The concerns of idealism and empiricism have been of continual concern in philosophy. Pre-Kantian thought had this collision at the highest point of controversy. Idealism holds the view that reality is composed in the consciousness of various agents. It finds its most radical postulation in the work of George Berkeley. Berkeley famously holds that view that nothing exists in the absence of perception – ‘to be is to be perceived’, as the maxim states. The reality of objects is assured by their projection onto or within the consciousness of different agents.
Idealism here is represented by Berkeley who is the foremost proponent of a pure idealism in the western philosophical tradition. Similarly, he is the only major immaterialist thinker in his era of Enlightenment philosophy. The role of the perceiver is the final referent in the equation. This is in line with the return to science and the re-appropriation of classical values that characterized the Enlightenment worldview. Empiricism is headed by John Locke, the emphasis here is thus not as much on the perceiver as it is on the perceived objects. Within both traditions of philosophic thought there is great emphasis on perception as the key determining process in the attainment of reality (or an accurate representation thereof).
When perception is the key to proper inquiry there are two main branches of problems that must be accounted for, illusion and delusion. Illusion is a problem or difficulty with the function of sensory input and delusion, being a problem with the perceiving mind. The opposition between a mental and perceptual problem doesn’t hold up as well in contemporary philosophic thought, however it seems necessary to include these models of thought for the purpose of explicating the idealist-empiricist debate circa 1700s. Another framing concern is the epistemological character of the entire dialogue. It is specifically a drive toward certainty that fueled much philosophic inquiry.
Illusions, in the sense that one’s perceptions imply contradictory things, have often fascinated philosophers from Plato through Descartes and even until today. In Berkeley’s work Three Dialogues between Hylas and Philonous, he discusses a number of perceptual discrepancies using Philonous as his mouthpiece. The problem is stated that if one puts a hot hand in water the temperature feels cooler and warmer if one places a cold hand in the same water (Berkeley 142-143).
This is done within the context of Berkeley’s idealist project which is to remove attributes from the object and describe things in terms of their existence in perception. He starts by mentioning the limits of the senses: they cannot infer from observation to causes and are bound to that which is immediately perceived (Berkeley 138). In this manner, he argues that since there is a discrepancy in the perception of the same object. The ‘temperature’ of the water must not be a uniformed attribute that exists within the water. Otherwise, the water must be at once hot and cold and this is rejected as an absurdity (Berkeley 143).
Hylas raises the objection that while the sensation may be in the perceiver, the quality that gives rise to it must be within the object. This is countered by stating that such a quality has no bearing as we know of it only by our intellect. That is, we have removed it from any sort of corporeality. He writes in his principles that ideas of one God and ideas of man are both subject to being ideas, they cannot exist “otherwise than in a perceiving mind” (Berkeley 74).
Locke’s approach to this particular problem is addressed in a different way in his Essays Concerning Human Understanding. While Berkeley describes the sensations of heat and cold as analogous to sweetness and bitterness or more generally pleasure and pain, Locke conceives the situation of temperature as analogous the properties of motion. Locke holds the view that heat and cold are actually a form of motion at a minute level (Locke 2.8.21).
This is, of course, a prototypical view for the modern scientific view of temperature where heat is represented by low-level vibration of particles. The faster the vibration the higher the temperature. With this model, what we feel in the bucket example is the deceleration of particles in the warm hand and the acceleration of particles in the cool hand. The differential temperatures see to average themselves out. This model is well in line with the contemporary palette, however, it fails to address Berkeley’s perspective which erases the concept of an inherent quality.
The problem of delusion is brought up, again in Berkeley’s Three Dialogues between Hylas and Philonous. Hylas posits, “What difference is there between real things and chimeras formed by the imagination . . . since they are all equally in the mind?” (Berkeley 197). The answer comes that “ideas formed by the imagination are faint and indistinct”(Berkeley 197). This may be a submerged reference to Descartes demand for ‘clear and distinct’ ideas as the foundation of analytic truths.
Locke discusses this in his Essays Concerning Human Understanding. He suggests that wit produces combinations of ideas while judgement separates them (Locke 2.11.2). He writes, “How much the imperfection of accurately discriminating ideas one from another lies, either in the dulness or faults of the organs of sense; or want of acuteness, exercise, or attention in the understanding” (Locke 2.11.2). Furthermore, he suggests that ideas must link up with things. Sensation is produced by the conformity of the object with the perceiver (4.4.4).
The distance between the two thinkers is thus that of their views of the fundamental role of perception. For Berkeley it may seem that Locke is being overly skeptical on the role of the perceiver. For in the thinking of Locke the mind is not the origin but the senses which shape the mind. For Locke, we are born tabula rasa, a blank slate to be impressed by our sensory input.
Our mind takes up the job of shaping sensation after that point. This is to say with Locke we are in an a posteriori epistemology whereas with Berkeley we are a priori. The problem for Berkeley could thus be characterized as finding the foundation of knowledge on the continually shifting horizon of sensation rather than the static, constant world of ideas. In a way this is analogous to the divergence between Heraclitus who wrote that “nothings stays fixed” and Parmenides who held that “Being is unchanging” (Wheelwright 70,90). The problem has come from a long history and different forms of this dispute will likely continue with eternal perpetuity.
Armstrong, David M.. “Introduction”. In Berkeley’s Philosophical Writings. Ed. David M.
Armstrong. New York: Collier Books, 1965. 7-34.
Berkeley, George. Berkeley’s Philosophical Writings. Ed. David M. Armstrong. New York:
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Locke, John. An Essay Concerning Humane Understanding, Volume I. Jan 2004. <http://www.gutenberg.org/files/10615/10615.txt>. May 21, 2007.
Locke, John. An Essay Concerning Humane Understanding, Volume II. Jan 2004. <http://www.gutenberg.org/files/10616/10616.txt>. May 21, 2007.
Wheelwright, Philip. The Presocratics. New York : The Odyssey Press. 1966.