In Defense of Pure Reason: A Rationalist Account of A Priori Justification

by Laurence BonJour

This book is concerned with the alleged capacity of the human mind to arrive at beliefs and knowledge about the world on the basis of pure reason without any dependence on sensory experience. Most recent philosophers reject the view and argue that all substantive knowledge must be sensory in origin. Laurence BonJour provocatively reopens the debate by presenting the most comprehensive exposition and defense of the rationalist view that a priori insight is a genuine basis for knowledge.

Genres: Philosophy, Metaphysics, Nonfiction

246 pages, Paperback

First published November 28, 1997

About the author

Laurence BonJour is an American philosopher and Professor of Philosophy at the University of Washington.

His areas of specialty include epistemology, Kant, and British empiricism.

Reviews

[Josh · Rating 3 out of 5]

I would give this 3.5 out of 5.

BonJour offers a defence of apriori epistemological justification.

He begins a discussion of the apriori in general, arguing it is necessary in epistemology. At least the vast majority of knowledge, even empirical, contains an apriori element. The movement from knowledge of experience to beliefs beyond immediate experience indicate this, and to think otherwise is to commit to radical skepticism.

BonJour believes a moderate rationalist account is the only hope for a non-skeptical account of apriori justification and knowledge.

He also critiques Kant's conceptions of the apriori synthetic as being closer to a moderate empiricism than rationalism.

For Kant, we know P apriori in spite of it being synthetic because the mind so operates in synthesising experience to make P invariably true within the experiential realm.

Kant offers no reason for thinking P is true in itself or knowable apriori - only P in the realm of experience (P°)

If P° is synthetic, how would this be accounted for? Offering the same account as P results in: the mind so operates to make it true that, the mind so operates to make it true that P°.

BonJour also discusses concepts of analyticity and it's relation to the apriori. He critiques reductive conceptions, like Frege's, as unhelpful as they appeal to other propositions to justify the analyticity of the one in question.

He also critiques Quine and radical empiricism as a form of skepticism.

He moves on to sketching his theory of moderate rationalism and deals with both epistemological and metaphysical objections. Interestingly he defends a platonic view of abstract entities.

BonJour then discusses the nature of thought and argues against symbolic theory of thought.

Finally, BonJour sketches an apriori justification of induction.

[Ali Reda · Rating 4 out of 5]

A good book. The first chapter explains how a priori isn't synonymous with analytic or necessary. The second and third chapters are a critique of moderate and radical empiricism, showing that the first leads to contradiction by assuming what it rejects tacitly and that the other, not only leads to contradiction, but also to skepticism. And in the fourth chapter he defines moderate rationalism as foundationalist fallible rationalism. All these four chapters were masterfully written.

But starting from the fifth chapter, things take a wrong way. He downplays the amount of disagreements that aren't resolved through a priori reflection. Then he tries to respond to some the epistemological objections to rationalism, and due to his approach being near intuitionstic, he doesn't say much in the end.

He ends the book with chapter 7, in which he tries to sketch a rationalistic justification of induction which turns out to be the foundational reverse of the pragmatic solution, so instead of saying that induction is highly likely to be true because it has the best consequences a posteriori, he says that induction has the best consequences because it is highly likely to be true a priori, or in his words "The claim, in other words, is that a chaotic world, though perfectly possible prior to the consideration of empirical evidence, is rendered extremely unlikely (in the respect in question) by the occurrence of standard inductive evidence and that it is an a priori fact that this is so".

[Trystan Hopkins · Rating 5 out of 5]

Excellent book. Well argued!