Sunday, February 27, 2022

Scientific realism versus instrumentalism

 


“A philosopher who is not trained in a scientific discipline and who fails to keep his scientific interests alive will inevitably bungle and stumble and mistake uncritical rough drafts for definitive knowledge.  Unless an idea is submitted to the coldly dispassionate test of scientific inquiry, it is rapidly consumed in the fire of emotions and passions, or else it withers into a dry and narrow fanaticism” 

Karl Jaspers

Way to Wisdom, p. 159

 

I encountered 2 philosophical ideas today that I did not have any disagreement with and decided I would take that as a sign and discuss them here on my blog. Readers may have noticed that I am very skeptical about what philosophy adds to psychiatry and have posted numerous examples over the years. Today the above quote was posted on Twitter and it is an idea that I completely agree with. One of the problems that I have with philosophy in psychiatry is that is generally written as a rhetorical attack on the field. That is easy to do when you control the premise and that premise is generally false. There are numerous examples but the most obvious one is defining what you consider a disease to be and then concluding that no mental illnesses are diseases. More specific examples are available such as using similar definitions for addiction and then concluding that addiction is not a disease. Many of the people posting these arguments are not scientists or clinicians but in some cases are clinicians who have yet to have ever seen the patient they are talking about or who have never seen a patient – period.  To a large extent I think this is what Jaspers is focused on in this quote. It comes from a chapter in the reference book that is labeled as “Appendix 1: Philosophy and Science” and states that it was reprinted by permission from the Partisan Review.

The second opinion piece was from Kenneth Kendler, MD a leading expert in psychiatry, genetics and psychiatric research. He also has written extensively on the evolution of psychiatric thought over the decades and how philosophy applies to psychiatry. I have probably read at least a hundred papers written by Dr. Kendler in the past 30 years – and that is a small number of the papers he has written. I have also read his book Why Does Psychiatry Need Philosophy wherein he and his co-authors are focused on issues of phenomenology, nosology, and the degree of explanation as the subtitle suggests.

In the opinion piece (3), he takes a brief look at the philosophy of science and how that applies to the DSM.  He describes the main philosophical divisions as scientific realism and instrumentalism as they apply to diagnoses.  With scientific realism whatever the diagnostic construct - it is accepted at face value.  They are thought to really exist that way. The best examples I can think of from the DSM are Dissociative Identity Disorder and Intermittent Explosive Disorder.  Both are highly problematic and yet – there they are in the DSM. Further - the people who believe they exist seem undeterred in their use and they seem to be just carried along with subsequent revisions of the DSM.  Instrumentalism on the other hand sees diagnostic constructs as a work in progress.  They are not accepted as ultimate diagnoses but are subject to the scientific process of validation by empirical evidence. A good example in that case would be schizophrenia subtypes.  Previous editions of the DSM had 5 subtypes of schizophrenia including paranoid, catatonic, disorganized, residual, and undifferentiated.  Psychiatrists treating acute schizophrenia noticed that the subtypes were not consistent over time and the same person could be diagnosed with different subtypes. On that basis, the DSM-5 revision dropped the subtype classification but unfortunately implemented a schizophrenia spectrum of disorders.  I think that applying a physical concept to heterogeneous group of biologically determined disorders is probably a step in the wrong direction and that an instrumentalist approach will eliminate spectrums in the future along with Dissociative Identity Disorder and Intermittent Explosive Disorder

Kendler goes on the discuss 5 arguments in favor of an instrumentalist approach.  Before I raise those points, why would everyone not be in favor of this approach? Certainly, math and science majors would. Even though you can specialize in physical and biological science before medical school and students at that level don’t get much explicit instruction in the history of science – it happens nonetheless. Most high school students in the US are exposed to Darwin, Lamarck, and the DNA double helix as sophomores in high school. Almost all of the main concepts in physics and chemistry include some discussion of innovation and how earlier theories were rejected. That approach is more notable in medical school where some of the timelines and necessary technology become clearer. All of that information greatly favors an instrumentalism over scientific realism.  Although psychiatry is a relatively new discipline, it is clear that diagnostic systems have been greatly modified over the past 100 years from the Unitary Psychosis model o the 19th century.

His first argument - pessimistic induction highlights the history of changes in diagnoses in the past and suggests that we should expect the same pattern in the future. A counterargument is that significant refinement has occurred and we can expect fewer errors than in the past but at any rate these observations need to be made.  The second argument is that given the nature of descriptive diagnoses rather than direct test observation determining validity will always require an instrumentalist approach.  The third argument is that the uncertainty about two competing diagnoses can be empirical or conceptual. Kendler favors the latter and that means changing the construct. The fourth argument is that scientific advances in psychiatry cannot be predicted or anticipated and are potentially transformative.  An empirical approach is required to test the future approaches against the current approaches and make the indicated modifications.  The fifth argument reduces a reverence bias toward existing diagnoses, much like clinicians use the provisional diagnosis term to reflect diagnostic uncertainty. 

He touched on the problem of how polygenic heterogeneous disorders can lead to the philosophical problem of multiple realizability.  That is - multiple genotypes leading to the same phenotype and the implications that has for moving to a diagnostic system that includes etiology. He points out that psychiatric disorders have higher degrees of polygenicity.  He briefly alludes to the potential problem of scientists with epistemic privilege studying nosology and phenomenology – but concludes on a more positive note about current research methods not available to previous generations.

Al things considered this did not seem like a powerful argument for philosophy in psychiatry. The current arguments in favor of instrumentalism seem like the general process of science.  The exceptions mentioned for psychiatry did not seem that specific relative to other specialties diagnosing complex polygenic disorders. I really wonder who the psychiatrists are who accept DSM diagnoses at face value?  I don’t think that I have ever met one.

That leads to the question of whether there are philosophical approaches that might be useful to psychiatry.  In my research for this post – I did find a fairly interesting one called constructive empiricism by von Fraassen (7,8).  Simply defined constructive empiricism states:  “Science aims to give us theories which are empirically adequate; and acceptance of a theory involves as belief only that it is empirically adequate.”  This is a departure from scientific realism and the premise that science is giving us the truth and belief in the theory means believing it is true. There is debate regarding the empirical adequacy of a theory with the critics using circularity arguments and the defenders pointing out that it is determined by scientists for specific goals. Philosophical debates tend to be endless and there are seldom any clear answers.  To me constructive empiricism seems to be an accurate description of what happens in psychiatry both at the biological and phenomenological levels. It certainly applies to the diagnoses of schizophrenia spectrum as opposed to subtypes and Dissociative Identity Disorder used in the original paper and many other papers written by Kendler on the evolution of various diagnoses over time. 

The critics of psychiatry are another story. There are people in the world right now who attack the entire diagnostic system of psychiatry. They either don’t have alternatives or the suggested alternatives have not been widely validated or adopted. In some cases, the theoretical basis for their proposed system is highly questionable. These same critics always seen to caricature the diagnostic process as one that is based on neither scientific realism or instrumentalism. The best example I can think of is any paper written that characterizes the DSM as the Bible of psychiatry.  That speaks not only to a general level of ignorance about how it is regarded in the field but also the philosophical bias suggesting the approach to the DSM has been static and not based in reality - even though major disorders have been present for centuries.  The critics also have an associated lack of knowledge about the biological constraints – even as they are briefly outlined in this opinion piece.

These critics whether they are antipsychiatrists or not seem to believe that what is in the DSM is accepted as the truth based on blind belief by psychiatrists and there is no evidence that is true now or at any point in time.  The observable changing diagnostic criteria over time and teaching future generations about all of the constraints is the best way to address empirical adequacy.

         

George Dawson, MD, DFAPA

 

References:

1:  Jaspers K.  Way To Wisdom. Yale University Press, New Haven, 1951: p. 151.

2:  Kendler KS.  Why does psychiatry need philosophy? In: Kendler KS, Parnas J, eds.  Philosophical Issues In Psychiatry: Explanation, Phenomenology, Nosology. Baltimore, MD; The Johns Hopkins University Press, 2008: 1-16.

3:  Kendler KS. Potential Lessons for DSM From Contemporary Philosophy of Science. JAMA Psychiatry. 2022 Feb 1;79(2):99-100. doi: 10.1001/jamapsychiatry.2021.3559. PMID: 34878514.

4:  Chakravartty, Anjan, "Scientific Realism", The Stanford Encyclopedia of Philosophy (Summer 2017 Edition), Edward N. Zalta (ed.), https://plato.stanford.edu/archives/sum2017/entries/scientific-realism

5:  Eronen MI. Psychopathology and Truth: A Defense of Realism. J Med Philos. 2019 Jul 29;44(4):507-520. doi: 10.1093/jmp/jhz009. PMID: 31356663.

6:  Kendler KS. Toward a limited realism for psychiatric nosology based on the coherence theory of truth. Psychol Med. 2015 Apr;45(6):1115-8. doi: 10.1017/S0033291714002177. Epub 2014 Sep 2. PMID: 25181016.

7:  Monton, Bradley and Chad Mohler, Constructive Empiricism. The Stanford Encyclopedia of Philosophy (Summer 2021 Edition), Edward N. Zalta (ed.), https://plato.stanford.edu/archives/sum2021/entries/constructive-empiricism.

8:  von Fraassen, Bas. Constructive Empiricism Now. Philosophical Studies, 2001; 106: 151–170https://www.princeton.edu/~fraassen/abstract/docs-publd/CE_Now.pdf

Concept Credit:  Dr. Ahmed Samei Huda a colleague from the UK came up with the concept that the critics of psychiatry are functioning at the level of scientific realism when psychiatrists are not.  That occurred during a Twitter discussion. 


Supplementary 1:  In the philosophy world there are much more detailed and varying definitions of scientific realism (4) than what Kendler discusses in the opinion piece.  The most accessible article I could find on the subject is by Eronen (5) that is more or less a refutation of Kendler and Zachar’s position on scientific realism. I say more or less because the author takes various positions to illustrate that scientific realism is necessary or at the minimum his Kendler and Zachar’s position on scientific realism may be closer to his that not. What I like about the Eronen paper is that he uses very clear examples with clear diagnoses like anorexia nervosa to make his point. My longstanding arguments about the validity of major psychiatric diagnoses is that they have always been there and more than anything that has driven the need for psychiatry and psychiatric care.


Graphics Credit:

Karl Jaspers downloaded from WikiMedia Commons on 2/27/2022 per the following:

Universit├Ątsbibliothek Heidelberg, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons  at the following URL: https://commons.wikimedia.org/wiki/File:Karl_Jaspers_(HeidICON_33479).jpg


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