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In Defense of Pure Reason: A Rationalist Account of A Priori Justification (Cambridge Studies in Philosophy) Paperback – November 28, 1997

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Product Details

  • Series: Cambridge Studies in Philosophy
  • Paperback: 248 pages
  • Publisher: Cambridge University Press (November 28, 1997)
  • Language: English
  • ISBN-10: 0521597455
  • ISBN-13: 978-0521597456
  • Product Dimensions: 8.3 x 5.5 x 0.8 inches
  • Shipping Weight: 12.6 ounces (View shipping rates and policies)
  • Average Customer Review: 4.3 out of 5 stars  See all reviews (7 customer reviews)
  • Amazon Best Sellers Rank: #1,073,053 in Books (See Top 100 in Books)

Editorial Reviews


"...after reading his book we have a much better idea of the direction in which those answers must lie." Mylan Engel, Jr., Dialogue

"This book is an important contribution to the contemporary epistemological literature. The book is tightly organized, crisply argued, and sets the standard against which competing accounts must be measured. BonJour's book is rich and challenging...much can be learned from this book. It is required reading for anyserious student of the field and I entusiastically recommend it to nonspecialists as well." The Philosophical Review

"This work contains interesting criticisms of and rebuttals to opponents of rationalism. In addition it contains a bold, heady, imaginative positive account of pure reason. BonJour's bold answer consists of outlining and arguing for a theory of mental content that is nonrepresentational and at once both externalist as well as internalist. His imaginative conjecture is in the spirit of historic forms of rationalism: it is Aristotelian and Thomistic, in that the intellect in knowing necessary truths is in a sense all things; it is Hegelian in that the project critically argues for the coincidence of the real and the rational." Review of Meta Physics

Book Description

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.

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Customer Reviews

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It is a short book, and is quite limited in scope, but it was a page turner for me.
Abolaji Ogunshola
Laurence Bonjour provides a refreshingly insightful defense of "moderate rationalism" and a priori justification.
Kindle Customer
BonJour's book is quite comprehensive and refutes many of the standard critiques of rationalism.
Steve Jackson

Most Helpful Customer Reviews

15 of 15 people found the following review helpful By John S. Ryan on December 27, 1998
Format: Paperback
One of the many minor joys of reading this marvelous book is seeing Kant toppled from his rationalist pedestal and pushed into the Humean camp, where he belongs.

But the major joy, as might be expected from the title, is watching BonJour develop a cogent defense of a priori justification.

In the process, he deftly turns aside the objections of empiricism, showing that empiricist accounts themselves depend on implicit use of the a priori.

And in what may be the most significant feature of his own positive account, BonJour acknowledges that a priori justification is _fallible_ but nevertheless cannot, strictly speaking, be refuted by experience; successful refutation always depends on a priori considerations.

Finally, BonJour closes with a promising start toward an a priori theory of induction.

This excellent and workmanlike book belongs on the shelf of anyone interested in understanding and defending the power of reason.
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11 of 11 people found the following review helpful By Abolaji Ogunshola on February 20, 2002
Format: Paperback Verified Purchase
My only qualm with this book is that only a reader who has read some philosophy will find it truly accessible. It's length and scope doesn't allow the author to fully discuss many of the issues surrounding the topic of rational insight.
What is rational insight? One of the simplest examples is the syllogism: "All men are mortal. Socrates is a man. Socrates is mortal." Another example is the statement: "Something cannot be both green all over and red all over." I think that only the hardcore skeptic would deny the certainty of such insights. How do we justify/explain such insights? Here comes the rub - to justify such insights, the ability to grasp them must already be possessed by those who are justifying them and those to whom they must be justified. A point later defended by the author, and which has been defended by many rationalists, is that the structure of the world must such that these relationships are given in reality in some form.
Rather than list and categorize these insights, Bonjour mounts a wonderful defence for these insights, which he categorizes, like other rationalist philosophers, as "apriori" knowledge, or in his better term, "apriori justification". He, like other rationalists, describes them as a grasp of necessity: once thier nature is grasped and understood, people defend them by thinking and reasoning, rather than pointing to specific data given in experience.
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6 of 7 people found the following review helpful By Lord Chimp on September 10, 2005
Format: Hardcover Verified Purchase
The rationalist position, essentially that knowledge is possible purely on the basis of thinking, would never have required much defense a few hundred years ago. It had always been taken for granted that knowledge could be given a priori justification, without appeal to sensory perception. The anti-rationalist position is a difficult one: indeed, it seems that any meaningful denial of this claim would itself be a priori. Yet this fact has not dissuaded countless intellectuals from either severely disarming a priori justification or rejecting it outright. So, in my view the primary strength of BonJour's work here is to show that all rejections of synthetic a priori justification implicitly depend on synthetic a priori arguments themselves. This is apparent in BonJour's challenges to moderate empiricism, linguistic analysis, and the radical repudiation of apriorism by Professor Quine and his followers. The defensive aspect of this book demonstrates that a rejection of a priori reasoning results in a rejection of reason itself, a position that is untenable if not an outright performative contradiction. Some critics will ultimately latch on to the argument that appeals to a priori justification are ultimately question-begging. I do not find this view plausible, since such objections are also principally a priori in nature.

BonJour's critique of Kant's epistemology, showing him to be closer to empiricism than rationalism, is pretty much on the mark, because Kant's theory of knowledge applies only to one's own subjective categories and not reality in sich. (I believe a constructivist defense of Kant's philosophy can be made, but it requires that a bridge be made between the mind and external reality, something not established by Kant himself.
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4 of 4 people found the following review helpful By Steve Jackson on January 31, 2004
Format: Paperback
Laurence BonJour has written an outstanding defense of "pure reason", i.e., the idea that the human mind can, by way of rational insight, arrive at certain truths about the nature of reality. These truths are known "a priori" and do not rely on the senses for their justification. The most obvious examples of a priori knowledge are the laws of logic and mathematics. Although certain a priori truths may have some empirical content (for example, the statement that something can't be all red and all green at the same time), even these truths are not justified on empirical grounds.
This view is, broadly speaking, called rationalism and is the dominant position in the history of philosophy. Not only was it advocated by explicit rationalists such as Plato, but also philosophers considered empiricists, such as Locke and Aristotle, were rationalists. It wasn't until Hume and his followers that rationalism went challenged. (Prof. BonJour has an interesting take on Kant, whom he places within the empiricist tradition.) In our day, rationalism has been defended by many distinguished (and diverse) philosophers such as Brand Blanshard, A. C. Ewing, Gordon Clark, and Roderick Chisolm.
Prof. BonJour elaborates on the standard rationalist argument that any attempt to build a rigorously empirical epistemology must ultimately depend on a priori insight. Take the above statement that something can't be all red and all green at the same time. How many examples of red and green objects would we have to observe to come to that conclusion? How would we know that we have made enough observations to be confident in our conclusion? In addition, how can we come to the conclusion given that nothing is entirely red or entirely green?
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