Think by Simon Blackburn

Chapter 1c Knowledge Descartes is a

A. skeptic B. rationalist C. epiphenomenalist D. empiricist Rationalism vs. Empiricism

„ In the introduction we were introduced to the word “empirical,” which means “based on experience. „ These are the two classically opposing points of view in the study of knowledge:

‰ Rationalism: knowledge is based on reason.

‰ Empiricism: knowledge is based on experience. Hume’s Critique

„ About 80 years or so after Descartes died a Scottish philosopher named David Hume made a crushing critique of Descartes’ methodology. (p.40) „ Hume’s critique of Descartes method of doubt is essentially just that it is doomed to fail from the beginning. „ He claims that even if we find something like the self that is indubitable, we will never be able to advance past that, because we are still doubting all the basic principles of reasoning that we would need to do so. Rationalism vs. Empiricism again

„ Hume trusted reason, but he rejected rationalism.

„ For Hume, our knowledge of the world is dependent on experience. This makes him an empiricist. Descartes vs. Hume

„ Just about everyone agrees that both reason and experience are required for knowledge in an ordinary sense. „ Hume and Descartes understand this, too. Their debate is about the ultimate foundation of knowledge. ‰ Is the trustworthiness of experience ultimately based on reason? ‰ Or is the trustworthiness of reason ultimately based on experience? The difference between a rationalist and an empiricist is:

A. Rationalists believe in reason, but empiricists believe in experience. B. Rationalists believe that the foundation of knowledge is reason, but empiricists believe that the foundation of knowledge is experience. C. Rationalists believe in the Cartesian Circle, but empiricists reject the Cartesian Circle. D. Rationalists are foundationalists, but empiricists like Hume question the very possibility of a foundation for knowledge. Foundationalism

„ Hume and Descartes actually agreed that knowledge requires a foundation. They just disagreed on what sort of foundation could be supplied. ‰ Descartes believed that knowledge required an absolutely certain foundation, one that could not possibly be wrong. ‰ Hume believed absolute certainty about the world is impossible. For example, Hume thinks it is impossible to prove that the past is a guide to the future. Nevertheless, he thinks this assumption is what all empirical knowledge is based on. Hume argued that Descartes made a mistake in believing that:

A. our beliefs need a foundation. B. in believing that evil demons and such might exist. C. in requiring that the foundation of knowledge be beyond doubt . D. knowledge of the world can not be achieved. Webs

„ Blackburn points out (p.44) that some philosophers disagree with the whole foundationalist perspective. „ This is nicely captured by a famous quote from the early 20th century Austrian philosopher Otto Neurath:

‰ We are like sailors who on the open sea must reconstruct their ship but are never able to start afresh from the bottom. Neurath’s point

„ Neurath’s analogy captures Hume’s point that it’s really impossible to doubt everything at once. This would require getting out of the ship. „ But he takes Hume’s point further by observing that none of our beliefs are really foundational in the sense of being self- evident or self-justifying. „ Any belief we have can be questioned, just like any plank in a ship could be found rotten and in need of replacement. Coherentism

„ Philosophers who reject foundationalism are often called coherentists. „ Coherentists basically believe that knowledge is not a matter of our beliefs all resting on a firm foundation. „ Rather, knowledge is a matter of our beliefs fitting together or cohering in an optimum way, like the pieces of a jig saw puzzle. Problems with coherentism

„ But the jig saw analogy is troublesome, because, unlike a jig saw puzzle, we don’t have any assurance that there is one best way for our beliefs to fit together. „ If there are multiple way that our beliefs can fit together, but only one way that the world actually is, then its hard to see how coherentism can be right. Otto Neurath rejected

A. Rationalism B. Empiricism C. Foundationalism D. Coherentism Example

„ Blackburn gives you an example from the early 20th century British philosopher Bertrand Russell. (p.46). ‰ Russell asked: “How do I know that the world did not come into existence just a few moments ago complete with the delusive traces of a previous age?” „ This seems like an insane question, but it is a logical possibility. (In fact, what is really weird about this is that there are reasons for thinking it is likely.) The point

„ The point is that: ‰ Descartes’ evil demon world. ‰ Russell’s delusive memory world. ‰ Putnam’s brain-in-a-vat world. ‰ Our ordinary scientifically informed conception of the external physical world. „ are all equally coherent, but they can’t be all equally correct, since they clearly contradict each other. „ So, despite its appeal, coherentism is not a theory of knowledge that provides an answer to Descartes’ skeptical concerns. Conclusion

„ What both Descartes and Hume showed us is that if we take private experience as our starting point for a theory of knowledge, then we are probably doomed to skepticism. „ Most contemporary philosophers and scientists will point out that the one reason for beginning with private experience- that it can not be doubted- is not obviously correct. „ So it seems like it makes more sense to simply begin with the unprovable assumption that there is an external world, and go on to inquire into its actual nature. „ This is a hard enough task, as we’ll see in Chapter 7. Descartes’ one certainty, that he exists as a thinking thing, was ultimately

A. based on wishful thinking. B. not adequate to serve as a foundation for human knowledge. C. discovered to have been implanted by the evil demon. D. adopted by even his strongest critics.