The philosopher, Daniel Dennett, of Tufts University, Boston, died last week, aged 82. Dennett was openly contemptuous of the concept of dualism, the idea that mind and brain are of different orders of nature. His goal was to build a biological account of mind, to replace the "green slime" of mentalism. "Somehow," he said, "the brain must be the mind.” Needless to say, the devil lay in the details of "somehow." When it came time to insert the last link in the causative chain between neuron and mind, he opted for a "virtual machine." That is, he had to rely on an insubstantial, unlocalised, causally-efficacious entity that is not subject to the laws of the physical realm, and for which he offered no provenance, no medium, and no governing laws. It doesn't get much more dualist than that. On this basis, I say that his life's work failed.

I contacted him some time ago to ask for a comment on this critique but got a very dismissive response. I've since heard that somebody else referred him to the video of a talk I gave last year to the Philosophy Department, University of Queensland, which gives more detail. His response was: "The fellow (i.e. me) doesn't know what he is talking about." I understand he wasn't well at the time but that's not how it's done. He could have asked one of his many adoring fans to respond on his behalf but he didn't, so we'll have to wait and see where the debate goes. At present, I stand by my conclusion: the late Daniel Dennett was a closet dualist. To complete his functionalist account of mind, he relied on a frankly dualist model, one which lurches perilously close to magic. His goal of a reductive account of mind joins the long list of failed positivist attempts to write the mentality out of the mind (when it's put like that, it's patently absurd but they're doing it, not me).

What's the significance of this for psychiatry? Just this: modern biological psychiatry is based on the notion that "somehow," the mind will reduce to the brain. A full account of the brain will give a full account of the mind with no interesting questions unanswered. Perforce, that includes mental disorder. The collapse of yet another attempt to write an antidualist "theory of mind" means that mainstream psychiatry is practising without a theoretical warrant. The hostile antidualism bred by the positivist urge in philosophy and science is on its last legs.

A reader asked: "Your thoughts on anxiety linked to bipolar are curious. Have you written directly on this? On the surface the two ways of feeling/existing/experiencing the world seem very different. Any reading recommendation or link to further reading would be appreciated."

This is actually a big question that goes to the heart of the debate over the nature of mental disorder, but remember that, for the overwhelming majority of psychiatrists in the world, there is no debate. The issue was settled in 1980 with the publication of DSMIII when, on zero convincing evidence, psychiatry was booted into the biological camp. Samuel Guze, who was one of the most influential architects in psychiatry's biological epiphany, said: " ... there is no such thing as a psychiatry which is too biological".1 He offered no proof, but that Brave New World trope still dominates the ideological echo chamber that passes for psychiatry's collective intelligence.

I disagree totally with the notion that the mind reduces to the brain; my case will be set out a the forthcoming volume on theories in psychiatry. However, it's not enough to disagree; Buckminster Fuller (1895-1983) warned: "You never change something by fighting the existing reality. To change something, build a new model that makes the existing model obsolete." That's been done2; a rational case for the psychological causation of major mental disorder exists. All that remains is for mainstream psychiatry to acknowledge that education is not just indoctrination and to read it. However, asking your typical psychiatrist to read something on the nature of mind is asking too much: they don't, partly because they don't believe they need to, that it would be silly, but also because most of them can't. The idea that in the head there resides an infinitely complex thing called "mind" cannot be grasped.

Putting that aside, the notion that linking anxiety to bipolar disorder is "curious" rests on the major assumption built into DSMIII, and in every version since. This says that mental disorders are distinct categories, just as dogs and cats are distinct categories, and can be sorted reliably into their groups by ticking a few boxes. First objection: this is not a scientific claim. Without exception, mental constructs or parameters distribute dimensionally, not categorically. What this means is that any element of mental life, be it intellect, happiness/unhappiness, shyness, suspicion, aggression and so on, does not form a distinct and separate group from normality. Every mental parameter runs smoothly from normal to abnormal, just as measures such as height and weight range from normal to abnormal with no cut off. To announce that a mental state is "abnormal" is a value judgement, not a scientific decision.

Why would anybody bother trying to build a classification of mental disorder on a false premise? Because they desperately wanted it to be biological, as Guze said. As good positivists (but without having a clue what that meant2), they had to write the mind out of psychiatry because science can't cope with unobservables. If psychiatry wanted to be a serious science like the rest of medicine, they had to replace the unobservable mentality with observables, such as genes and neurotransmitters. The hope was that the core symptoms of each mental disorder would map directly to a specific defect in the genome. Subsequently, drugs could be developed to target each genetic defect, thereby curing all mental disorder. It's a bit like the change that overtook medicine when Louis Pasteur developed the "germ theory" of illness: for each illness, people hoped to find a specific germ that could be managed. Except there wasn't, and in the intellectual space he opened grew the immeasurably complex and far-reaching science of immunology that makes sense of the loose ends of infections (and opens up whole new vistas of unimagined science, an infinita scientia).

For psychiatry, the intellectual appeal of the search for the elusive "schizococcus" (modern version: the schizogenic single nucleotide polymorphism) is obvious, an effortless psychiatry in which the complexity of human mental life is reduced to a few lines on a laboratory report. It also meant eager young psychiatrists could make their names by "discovering" a particular genetic defect, and drug companies could make their fortunes with their concoctions, along with a few discreetly-placed kickbacks. It's pie in the sky, of course, but that was the covert agenda.

Without that agenda, nobody would bother with the idea that, say, anxiety and depression are unrelated, as a paper published last week shows.3 Working with Joanna Moncrieff in London, John Jureidini and his group in Adelaide reanalysed data from a very influential study on antidepressants in adolescents. They showed that the patients and their carers regularly guessed whether they were prescribed the active drug (fluoxetine, or Prozac) or a placebo (inactive tablet). Their guesses influenced the outcome: if they thought they were getting the active drug, they got better quicker than if they thought they were on the placebo, regardless of what they were getting. Just as the discovery of germs led to the huge science of immunology, this result demands that psychiatry analyse the role of expectation in the causes of mental disorder. And, despite all the hopes for a biological psychiatry, this means taking the patient's belief system into account, which is pure mentalism. Tough luck, all you positivists out there: in the intellectual space opened by proper analysis of drug studies, we need to grow a new and immeasurably complex science of mentality that makes sense of all the loose ends. And I mean "science," where the causal chain between a neuron and an action or emotion is defined precisely, with no gaps filled by an undefined (read: magical) "virtual machine."

The problem is that the vast majority of psychiatrists cannot conceive of mental disorder having a mental cause. To them, it's simple: "You're depressed means take antidepressants. See you in a month." What they need is:

1 - liberation from the simplistic notion that there can't be a science of mentality, and

2 - an understanding of how complex and far-reaching such a science will necessarily be.

The trouble is, in the war between a biological and a humanist psychiatry, philosophers have been useless. I give a lot more detail in the new book but there will be no progress until we can show a formal mental mechanism by which chronic anxiety can cause depression, such that alleviation of the anxiety resolves the depression (as in "I feel better already, just from knowing this wonderful tablet is going to cure me"). In order to turn this picture from pie in the sky to reality we need:

1 - an articulated mentalist (non-reductionist) theory of mind incorporating mental mechanisms sufficient to account for rational human behaviour, and ...

2 - a formal model of mental disorder based in plausible errors in just those mechanisms leading to disturbed human behaviour, aka mental disorder (and politics).

This model distinguishes very clearly between the actual mental mechanisms by which behaviour is computed, and the mental contents those mechanisms work on, i.e. the difference between a scientific psychiatry and an art of psychiatry. By 'mental mechanisms,' I don't mean Freudian ego mechanisms of defence, I mean something much more basic than these concepts which, while interesting and helpful, are purely descriptive. My proposals to satisfy these needs are set out in4; as an example of mental mechanisms we can turn to the next chapter in the search for a post-positivist psychiatry.

⁴McLaren N (2021): Natural Dualism and Mental Disorder: The biocognitive model for psychiatry. London, Routledge. (paperback and ebk).

Niall (Jock) McLaren is an Australian psychiatrist who recently retired after 50 years of practice. He has extensive experience in military, forensic and remote area psychiatry, all at the rough and unglamorous end of psychiatry. As a specialist, he went back to university to study philosophy and has published a number of monographs on the application of the philosophy of science to mental disorder, most recently brought together as the biocognitive model for psychiatry. This is based in the concept of natural dualism, and provides a working model for mental disorder as a primary psychological matter, with no reason to suspect brain pathology. He lives in the rural outskirts of Brisbane with his family and keeps busy growing trees.