In the Essay Concerning Human Understanding, Locke insists that all knowledge consists in perception of the agreement or disagreement of ideas. However, he also insists that knowledge extends to outer reality, claiming that perception yields ‘sensitive knowledge’ of the existence of outer objects. Some scholars have argued that Locke did not really mean to restrict knowledge to perceptions of relations within the realm of ideas; others have argued that sensitive knowledge is not strictly speaking a form of knowledge for Locke. (...) This chapter argues that Locke’s conception of sensitive knowledge is in fact compatible with his official definition of knowledge, and discusses his treatment of the problem of skepticism, both in the Essay and in the correspondence with Stillingfleet. (shrink)

This paper argues that Locke has a representative theory of sensitive knowledge. Perceivers are immediately aware of nothing but sensory ideas in the mind; yet perceivers think of real external substances that correspond to and cause those ideas, and they are warranted in believing that those substances exist (at that time). The theory poses two questions: what warrants the truth of such beliefs? What is it in virtue of which sensory ideas represent external objects and how do they make perceivers (...) think of those objects? Both the epistemic and semantic issues need to be addressed. This paper urges that Locke's basic account of warrant is roughly reliabilist. The causal origin of sensory ideas assures that, in general, sense based beliefs are true. Locke defines the limit of this warrant by the theoretical point that we cannot discuss skeptical doubt without assuming the truthfulness of our perceptual faculty. Turning to the semantic question, the paper argues that ideas are mental modifications or entities. They are not intrinsically representative (satisfiable), but rather represent only by virtue of their causal origin. They merely “track” the presence of substances and their qualities. Ideas nevertheless prompt perceivers to think of their causes. This is roughly because sensory ideas have a specific mental role, namely, to serve as marks for distinguishing substances and their respective qualities for purposes of action. The paper suggests that, for Locke, the challenge posed by the semantic veil of ideas is to explain this externally directed marking function within bounds of his anti‐innatism. But it concludes that his answers to the twin questions fit together reasonably well. (shrink)

Locke Defines Knowledge at the beginning of Book IV of the Essay concerning Human Understanding as “the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas” (E IV.i.2).1 So defined, knowledge varies along two dimensions. On the one hand, there are four “sorts” of knowledge: of identity or diversity; relation; co-existence or necessary connection; and real existence. On the other hand, there are three “degrees” of knowledge: intuitive knowledge, which consists in the “immediate” perception (...) of agreement or disagreement between ideas (E IV.ii.1); demonstrative knowledge, which consists in the perception of agreement or disagreement by way of intermediate (or intervening) .. (shrink)

John Locke is probably one of the highest-regarded English philosophers, and the first of the British empiricists. His ideas on the mind and consciousness have continued to resonate throughout philosophy and philosophical thought ever since An Essay Concerning Human Understanding first appeared in 1690. James Gibson's Locke's Theory of Knowledge and its Historical Relations was first published in 1917, and saw its fourth reprinting in 1968. Here, it is made available for the first time in paperback. This hugely detailed work (...) is an invaluable collation of Locke's theories, exploring his thoughts on the problems of knowledge, the formation of ideas, causality and the self. Furthermore, Gibson also provides an in-depth historical evaluation of the effects of these theories on contemporary philosophy as a whole, and on thinkers such as Descartes, Kant and Leibniz more specifically. As such, this book is a valuable reference work for any student of philosophy. (shrink)

Locke characterizes sensitive knowledge as knowledge of the existence of external objects present to the senses, and in terms of an ‘assurance’ that falls short of the certainty of intuition and demonstration. But it is unclear how this fits with his general definition of knowledge, as the perception of the agreement or disagreement of ideas, and it is unclear how that assurance can amount to knowledge, rather than amounting to mere probability (which he contrasts with knowledge). Some contend that Locke (...) does not regard sensitive knowledge as genuine knowledge, but only honourifically calls it knowledge. In contrast, I argue that Locke holds that sensitive knowledge is knowledge, though he takes the conditions for it to be very different from the conditions for intuitive and demonstrative knowledge. It is not the assurance alone which Locke thinks qualifies sensitive knowledge as such: it is also the fact that the assurance arises from the actual employment of the senses upon external objects, and the fact that the senses do not generally deceive us, which he thinks qualifies sensitive knowledge as genuine knowledge. That there is a (tacit) form of externalism in Locke's account of sensitive knowledge is the main thesis of this paper. (shrink)

Given his representationalism how can Locke claim we have sensitive knowledge of the external world? We can see the skeptic as asking two different questions: how we can know the existence of external things, or more specifically how we can know inferentially of the existence of external things. Locke's account of sensitive knowledge, a form of non-inferential knowledge, answers the first question. All we can achieve by inference is highly probable judgment. Because Locke's theory of knowledge includes both first order (...) psychological and second order normative conditions, sensitive knowledge can be non-inferential and less certain than intuitive and demonstrative knowledge. (shrink)

Locke seems to hold that we have knowledge of the existence of external objects through sensation. Two problems face Locke's account. The first problem concerns the logical form of knowledge of real existence. Locke defines knowledge as the perception of the agreement or disagreement between ideas. However, perceiving agreements between ideas seems to yield knowledge only of analytic truths, not propositions about existence. The second problem concerns the epistemic status of sensitive knowledge: How could the senses yield certain knowledge? This (...) essay argues that the key to solving both problems is Locke's claim that simple ideas are all real, adequate, and true. This explains why, on Locke's view, we have certain knowledge through the senses. It also explains how sensitive knowledge can consist in perceiving an agreement between ideas: perceived agreements among simple ideas of sensation are guaranteed to track relations that obtain among really existing things. (shrink)

Although recent epistemology has been marked by several prominent disagreements – e.g., between foundationalists and coherentists, internalists and externalists – there has been widespread agreement that some form of fallibilism must be correct. According to a rough formulation of this view, it is possible for a subject to have knowledge even in cases where the justification or grounding for the knowledge is compatible with the subject’s being mistaken. In this paper, I examine the motivation for fallibilism before providing a fully (...) general account of the view. I conclude by looking at the two major difficulties for fallibilism: the Gettier problem and the lottery paradox. (shrink)

This is a review of Roger Woolhouse's biography of Locke.

Locke claims that we have sensitive knowledge of the external world, in virtue of the fact that simple ideas are real, true, and adequate. However, despite his dismissive remarks about Cartesian external-world skepticism, Locke gives us little to go on as to how knowledge of the external world survives the fact of perceptual error, or even how perceptual error is possible. I argue that Locke has an in-principle problem explaining perceptual error.

Since Edmund L. Gettier reminded us recently of a certain important inadequacy of the traditional analysis of "S knows that p," several attempts have been made to correct that analysis. In this paper I shall offer still another analysis (or a sketch of an analysis) of "S knows that p," one which will avert Gettier's problem. My concern will be with knowledge of empirical propositions only, since I think that the traditional analysis is adequate for knowledge of nonempirical truths.

This book is available either individually, or as part of the specially-priced Arguments of the Philosphers Collection.

The primary aim of this essay is to explain the central elements of Locke's theory of knowledge. A secondary aim arises from the official definition of knowledge introduced in the opening lines of book IV. Though Locke's repeated statements of the definition are consistent with the initial formulation, the consensus view among commentators is that that official definition is in tension with other book IV doctrines. My broader interpretation involves an effort to render the various doctrines consistent with the official (...) definition. The order of discussion: Section 1 explicates the definition of knowledge. Section 2 explains two main divisions of knowledge – namely, its three degrees, and the four sorts of knowable truths. In Section 3, I consider whether Locke understands knowable truths on a model of analyticity. Section 4 addresses potential problems about the objectivity of knowledge, given Locke's account. Section 5 focuses on external world knowledge – Locke calls this "sensitive knowledge" and it poses special difficulties for the official definition of knowledge. (shrink)