Rene Descartes Archives



More Generally: Historical Thinkers (226)

September 27, 2013

Quote of the Day: Margaret Cavendish on Rational Animals

That all other animals, besides man, want reason, [Descartes] endeavours to prove in his discourse on method, where his chief argument is, that other animals cannot express their mind, thoughts or conceptions, either by speech or any other signs, as man can do: For, says he, it is not for want of organs belonging to the framing of words, as we may observe in parrots and 'pies, which are apt enough to express words they are taught, but understand nothing of them. My answer is, that one man expressing his mind by speech or words to another, doth not declare...
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May 17, 2012

A Brief History of Christian Conceptions of the 'Soul'

It is sometimes said that Christianity presupposes the existence of a soul, that, due to the progress of science, this view is no longer credible, and that, therefore, Christianity can no longer be taken seriously. It is very probable that there are some combinations of views, widely held among self-identified 'Christians', which can be effectively criticized along these lines. However, there are several puzzling features about this line of thought. The first is that it is not clear what the relevant 'progress of science' is supposed to be. Neuroscience is indeed advancing, but it can hardly be considered so advanced...
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October 12, 2011

Locke and Berkeley on Cartesian Skepticism

Descartes's First Meditation is one of the most striking texts in the history of philosophy. As anyone who has taught the text can attest, students are immediately gripped by the problem, and often despair of a way out. John Locke was evidently not such a student, for he responds to these doubts primarily with ridicule: If any one say, a Dream may do the same thing [as sense perception], and all these Ideas may be produced in us, without any external Objects, he may please to dream that I make him this Answer, 1. That 'tis no great matter, whether...
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May 26, 2011

True and Immutable Natures in Descartes's Ontological Argument

In the Fifth Meditation, Descartes argues that "from the fact that I cannot think of God except as existing, it follows that existence is inseparable from God, and hence that he really exists" (CSM 2:46). Caterus famously replied with the 'existing lion' objection (parallel to Gaunilo's 'Lost Island'): we can't think of anything as an existing lion without thinking of it as existing, so the existing lion must exist (CSM 2:72). In fact, Caterus didn't need to add 'existing' at all: existence is a necessary condition for the exemplification of any property whatsoever. Nothing can be red, blue, five feet...
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February 1, 2010

Philosophers' Carnival 103

The 103rd Philosophers' Carnival is now up at Philosophy, etc. with a link to my post on seeing the world through teleology-colored glasses. Also of interest in the new philosophers' carnival is Chris Hallquist's discussion of reformed epistemology and moral realism. In the course of his discussion, Chris gives a narrative of the history of early modern philosophy which is similar to my Berkeley-centric narrative (despite not mentioning Berkeley): Descartes sets up an impossible program, Hume shows that either Cartesian or classical empiricist assumptions lead inevitably to skepticism, and this motivates a 'Reidian' program...
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January 20, 2010

A Berkeley-Centric Narrative

Continuing the discussion of the historiography of modern philosophy, I want to consider an alternative narrative. The standard narrative is Kant-centric: the rationalists and empiricists spend a century squabbling, then Kant comes along and figures out what's right and what's wrong with each view, resulting in the Critical Philosophy. The key figures, apart from Kant, are Descartes, the great founder of the rationalists; Locke, the great founder of the empiricists; and Hume who called attention to the severe failings of both schools. (When I took intro to modern at Penn, this is exactly the way it went: these were the...
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January 12, 2010

Alternative Groupings of Early Modern Philosophers

Last month, there was some blog discussion about historiography and teaching methods in early modern philosophy. The standard story is evidently due to Hegel, and continues to be standard despite being unpopular among specialists in history of modern. It groups modern philosophers before Kant as follows:
Rationalists
Descartes
Spinoza
Leibniz
Empiricists
Locke
Berkeley
Hume
Dana McCourt, blogging at The Edge of the American West...
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September 18, 2009

Quote of the Day: A Source in Descartes for Berkeley's Visual Language Theory?

We must take care not to assume - as our philosophers [i.e. the scholastics] commonly do - that in order to have sensory awareness the soul must contemplate certain images [i.e. the species] transmitted by objects to the brain; or at any rate we must conceive the nature of these images in an entirely different manner from that of the philosophers. For since their conception of the images is confined to the requirement that they should resemble the objects they represent, the philosophers cannot possibly show us how the images can be formed by the objects, or how they can...
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January 23, 2009

How Putnam Defeats Descartes' Demon

A little while back, I wrote a post describing Cartesian demon skepticism as a form of 'adversarial epistemology'. The idea is that Descartes' thought experiment can be conceived of as a game with two players: the meditator and the demon. The meditator selects a process for forming beliefs from perceptual experiences, and the demon knows what process the meditator has selected, and controls all of the perceptual experiences. If the meditator ends up with mostly true beliefs, she wins. Otherwise, the demon wins. Now, I mentioned at the bottom of that post that this way of framing the problem is helpful...
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December 22, 2008

Cartesian Demon Skepticism as 'Adversarial Epistemology'

In one of my computer science classes in undergrad, we discussed a particular way of thinking about the efficiency of an algorithm, which the professor called 'adversarial upper bounds'. The idea was to suppose that someone knows the 'guts' of your algorithm - exactly how it works - and that person is trying to make your algorithm take as many steps to complete as possible. The upshot was that sometimes with this kind of system inserting some randomness will give you a better expectation value. For instance, suppose I am trying to find a route (just any route) from A...
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November 16, 2008

Three Varieties of Certainty

'Certainty,' whatever that is supposed to be, would certainly (!) seem to be important in epistemology. Like a lot of important words, it frequently gets thrown around without definition. I know of at least three totally distinct ways of using this term, and the only thing they all seem to have in common is 'very high epistemic status' - i.e. something is certain if we really know it, in some way that is 'better' (more certain!) than ordinary knowledge. I'm going to outline here these three different varieties of certainty. Cartesian Certainty (also called 'demon-proof certainty') is attributed to a...
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October 18, 2006

Descartes, Berkeley, and Moore on the Existence of the Spiritual and the Physical

I have been thinking recently about Moore's argument for the existence of the physical world.
For those who may not be familiar, Moore's argument looks something like this:
  1. Here is one hand; here is another
  2. If there are two hands here, then two hands exist.
  3. Hands are physical objects
  4. Therefore, physical objects exist
This simple argument seems to be part of the reason why many contemporary analytic philosophers do not consider idealism a live issue (something that I intend to make it my business to change). However, it seems to me to have two enormous and equally simple defects:
  1. It isn't actually an objection to Berkeley's theory, since Berkeley accepts all of the premises and the conclusion.
  2. Most people who make this argument are physicalists but if you accept the argument then, by parity of reasoning, you must allow Descartes to prove the existence of the soul.

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