Theory Of Knowledge

Second Edition

Keith Lehrer

• Publisher: Routledge
• Year: 2018
• ISBN:
  9780429973895
• Edition: 2
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

In this impressive second edition of Theory of Knowledge, Keith Lehrer introduces students to the major traditional and contemporary accounts of knowing. Beginning with the traditional definition of knowledge as justified true belief, Lehrer explores the truth, belief, and justification conditions on the way to a thorough examination of foundation theories of knowledge, the work of Platinga, externalism and naturalized epistemologies, internalism and modern coherence theories, contextualism, and recent reliabilist and causal theories. Lehrer gives all views careful examination and concludes that external factors must be matched by appropriate internal factors to yield knowledge. This match of internal and external factors follows from Lehrer's new coherence theory of undefeated justification. In addition to doing justice to the living epistemological traditions, the text smoothly integrates several new lines that will interest scholars. Also, a feature of special interest is Lehrer's concept of a justification game.This second edition of Theory of Knowledge is a thoroughly revised and updated version that contains several completely new chapters. Written by a well-known scholar and contributor to modern epistemology, this text is distinguished by clarity of structure, accessible writing, and an elegant mix of traditional material, contemporary ideas, and well-motivated innovation.

1
The Analysis of Knowledge

ALL AGREE THAT KNOWLEDGE is valuable, but agreement about knowledge tends to end there. Philosophers disagree about what knowledge is, about how you get it, and even about whether there is any to be gotten. The question, What is knowledge? is the primary subject of this chapter and of this book. Why approach the theory of knowledge by asking this question? Epistemology, the theory of knowledge, and metaphysics, the theory of reality, have traditionally competed for the primary role in philosophical inquiry. Sometimes epistemology has won, and sometimes metaphysics, depending on the methodological and substantiative presuppositions of the philosopher.

The epistemologist asks what we know, the metaphysician what is real. Some philosophers have begun with an account of the nature of reality and then appended a theory of knowledge to account for how we know that reality. Plato, for example, reached the metaphysical conclusion that abstract entities, or forms, such as triangularity or justice, are real and all else is mere appearance. He also held that the real is knowable, and he inquired into how we might know this reality.¹ Aristotle, on the contrary, held that individual substances, such as individual statues or animals, are real and inquired as to how we might have knowledge, especially general knowledge, concerning these substances.² It is hardly surprising that Plato and Aristotle produced vastly different theories of knowledge when they conceived of the objects of knowledge in such different ways. Their common approach, starting with metaphysics, we might refer to as metaphysical epistemology.

The problem with this approach is that the metaphysical epistemologist uncritically assumes that we know the reality posited. He only concerns himself with what such knowledge is like after assuming the nature of reality. This leaves us with the unanswered question of how we know that reality is what the metaphysician affirms it to be and, indeed, begs the question of whether we know such a reality at all.

Other philosophers, most notably René Descartes,³ turned tables on the metaphysical approach by insisting that we must first decide what we can know about what is real and must remain skeptical about what is real until we have discovered what we can know. We might refer to this as skeptical epistemology.

It seems natural to begin with skepticism with the hope of discovering what we know and what we do not, but if we first pretend to total ignorance, we may find no way to remove it. Moreover, we shall lack even the meager compensation of knowing that we are ignorant, for that too is knowledge. Consider, for example, Descartes' attempt to found knowledge on a certain and indubitable premise. To that end he engaged in the project of doubting everything it was possible to doubt, even if the doubt was completely unrealistic or, as he said, hyperbolic. To that end he imagined a powerful demon whose object was to deceive him in all matters that were within the power of demon. The demon might deceive him about abstract matters by confusing his powers of reasoning, just as the demon might deceive him about the objects of the senses by confusing his powers of perception.

The relief from skepticism Descartes obtained was in the claim that he doubted, that he thought, and that he existed. Descartes alleged that he must think and exist to be deceived and, therefore, could not be deceived about the existence of his own thought or about his existence as a thinker. This line of thought has had its detractors. Some of them contend that Descartes was entitled only to the claim that there was a thought, for that was all that was required for the deception to occur. They concluded, therefore, that Descartes was not entitled to the further conclusion that a thinker existed.

The argument appeared to succeed concerning at least the existence of thoughts or ideas, whether or not those thoughts or ideas were true. Moreover, it also succeeds in showing thoughts with a definite content, thoughts that external objects exist, and thoughts of reasoning validly to some conclusion, for only if these thoughts exist could Descartes be deceived into thinking they were true when they were not. Though he might be deceived about the truth of his thoughts, he could not be deceived about their existence. His thoughts and ideas supplied him with a certain and indubitable starting point.

The problem tor Descartes and those who followed him in adopting the starting point of ideas, most notably Berkeley⁴ and, with an important modification concerning the nature of impressions, David Hume,⁵ was to provide some justification for supposing that our thoughts, those arising from our senses, for example, were true and that the objects of our thoughts, the external world of everyday objects, really did exist. The problem proved intractable given the restriction to a starting point of thoughts and ideas, even if the thoughts included sensory thoughts, sensory appearances or, as Hume called them, impressions. Hume argued convincingly that any attempt to construct an argument from the internal world of ideas and impressions to the external world of objects would require a premise about the correlation between the internal world and external world that was unavailable until one had justified the conclusion that external things existed, which was the very thing to be proved by the argument. When we add Hume's doubt about the power of reasoning for reaching conclusions about the external world to Descartes' demonic doubt, we appear led to skepticism about the external world.

Other philosophers, most recently, extreme materialists,⁶ have taken the opposite starting point, beginning with the assumption that we have knowledge of the external material world from observation. Beginning with the assumption that we have knowledge of the external world of matter avoids skepticism concerning the external world, which would appear to be an advantage over beginning with only the premise that we have knowledge of the internal world of ideas.

Unfortunately, this external starting point of matter has a defect exactly analogous to the internal starting point of ideas. If you start with the assumption that you know of the existence of the internal world of ideas from consciousness, you will face the intractable problem of avoiding skepticism concerning the external world of matter. For how can you prove that matter exists assuming only the existence of ideas? Perhaps there is no material world but only a succession of ideas? But if you start with the assumption that you know the existence of matter from observation, you will face the opposite problem of avoiding skepticism concerning the internal world of consciousness. For how can you prove that ideas exist assuming only the existence of matter? Perhaps there are no ideas but only the activation of neurons. Adopting either the internal starting point of ideas or the external starting point of matter leads to skepticism concerning vast domains of knowledge.

Are we then trapped between a method that uncritically assumes our knowledge of reality while assigning priority to metaphysics and one which rejects the assumption that we have knowledge and leads to skepticism? Our approach here will be neither skeptical nor metaphysical. We assign priority to neither metaphysics nor epistemology but attempt to provide a systematic and critical account of prior metaphysical and epistemological assumptions. We refer to this as critical epistemology.

We begin with commonsense and scientific assumptions about what is real and what is known. These convictions constitute our data, perhaps even conflicting data if common sense and science conflict. The object of philosophical inquiry, of which critical epistemology is a fundamental component, is to account for the data. Consider the problems that arise for a philosopher starting with the internal world of consciousness versus those for one starting from the external world of matter. The former finds himself behind an ideal veil of thought trying in vain to reason to an external world while the latter finds himself behind an iron curtain of matter trying in vain to reason to an internal world.

A critical epistemologist will eschew the bias of either starting point for a more balanced and symmetrical point of view, setting out with the premise that we have knowledge of the internal world of our ideas from consciousness and of the external world of matter from observation. Thus, a critical epistemologist, contrary to those who insist on assigning a privileged epistemic status to knowledge of the internal world over knowledge of the external world or vice versa, will insist on a starting point of symmetry between our knowledge of the internal world and the external world and thereby avoid the skeptical conclusions resulting from privileging one kind of knowledge over the other.

The account of the critical epistemologist is essentially and fundamentally critical, however. We are committed as critical epistemologists to reconsider the data of knowledge with which we begin in the light of philosophical investigation. Sometimes we explain the data and sometimes we explain the data away. For the most part, it behooves a critical epistemologist to construct a theory of knowledge explaining how we know the things we think we do, but, in a few instances, a theory may explain why we think we know when we do not. In order to explain what we do know or why we do not, however, we do well to first ask what knowledge is. Indeed, we must do so in order to evaluate the claims of either the metaphysical dogmatist or the epistemological skeptic. It is to this inquiry that we now turn.

What Is Knowledge?

Some have denied that we know what is true or what is false, and they have remained skeptics. Skepticism will have a hearing, but we shall pursue our study as critical epistemologists: We assume people have knowledge. But what sort of knowledge do they have, and what is knowledge anyway? There are many sorts of knowledge, but only one—the knowledge that something is true—will be our concern. Consider the following sentences:

• I know the way to Lugano.
• I know the expansion of pi to six decimal places.
• I know how to play the guitar.
• I know the city.
• I know John.
• I know about Alphonso and Elicia.
• I know that the neutrino is electrically neutral.
• I know that what you say is true.
• I know that the sentence 'some mushrooms are poisonous' is true.

These are but a few samples of different uses of the word 'know' describing different sorts of knowledge.⁷ If we are interested in finding out what people have when they have knowledge, we must first sort out the different senses of the word 'know.' Then we may ask our question again, once the word has been disambiguated.

In one sense, 'to know' means to have some special form of competence. Thus, to know the guitar or to know the multiplication tables up to ten is to be competent to play the guitar or to recite the products of any two numbers not exceeding ten. If a person is said to know how to do something, it is this competence sense of 'know' that is usually involved. If I say I know the way to Lugano I mean that I have attained the special kind of competence needed either to get to Lugano or to direct someone there. If I say that I know the expansion of pi expanded to six decimal places, I mean that I have the special competence required to recall or to recite the number pi expanded to six decimal places.⁸

Another sense or 'know' means to be acquainted with something or someone. When I say that I know John, I mean that I am acquainted with John. The sentence 'I know the city' is more difficult to disambiguate. It might mean simply that I am acquainted with the city and hence have the acquaintance sense of 'know,' or it might mean that I have the special form of competence needed to find my way around the city, geographically and/or socially. It also might mean that I know it in both the competence and acquaintance sense of 'know.' This example illustrates the important fact that the senses of 'know' that we are distinguishing are not exclusive; thus, the term 'know' may be used in more than one of these senses in a single utterance.⁹

The third sense of 'know' is that in which 'to know' means to recognize something as true. If I know that the neutrino is electrically neutral, then I recognize something as true, namely, that the neutrino is electrically neutral. When I recognize something as true, I recognize that something is the case, that is, I recognize something as correct information about the world. We may, being careful to use the term 'information' in an ordinary sense of the word, characterize the use of 'know' as the correct information sense of the word. The last three sentences on the list all involve this correct information sense of the word 'know.' It is often affirmed that to know something in the other senses of 'know' entails knowledge in the correct information sense of 'know.' I must have some correct information about Lugano if I know the way to Lugano; about the expansion of pi if I know the expansion of pi to six decimal places; about the city if I know the city; about the guitar if I know how to play the guitar, and so forth. Thus, the correct information sense of the word 'know' is often implicated in the other senses of the word.

In our study, we shall be concerned with knowledge in the correct information sense. The role of such knowledge in human reasoning is essential to its nature. One essential role of knowledge is the employment of it to reason to conclusions, to confirm some hypotheses and refute others. There may be states of mind that are useful to us in a var...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Dedication
• Contents
• Preface to First Edition
• Preface to Second Edition
• 1 THE ANALYSIS OF KNOWLEDGE
• 2 TRUTH AND ACCEPTANCE
• 3 THE FOUNDATION THEORY: INFALLIBLE FOUNDATIONALISM
• 4 FALLIBLE FOUNDATIONS
• 5 THE EXPLANATORY COHERENCE THEORY
• 6 INTERNAL COHERENCE AND PERSONAL JUSTIFICATION
• 7 COHERENCE, TRUTH, AND UNDEFEATED JUSTIFICATION
• 8 EXTERNALISM AND THE TRUTH CONNECTION
• 9 SKEPTICISM, VIRTUE, AND CONTEXT
• Bibliography
• Index