Concluding Lecture for Hauptli’s Descartes: Sensible Doubts and Legitimate Knowledge?  

Copyright © 2018 Bruce W. Hauptli

For a contrast to Descartes’ a priori “first philosophy, we can look to an account offered by Penelope Maddy in her intentionally titled Second Philosophy: A Naturalistic Method.  Early in her account she says her inquirer is:

…entirely different from Descartes’ mediator.  This inquirer is born native to our contemporary scientific word-view; she practices the modern descendants of the methods found wanting by Descartes.  She begins from common sense, she trusts her perceptions, subject to correction, but her curiosity pushes her beyond these to careful and precise observation, to deliberate experimentation, to the formulation and stringent testing of hypotheses, to devising ever more comprehensive theories, all in the interest of learning more about what the world is like.  She rejects authority and tradition as evidence, she works to minimize prejudices and subjective factors that might skew her investigations.  Along the way, observing the forms of her most successful theories, she develops higher-level principles—like the maxim that physical phenomena should be explained in terms of forces acting on a line between two bodies, depending on the distance between them—and she puts these higher-level principles to the test, modifying them as need be, in light of further experience.  Likewise, she is always on alert to improve her methods of observation, of experimental design, of theory testing, and so on, undertaking to improve her method as she goes.[1] 

Whereas Descartes finds he must adopt his foundational first philosophy because the many falsehoods he had accepted since childhood had severely infected his whole body of knowledge Maddy’s

…inquirer will agree that many of her childhood beliefs were false, and that the judgements of common sense often need tempering or adjustment in the light of further investigation, but she will hardly see these as reasons to suspend her use of the very methods that allowed her to uncover those errors and make the required corrections.  It is hard to see why the [Cartesian] meditator feels differently. 

  The reason trace to Descartes’s aim of replacing Scholastic Aristotelianism with his own Mechanistic Corpuscularism.[2] 

Descartes’s meditator begins by rejecting science and common sense in the hope of founding them more firmly by philosophical means, our inquirer proceeds scientifically and attempts to answer even philosophical questions by appeal to its resources.  For Descartes’s meditator, philosophy comes first; for our inquirer, it cones second….[3] 

     Whereas the Cartesian meditator is motivated by what might be called “a quest to conquer an external skepticism”—one which places all of human knowledge and understanding in question, the contemporary second philosopher believes skepticism only arises from within our structure of knowledge (it is our perceptions, beliefs, theory, and principles) which raise skeptical concerns), and it is only by appeal to these that we can answer such questions (and improve our perceptions, beliefs, theories, and principles).  This view doesn’t try to overcome Cartesian skepticism, but instead argue that it is utterly mistaken. 

     Another difference between the Cartesian meditator and the second philosopher is that whereas the former adopts and a priori philosophical approach which limits him to deductive and certain beliefs, theories, and principles; the latter accepts that we are fallible and must rely on a posteriori perceptions, beliefs, theories and principle.  Instead of adhering to the metaphor of a builder reconstructing the storehouse of knowledge from an external perspective upon subjective principles which are to be absolutely certain via a deductive process which will yield a body of knowledge whose certainty is metaphysically-guaranteed, she adheres to the metaphor of a group of onboard shipwrights modify their conceptual structure while remaining onboard—as there is no independent point from which the revision process may be conducted (no metaphysical dry-dock), they must use the perceptions, beliefs, theories, and principles they have as they work to make their body of knowledge more sea-worthy.  They must be prepared to readily revise and question proposals for revision and must scrutinize proposed changes intersubjectively. 

     Clearly another important difference between the Cartesian meditator and the naturalistic second philosopher is that the former is committed to a transcendental supernaturalistic world view whereas the latter is committed to a naturalism which denies (or at a minimum refuses to rely upon—for metaphysical; epistemological, moral, or psychological purposes) that there are the supernatural grounds appealed to by the former thinkers. 

     Finally, another important difference between the Cartesian meditator and a naturalistic inquirer is well captured by Joseph Cottingham in his review of Roger Scruton’s On Human Nature as he discusses Scruton’s view that we are essentially persons and that

…we should understand the person as an ‘emergent entity, rooted in the human being but belonging to another order of explanation that that explored by biology.’  Ontologically, a person is not something over and above the life and behavior of the organism, but it is not reducible to them either.  And he deploys a familiar but suggestive analogy to explicate this, that of the relationship between a painting (of a face, for instance) and the blobs of ink on canvass that constitute it: ‘the person eludes biology in just the way that the face in the picture eludes the theory of pigments.  The person is not an addition to the biological: it emerges from it in something like he way the face emerges from the coloured patches on a canvas.’ 

  This irreducible personal dimension, as unfolded by Scruton, depends on the capacity for rational self-conscious thought that is unique to our kind.  We have a sense of ourselves as unique subjects of experience, looking out on the world from a horizon that no one else can cross, yet at the same time able to interact with other subjects, to offer them reasons for our actions, and reciprocally, to respond to the reasons they offer for theirs; and from this is derived the whole precious network of freedom and responsibility that structures and gives meaning to our human lives.’[4] 

Whereas Descartes wants to discuss wholly separate ontological entities (the infinite substance, as well as finite thinking things and finite extended things), the naturalist wants to discuss a single natural world which consists of many types of “things” (inanimate atoms, compounds, viruses, living things, persons, etc.) which can be arranged in terms of complexity.  Sometimes the characteristics of the complex things can be “reduced” to the characteristics of the less complex, but sometimes new characteristics emerge which are not so reducible.  Unlike Cartesian minds, bodies and body/minds, however the naturalist’s bodies and persons are not essentially metaphysically distinct and wholly separable things which might exist on their own independently from one another )and requiring some sort of “transcendental cause” for their interaction).  Instead, one can say, perceptions, emotions, beliefs, and moral actions, emerge from bodies and yield a “new order” which requires new sorts of explanations which are not needed if the emergence does not occur. 

     Here, of course, the real work for naturalistic philosophers, cognitive scientists, psychologists, sociologists and others becomes important, but that is another story. 

     From this sort of naturalistic viewpoint, however, the question posed in the Course Title, has a clear answer: Descartes’ doubts are not sensible, and his conception of our knowledge is illegitimate.  But the remedy is not to return to the Aristotelian Scholasticism which Descartes was concerned to reject.  Though there are adherents to Scholasticism today, as well as Platonists, Aristotelians, Augustinians, Thomists, Cartesians, Kantians, and many other adherents of prior philosophical schools, as well as Marxists, Hegelians, existentialists, and postmodernists; the conception of “second philosophy” slowly developed out of the successes, challenges, and failures which developed in the period from Descartes to contemporary philosophers.  It has by no means become the dominant contemporary philosophical viewpoint, but it does carry significant promise. 

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Email: hauptli@fiu.edu 

Last revised: 04/25/18.