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Saturday, November 29, 2014

Theories of Knowledge - Locke and Hume

"If you would be a real seeker after truth, you must at least once in your life doubt, as far as possible, all things."--René Descartes

Alice C. Linsley

Francis Bacon insisted that methodical observation and experimentation (the scientific method) can progressively increase human knowledge and benefit all of humanity. Bacon also demonstrated through his experiments that the senses can be fooled and thus raised doubt about "common sense" ideas. Bacon insisted that true knowledge must begin with doubt. He wrote, "If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts, he shall end in certainties." --Francis Bacon (1605) The Advancement of Learning, Book 1, v.8

Descartes felt it necessary to one reject entirely all beliefs about which there is the slightest doubt. He wanted to build a system of belief based on certainty. Descartes' point of certainty was his own rational existence:  "I am thinking, therefore I am existing." He wrote in Discourse on Method, "But I soon noticed that while I thus wished to think everything false, it was necessarily true that I who thought so was something. Since this truth, I think, therefore I am, was so firm and assured that all the most extravagant suppositions of the sceptics were unable to shake it, I judged that II could safely accept it as the first principle of the philosophy I was seeking." (Part Four on "Proofs of the Existence of God and of the Human Soul)

Descartes develops this as a proof for the existence of God. He continues, "After that I reflected upon the fact that I doubted, and that in consequence, my spirit was not wholly perfect, for I saw clearly that it was a greater perfection to know than to doubt. I decided to ascertain form what source I had learned to think of something more perfect than myself, and it appeared evident that it must have been from some nature which is in fact more perfect... I was not the only being in existence..., and it followed of necessity that there was someone else more perfect upon whom I depended and from whom I had acquired all that I possessed. For if I had been alone and independent of anything else, so that I had bestowed upon myself all that limited quantity of value which I shared with the perfect Being, I would have been able to get from myself, in the same way, all the surplus which I recognize as lacking in me, and so would have been myself infinite, eternal, immutable, omniscient, omnipotent, and, in sum, I would possess all the perfections that I could discover in God."

Here Descartes articulates a form of the argument from design. The reasoning goes like this:  I find imperfection in myself and I recognize it, which means that I have consciousness of something or someone more perfect than myself. That being so, I must have been designed by that greater Perfection. Descartes wrote: "The very principle which I took as a rule to start with, namely, that all those things which we conceived very clearly and very distinctly are true, is known to be true only because God exists and because he is a perfect Being, and because everything in us comes from him. From this it follows that our ideas or notions, being real things which come from God insofar as they are clear and distinct, cannot to that extent fail to be true."

Descartes contributed to the development of new theories of mind and consciousness. He defined thought "to include everything that is within us in such a way that we are immediately aware [conscii] of it. Thus all the operations of the will, the intellect, the imagination and the senses are thoughts."

John Locke (1632-1704)

The British empiricist John Locke believed that experience alone is the basis of all knowledge. He argued this against Descartes's position that the human mind holds innate ideas.

Locke contributed to the development of theories of consciousness. If a thought is something “within us" of which we are conscious, what is the nature of consciousness? Locke insists that the mind is empty at birth, a tabula rasa. All our ideas are shaped by experience; sensations, and reflections.

Locke wrote that "the little and almost insensible impressions on our tender infancies have very important and lasting consequences." He argued that the "associations of ideas" that one makes as a child are very important because they are the foundation of the self. He warned against letting "a foolish maid" convince a child that "goblins and sprites" are associated with the dark of night for "darkness shall ever afterwards bring with it those frightful ideas, and they shall be so joined, that he can no more bear the one than the other." Locke's theory of association influenced educational theory up to the nineteenth century. Educators warned parents not to allow their children to develop negative associations. 

David Hume (1711-1776)

The Scottish philosopher David Hume continues the empiricist trajectory, developing the consequences of Locke's thought. Hume held that in the search for truth, we cannot rely on the common-sense pronouncements, popular notions, or metaphysical speculation. Building on Locke's epistemology, Hume tried to describe how the mind works in acquiring what is called knowledge. He concluded that no theory of reality is possible; there can be no knowledge of anything beyond experience. He wrote, "If we take in our hands any volume; of divinity or school metaphysics, for instance; let us ask, does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion." (Enquiry Concerning Human Understanding)

In Hume's view, normal human reasoning is flawed and this raises radical doubt about all claims to know something. When we give the reasons for our beliefs about the world, we find that many of the offered explanations are contradictory. For example, one person asserts that something is true for them, but another denies that it is true in their experience. How can something be said to be true for one person and not for another? After exposing a series of contradictions within the human reasoning process, Hume reaches this conclusion: "The intense view of these manifold contradictions and imperfections in human reason has so wrought upon me, and heated my brain, that I am ready to reject all belief and reasoning, and can look upon no opinion even as more probable or likely than another." (Treatise of Human Nature)

To the epistemological conversation he adds an additional criterion: do not consent to any belief that is not found to be universally true. This is the ultimate test of truth: that it should be demonstrated mathematically as a universal truth or, following Sir Isaac Newton, as a universal physical law.

Hume conceived of philosophy as the inductive, experimental science of human nature. He sought to discover the causes of human belief. For Hume, this is the proper work of philosophy. Book I of the Treatise of Human Nature and all of the first Enquiry represent his attempts to do exactly this. He wrote, "my intention never was to penetrate into the nature of bodies, or explain the secret causes of their operations. For besides that this belongs not to my present purpose, I am afraid, that such an enterprize is beyond the reach of human understanding, and that we can never pretend to know body otherwise than by those external properties, which discover themselves to the senses." (Treatise of Human Nature, Sec. V)

Despite Hume's radical empiricism, he continued to value common sense, and apparently did not take his own skepticism, such as the problem of induction, to the extreme that others did after him. He recognized that the consequences of his radical skepticism clashed with common sense and his concern for enlightenment scholarship.  [Antony G Flew, A Dictionary of Philosophy, rev 2nd edn (New York: St Martin's Press, 1984), p 156].

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