It seems strange that Cartesian mind/body duality is so widely accepted, given that it leads to scepticism around the possibility of human knowledge.

Why is it so widely accepted, and how do its adherents escape its seemingly inevitable scepticism (or come to terms with it)?

Please support any answer with cited references to reputable sources.

  • This link on Spinoza's epistemology might be useful to others: shodhganga.inflibnet.ac.in/bitstream/10603/14957/7/…
    – J D
    Aug 4, 2020 at 17:30
  • As for being active on SEP and having doubts about my propositions, I cite the following list that interferes with ascertainment of certainty: illusion, hallucination, memory, fallacy, bias, and deception, including self-deception. I have erred, I do err, and I will continue to err. Therefore, statements of fact are open to debate and certainty. I once believed in the Luther's god, and now I see 'god' is a linguistic device that doesn't represent some sort of omnipotent being is a psychological construct with an emotional purpose...
    – J D
    Aug 4, 2020 at 18:35
  • Hence according to my experience and understanding, 'true believers' are a manifestation of a psychological phenomenon where adequate doubt to build an empirically valid representation is deficient. Some psychologists go so far to consider a certainty of knowledge a psychological syndrome, though in the spirit of R. D. Laing, I am skeptical of such normative 'diagnoses'.
    – J D
    Aug 4, 2020 at 18:38
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    Widely accepted by whom? Analytic philosophers prefer physicalism and theists deny that it leads to skepticism. If you mean "the folk" they "accept" it mostly as a good enough stub for everyday transactions and skepticism is dismissed out of hand in that context.
    – Conifold
    Aug 4, 2020 at 20:42
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    It seems to me you confuse the epistemological position of external realism with the metaphysical position of dualism. For some 50 years now, the former is prevalent while the latter is rarely held. Metaphysical positions in general are mostly a derivative of what really is an epistemological position these days IMHO. Many philosophers refuse metaphysics as such as being nonsensical. Btw both internal and external realism are inconsistent.
    – Philip Klöcking
    Aug 5, 2020 at 17:04

1 Answer 1


In order to answer this question, it is important to explain the purpose and reasoning behind it. In the proposition below Spinoza announced, in his 'Ethics' Part 2- on the Origin and Nature of the Mind, his entirely revolutionary recognition of the presence and operating principles of the human mind and equally important of its union with and dependence on its body for knowledge concerning the sensible world. In other words, he resolved the mind/body problem. Unfortunately, a series of events ensued which kept this discovery from reaching any audience which could appreciate its importance for science and epistemology in general. Spinoza's work was banned shortly after his death primarily because he wrote a book called, the 'Theological/Political Treatise' in which he pilloried established religion including all of christianity and islam as being riddled with superstitious cant, built-in to the scriptures so as to control the masses and to manipulate their lives. It took over 150 years for the misunderstandings of Spinoza's system to come clear and it is only recently that the true merit of his scientific, ontological, epistemological and ethical contributions are slowly coming to light. While Spinoza was outcast, the capability as scientist, mathematician and metaphysician of Descartes came to the fore and his system came to be regarded as the foremost and leading theories about human nature and humans place and connection with the external environment.

Once Descartes split the world from the human perspective into two spheres, essentially mind (soul or spirit) and extended substance (body) this cleared the way for an unbounded movement towards a mechanistic world view which has permeated philosophy and essentially continues to do so today. He viewed 'matter' as inert substance, which required an external force to account for any physical change and removed any dynamic or causal element to the sensible world. By making matter inert, he voided the possibility about and certain knowledge about the 'world. The 'idealists' came along and removed and possibility of a 'knower'. Taken together, materialism and idealism obliterate any possibility of garnering any verifiable knowledge about the world. Today, philosophy appears to be attempting to work its way out of this corner which these two overriding systems painted it into. This world view now permeates so much of philosophical theoretic frames that it is not clear that if anywhere, the mechanistic/duality is even considered to have any other alternative as a 'given' as a basis for scientific theory.

And so the purpose of this question and now this answer is to introduce the notion that Spinoza positing of a human mind united with its body and acting as a 'potent agency' in the accumulation of certain knowledge stands as a viable alternative to the contemporary philosophical systems currently on offer.

Spinoza's more detailed and easier to understand exposition of this can be found in his TIE (Tractatus Emendatione Intellectus) Prop. XXI. "This idea of the mind is united to the mind in the same way as the mind is united to the body. Proof.—That the mind is united to the body we have shown from the fact, that the body is the object of the mind; and so for the same reason the idea of the mind must be united with its object, that is, with the mind in the same manner as the mind is united to the body."

Statement from Antonio Damasio, author of 'Looking for Spinoza': "According to Descartes' famous dualist theory, human beings were composed of physical bodies and immaterial minds. Spinoza disagreed. In "The Ethics," his masterwork, published after his death in 1677, he argued that body and mind are not two separate entities but one continuous substance." "Science is proving Spinoza more current," Dr. Damasio said over tea at his hotel during a recent visit to New York. "He intuited the basic mechanism of the emotions."

Brief capsule of Descartian dualism: ..."when Descartes, in the first half of the seventeenth century, said that there are only two kinds of things or substances in nature, namely, extended substances and thinking substances, or bodies and spirits; that, in bodies, everything is reducible to extension with its modifications of form, divisibility, rest and motion, while in the soul everything is reducible to thinking with its various modes of pleasure, pain, affirmation, reasoning, will, etc...; when he in fact reduced all nature to a vast mechanism, outside of which there is nothing but the soul which manifests to itself its existence and its independence through the consciousness of its thinking, he brought about the most important revolution in modern philosophy. To understand its significance however an account must be given of the philosophical standpoint of the time."

The point of view expressed here is not anti-anything, but rather pro-philosophy. It is not denigrating the scientific process, which results speak for themselves. It is not the work of science that is being called into question, it is what is theorized about the scientific platform or paradigm. Thanks to everyone who took the time to comment. All the Best, CMS

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    This answer does still not justify the faulty assumptions of the question. Philosophy has moved beyond Spinoza for quite some time now, beginning in the ~1880s (Dilthey's historicised a priori) and broadly accepted since the ~1960s (pragmatist life-worlds and the hermeneutical circle as limits of expressivity through language) IMHO. This does not belittle the indeed remarkable work of Spinoza, who was way ahead of his time (Jacobi and Mendelssohn argued about this as early as the 1780s!), but the whole notion of certain, eternal knowledge is really getting nowhere these days.
    – Philip Klöcking
    Aug 6, 2020 at 17:48
  • Your view doesn't denigrate science. In fact, the rejection of Cartesian duality tends to be a popular view of materialists following Ryle's work.
    – J D
    Aug 6, 2020 at 19:57
  • @Philip Hocking- Why you would accept someone else's rejection of Spinoza is beyond me. Try a careful reading, without imposing presuppositions or contemporary defintions, of "On the Improvement of the Understanding" and then let me know your impressions. Meanwhile, to gain some insight into why Spinozan commentaries are misleading, please see my, 'Footnote Fixation', on my Academia.edu website. Cheers,
    – user37981
    Aug 6, 2020 at 22:20
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    It's not like I hadn't been where you are. I've had this after extensive study of Kant. And late Husserl. And Wittgenstein. And Spinoza. And Sellars. And Putnam. The feeling that they, finally, gave me the profound truth I was searching for. But I went further, deeper, and realised that at the bottom of it, even the language allegedly denoting this truth is plastic, arbitrary, subject to change and that no single expression of any kind of truth is eternal. The later the authors, the more explicit this self-reflection. And then I read Plessner. And there, it is even part of the principles.
    – Philip Klöcking
    Aug 7, 2020 at 6:38
  • @Philip Hocking- and so, it took a sociologist to shake you from your philosophic slumbers, bully for you. And now, if I hurry, I can bask in the sunshine of your wisdom, mend the error of my ways and, dare I hope for it, become exactly like you. What a distinct honor awaits me. JUST JOKING! Cheers, Charles
    – user37981
    Aug 8, 2020 at 14:32

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