By Juan Bernal
(A reading of Richard Rorty’s theses in his book, Philosophy and the Mirror of Nature, stimulated some of the thoughts contained in this remarks.)
A traditional approach to perceptual knowledge and associated distinctions misled philosophers in the western tradition for periods following Descartes. The distinction between internal (subjectivity) and external (objectivity) played a major role, as did that between the merely contingent and the necessary. In addition, there was the desire to grasp the noumenal (the purely object, thing-in-itself).
Assumptions: Knowledge is an assemblage of accurate representations; and in order to set knowledge on a firm foundation one must show knowledge to be analogous to the direct apprehension of an object. [Rorty: They held to the notion of the foundation of knowledge based on an analogy with the compulsion to believe when staring at an object.” (162, ‘Mirror’)]
First: Descartes’ meditation leading the ‘Cogito ergo sum’ brings in the stark divide between the internal-mental realm (subjectivity) and the external-material realm (objectivity). With this comes the problem of establishing knowledge of the external on the firm foundation of ‘clear and distinct ideas’ clearly and immediately presented to the knowing subject. The knowing subject is a thinking being, a mind seeking to make sense of ideas presented to it, ideas which must represent objects in the material-physical realm.
Secondly: John Locke and other classical British Empiricists (Berkeley, Hume) accept a large part of the epistemological problem gotten from Descartes. They see their task as being that of showing how the subject can have knowledge of the external world. They focus on the mental processes underlying knowledge and beliefs about the external world; and on the subject’s apprehension of ideas or experience of impressions (putatively caused by external objects impinging on the senses).
Hence, they work with a notion of knowledge as primarily perceptual experience. In their ‘analyses,’ they tend to confuse explanation and justification, so that one is often unsure as to whether they’re doing a quasi-psychological explanation of mental processes that base our knowing something or trying to defend a form of propositional knowledge. But mostly they ignore propositional knowledge, i.e., they favoring ‘knowing of X’ (knowledge by direct acquaintance) over ‘knowing that P’ something is the case.
The divide between the subject’s experience and external reality remains evident; hence, the skeptical problem remains prominent.
Thirdly, Immanuel Kant moves part of the way to recognizing the propositional character of knowledge with his focus on the rules that the mind must apply in order to know anything. He recognizes that knowledge cannot simply be identified with perceptual experience, as the empiricists were inclined to do; but his focus on the structures of the understanding (mind?) indicates that he does not escape from of the idea that an explanation of knowledge requires some type of quasi-psychological analysis of mental processes. (However, Kant appears not to have discarded entirely the Cartesian distinction between the internal-mental-realm and the external-material-realm.).
Accordingly, what we experience (and can know) results for the synthesizing activity of the transcendental ego. But this, in turn, leads to a differentiation between objects of experience (phenomena) and the thing-in-itself (noumena). Human experience and knowledge are limited to phenomena.
On pages 160-161 of his book (Mirror..), Rorty tells us that Kant was the first to think of the foundations of knowledge as propositional rather than objects (i.e., ideas, impressions, sensations). Instead of a search for ‘privileged representations,’ Kant searches for the rules of the mind that make experience possible. Thereby, he advances in the direction of a propositional rather than a perceptual view of knowledge. But he only went half-way, because his ‘Critique’ was contained within the framework of causal metaphors —- “constitution,” “the working,” “shaping,” “synthesizing.”
[See Rorty’s summary statements of his assessment of the epistemological enterprise, Philosophy and the Mirror of Nature, pages 160-163. See also he work on Kant by Robert Paul Wolff, Kant’s Theory of Mental Activity) ]
Epistemology and the problem of Justifying our Knowledge
The “Cartesian Problem”: The subject (the thinking being = mind) apprehends ideas. The basis for any knowledge outside the subject’s state of consciousness is the apprehension of clear and distinct ideas, because these are the only basis for the certainty required by knowledge. So the problem of showing how knowledge of external (material) reality is possible is the problem of showing how the subject’s apprehension of clear and distinct ideas bridges the gap between subjective consciousness and external (material) reality. This is often called the “skeptical problem”:
The problem: How do we get from A to B?
A: The subject apprehending his immediate impressions, perceptions, sense-data, etc , i.e. Subjective Experience.
B : Knowledge of objective (material) reality
John Locke, Bishop Berkeley, and David Hume in turn take up this problem, with Hume showing that it leads to a philosophy of skepticism regarding both the reality of an enduring self and knowledge of objective reality.
John Locke (primary/secondary qualities) -> Berkeley’s Idealism –> Hume’s Skepticism
In turn the challenge of David Hume’s skepticism was the subject of Immanuel Kant’s critical philosophy (of the Critique of Pure Reason).
(Kant’s Critical philosophy) purports to resolve (Hume’s Skeptical philosophy).
Kant argued that there were three responses to the Cartesian problem:
Humean Skepticism (an untenable position)
Dogmatism (Naïve Realism [e.g., Thomas Reid’s Realism?])
Kant’s Critical Philosophy (Transcendental Synthesis of experience).
Only the latter was thought to constitute an adequate, philosophical resolution of the Cartesian problem.
Acordingly, skepticism develops from the empiricism of Locke and Berkeley. Dogmatism or naïve realism simply ignores the divide between subject and objective reality and posits that the subject directly apprehends objective things and properties. In the Kantian approach, the subject contributes the forms of intuition and categories of the understanding to make experience and knowledge possible. The Kantian ‘solution’ is presumably one satisfactory response to the Cartesian challenge.
The challenge of the Cartesian problem is handled by Immanuel Kant’s critical philosophy (of the Critique of Pure Reason), satisfactorily in the opinion of many, but not all agree. The crucial point is that Kant accepts the Cartesian problem as the starting point and then argues that his critical philosophy shows how experience and knowledge of objective reality are possible.
But there are alternative ways of dealing with the problem, such as representative realism and phenomenalism. I will not discuss these, but instead will mention an alternative model of perceptual experience which avoids the skeptical problem altogether and, contrary to the accepted view, is not a piece of mere dogmatism. The common-sense realism of Thomas Reid, can be developed into a Darwinist-Pragmatist model of sense perception.
Thomas Reid, a Scottish philosopher and contemporary to David Hume, rejected the Cartesian starting point, opting for a common sense premise that humans know and interact with a material world. Reid’s common-sense realism [An Inquiry into the human mind (1764) & Essays on the Intellectual Powers of Man (1786)] has the character of dogmatism only when viewed from a perspective of the Cartesian problem. When that starting point is rejected, Reid’s philosophy has the advantage of avoiding the idea of perception as passive sensing in favor of a propositional account of perception. This has much to recommend it. Furthermore, this type of realism can be seen as reinvigorated, first by the Darwinian evolutionary account of animal life, including the evolution of intelligent, mindful humans, competing for survival in the world; and secondly by a scientific based pragmatism, of the sort developed by John Dewey.
Here we have an alternative to the Kantian ‘resolution’ of the Hume’s skepticism. Kant’s resolution accepts the Cartesian problem and offers the transcendental philosophy of the first Critique as a solution to that problem and all its offspring.
The alternative solution (Reid, Darwin, Dewey) starts by rejecting the Cartesian problem and, along with it, all the offspring (including Humean skepticism). In its place we have the common-sense realism of Thomas Reid, which can easily be seen as harmonious with a Darwinian Evolutionary philosophy and with a modern pragmatic philosophy, such as that developed by John Dewey.
With the model of sense perception of sense perception, which I shall call the “Reid-Darwin-Pragmatic model,” we assume as a starting point the existence of the individual in a natural, social world. Instead of saying with Descartes that there is a chasm between the perceiver (the subject) and the objective, physical world which must be bridged if we’re to avoid the skeptical trap, we assume that the subject occupies a place in that objective, material world, which he perceives and with which he causally interacts. In other words, we start with a picture of the person (human being) located in a natural/social world, perceiving things (not apprehending perceptions), interacting with other persons and participating in actions and events, all of which also are found in that world. He does not just perceive things, but also causally interacts with many parts of the world which he inhabits.
Not only do we avoid the skeptical dilemma, but this model also avoids the serious conceptual problems of the Cartesian-Humean mode, some of which include: .
First, the subject of the Cartesian-Humean model has to be an abstract ego, a mental subject or “homunculus” existing inside the head who apprehends the data (perceptions, impressions, sense datum) provided by the sense faculties. The perceiving subject is not the physical person who walks the earth, but a mysterious “ghost-in-the-machine” receiving sense impressions.
Secondly, the Cartesian-Humean model assimilates the act of perception to a passive sensing or reception of sensation. This ignores the fact that an adequate analysis of perception reveals that the act of perceiving presupposes that the perceiver applies relevant meaning and concepts to the object perceived. In other words, perception is concept-laden, propositional in nature, an activity, and cannot be adequately analyzed as a passive sensing of immediately given data.
Thirdly, we avoid the problem of presented by a subjective, private language, whose concepts presumably do not rely on concepts applied to the external world. Ludwig Wittgenstein and ordinary language analysts have fairly refuted the notion of a private language. But the model of a subjective ego apprehending and identifying private impressions assumes the applicability of a private language, which ultimately turns out to be an incoherent notion.