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Al-Ghazali on Skepticism

I'm currently reading Al-Ghazali's spiritual/philosophical autobiography for the first time. The translation I found in the library gives the title as Freedom and Fulfillment, but the book is better known in English as Deliverance From Error. I'm sure this has been noticed before, but the discussion of skepticism near the beginning of the book can be interestingly compared with some of the well-known discussions of skepticism in European philosophy. Here's a quick outline. Al-Ghazali states that he is looking for a kind of "certain knowledge" that will guarantee "safety from error" (§8). He recognizes that "the dicta of authority" (i.e.,...
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Philosophy and Trust in the Senses, from Montaigne to Berkeley

I want to begin this post with a longer sequence of quotations than is usual. The reason is that simply juxtaposing the quotations goes a long way toward telling the story I want to tell. Here, then, is a sequence of comments on philosophy and trust in the senses, ranging in date from 1580 to 1713: We want to find out by reason whether fire is hot, whether snow is white, whether anything within our knowledge is hard or soft. There are ancient stories of the replies made to the man who doubted whether heat exists—they told him to jump...
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"Berkeley on Unperceived Objects and the Publicity of Language"

Completing my summer research goals (only slightly late!), I've posted another new draft to my writings page, "Berkeley on Unperceived Objects and the Publicity of Language". The paper argues that when Berkeley's language of nature theory is interpreted in light of his own philosophy of language it produces a solution to the notorious problem of the existence of objects presently unperceived by humans.
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"How Berkeley's Gardener Knows his Cherry Tree"

I have posted a new draft, "How Berkeley's Gardener Knows his Cherry Tree" to my writings page. As always, comments and criticisms are welcome.
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Quote of the Day: Bayle on the Skeptical Consequences of Multi-Location

[If multi-location is possible] it follows that neither you nor I can be certain whether we are distinct from other men, or whether we are at this moment in the seraglio of Constantinople, in Canada, in Japan, and in every city of the world, under different conditions in each place. Since God does nothing in vain, would he create many men when one, created in various places and possessing different qualities according to the places, would suffice?

- Pierre Bayle, Historical and Critical Dictionary (1697), tr. Popkin, s.v. "Pyrrho," note B

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Berkeley's Second-Order Anti-Skepticism

Consider the following parallel passages from Berkeley's Principles and Dialogues: so long as men thought that real things subsisted without the mind, and that their knowledge was only so far forth real as it was conformable to real things, it follows, they could not be certain that they had any real knowledge at all. For how can it be known that the things which are perceived, are conformable to those which are not perceived or exist without the mind? (PHK sect. 86) It is your opinion, the ideas we perceive by our senses are not real things but images or...
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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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Berkeley and Sergeant

John Sergeant was a late seventeenth century English proponent of Roman Catholicism and Aristotelian philosophy. He is now mostly forgotten, though he is occasionally mentioned as a critic of Locke, partially because Locke and Stillingfleet discuss Sergeant's criticisms of Locke in their famous dispute. (Stillingfleet disowns Sergeant's criticisms; Stillingfleet and Sergeant had earlier been embroiled in a theological dispute about the rule of faith.) I mentioned a while ago that I think the Locke-Stillingfleet debate was an important influence on Berkeley. It looks like Sergeant may have been an important influence as well. First, in section 12 of the preface...
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Quotes of the Day: Berkeley and Hume on Unconvincing Arguments

But that all his [Berkeley's] arguments, though otherwise intended, are, in reality, merely sceptical, appears from this, that they admit no answer and produce no conviction. Their only effect is to cause that momentary amazement and irresolution and confusion, which is the result of scepticism. (David Hume, An Enquiry Concerning Human Understanding (1748): sect. 12.1.15) I am not to be persuaded by metaphysical arguments [for the existence of God] ... as they are not suited to my way of thinking they may perhaps puzzle but never will convince me. (Alciphron, the free-thinker, in Berkeley 1732 work by that name, sect....
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Gupta and Idealism: My Project for the Next Two Weeks

It's been a while since I posted anything, and even longer since I posted anything other than Aristotle quotes - I have been busy trying to get my term papers underway. Since I don't expect to have any more time in the near future than I have had in the recent past, I thought I would keep things going around here by posting an outline of one of my projects. Below is a very rough draft of an introduction to one of my two papers (it doesn't have a working title yet) which describes what I hope to accomplish. Comments...
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External Coherence and the Reality of The Matrix

David Chalmers writes: I think that even if I am in a matrix [i.e. any computer simulation similar to the one depicted in The Matrix], my world is perfectly real. A brain in a vat is not massively deluded (at least if it has always been in a vat) ... Philosophers have held this sort of view before. The 18th-century Irish philosopher George Berkeley held, in effect, that appearance is reality ... If this is right, then the world perceived by envatted beings is perfectly real: they have all the right appearances and appearance is reality ("The Matrix as Metaphysics"...
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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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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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The Reason for Berkeley's Anti-Abstractionism

In my post, Does Philosophy 'Trickle Down', I noted that "Berkeley thinks he has discovered two philosophical doctrines which are indeed 'the Chief Causes of Error and Difficulty in the Sciences' and also 'the Grounds of Scepticism, Atheism, and Irreligion.' These are the epistemic/linguistic doctrine of abstraction, and the metaphysical doctrine of corporeal substance." In this post I want to examine how the doctrine of abstract ideas is supposed, according to Berkeley, to lead to "Error and Difficulty in the Sciences ... [and] ... Scepticism, Atheism, and Irreligion."...
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Quote of the Day: Berkeley's Own Summary of the Argument from Representational Realism to Skepticism

In a previous post, I summarized Berkeley's argument against representational realism. I just came across a very good passage in the Dialogues where Berkeley himself gives a summary of his argument that representational realism leads to unpalatable skeptical consequences: It is your opinion, the ideas we perceive by our senses are not real things, but images, or copies of them. Our knowledge therefore is no farther real, than our ideas are the true representations of those originals. But as these supposed originals are themselves unknown it is impossible to know how far our ideas resemble them; or whether they resemble...
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Quote of the Day: Appearances and Judgments About Appearances

And when we question whether the underlying object is such as it appears, we grant the fact that it appears, and our doubt does not concern the appearance itself but the account given of that appearance, - and that is a different thing from questioning the appearance itself. For example, honey appears to us to be sweet (and this we grant, for we perceive sweetness through the senses), but whether it is also sweet in its essence is for us a matter of doubt, since this is not an appearance, but a judgement regarding the appearance. (Sextus Empiricus, Outlines of...
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