of the dACC. Indeed, how could he avoid doing so? Without them he has no explanation of anything worth calling human behavior. In fact Lewis’s own disappointment is not that of the philosopher backed into a conceptual corner, forced to give up a treasured intuition, but instead that of the addiction researcher (and addict) hoping that maybe the right attitude, say as acquired in rehab, will be enough to foster sobriety and self-control. Instead, we might as well try to talk ourselves into being able to hold up a heavy weight for an hour.

Conceptual reduction of this sort threatens agency because a complete causal chain of events can seem to leave no room for “freely willed” actions, the only things which can possibly deserve our moral condemnation. This is the natural implication of this application of our principle: if you can’t do something, then it can’t be something that you ought to do. Yet our purpose was not to withhold blame in such cases, but instead to understand it. Indeed, as we noted above, not being able to do something you should be able to do can be just as objectionable as actually doing something you shouldn’t. Most of us have that reaction as well to defense lawyers’ sob stories about a killer’s deprived childhood. If a mobster kills my entire family in cold blood, I don’t care if his mommy didn’t hug him enough – he’s still a monster.

This may tempt us to reject the biochemical explanation as simply not capturing the moral facts on the ground. Still, as I will argue in the second part of this post, this is the sort of psychophysical reduction with which we may yet be able to make conceptual peace. The other, which involves not biology but physics, will be another story entirely.