Esser, Frederick: John Locke‘s Investigation into our Knowledge of Bodies


General Introduction

Given the structure of the Essay concerning Human Understanding, John Locke‘s theory of bodies is clearly embedded in the overall argument. The account is evidently intended to spell out the general programme of the Essay with respect to bodies, namely “to enquire into the Original, Certainty, and Extent of humane Knowledge; together, with the Grounds and Degrees of Belief, Opinion, and Assent“.<1> Locke moreover executes his overarching project as to bodies in connection with contemporary natural philosophy. This becomes manifest when he uses key terms of mechanists to express arguments, e. g. Galileo Galilei‘s and Robert Boyle‘s distinction between primary and secondary qualities. Similarly, Locke extensively discusses Boyle‘s corpuscularian hypothesis and often adopts it in his reasonings. And, moreover, he attempts to refute Cartesian and especially Aristotelian views on bodies. In fact, in virtually all passages on bodies, Locke debates or alludes to scientific accounts. Since he likewise repeatedly insists that this assessment of bodies is genuinely philosophical,<2> the topic of his account adds up to a philosophical reflection on the so-called scientific revolution, i. e. on the rise of the new, empirical sciences in the seventeenth century.

This can be further specified. In the light of Locke‘s various programmatic statements it becomes plain that the analysis of the Essay leads up to its fourth and last book being explicit on knowledge and opinion. The first book on innate notions forms the backdrop of Locke‘s own positive account and directly motivates the second book on ideas;<3> and the third book on words is justified by its contribution to the fourth one.<4> Since, moreover, the argument on knowledge first assesses contemporary knowledge to


terminate then in a conception of a science of bodies, Locke‘s comments apparently evolve to a philosophical account of natural science. This corresponds to the final chapter of the Essay where Locke classifies “All that can fall within the compass of Humane Understanding“ into three sciences of which one concerns bodies and spirits, namely natural philosophy.<5> Locke therefore understands his clarification of knowledge as to its origin, certainty, and extent in the context of bodies as a philosophical argument on natural science.

However, despite Locke‘s recurrent effort to make plain the relationship between natural philosophy and his epistemology, there is an on-going debate on what the genuinely philosophical issue of Locke‘s analysis of bodies consists in. In this work, I will develop a line of interpretation that undertakes to settle the issue. As will be argued, Locke consciously assesses contemporary knowledge in the perspective of an ideal scientific grasp of bodies and thus unfolds a philosophical framework for natural science.

This approach leads to a thorough re-examination of Locke‘s account, since the differences to other interpretations concern most prominent issues on bodies and, correspondingly, many of their crucial concepts. To indicate the chief distinctions, the characteristics of this reading will now be outlined by comparing it with competing interpretations as to central issues comprising the programme of Locke‘s theory of bodies. One can naturally differentiate between five interrelated aspects. First, I turn to Locke‘s analysis of ideas regarding substratum, qualities, and resemblance and its relationship to corpuscularian theory, the probably most hotly discussed topic.

According to Peter Alexander, for example, Locke‘s philosophical reasoning on bodies aims at establishing Boyle‘s corpuscularian theory by demonstrating that it is an adequate and plausible account of our everday experience and description of the world. Locke is conceived as an advocat of the most convincing contemporary hypothesis on bodies who not only additionally justifies, but also explains and popularizes the theory.<6> This effectively means, Locke‘s analysis is a philosophical foundation of Boyle‘s scientific hypothesis, significantly complementing Boyle‘s own experimentally based reasonings. By


comparison, Edwin McCann maintains that Locke genuinely analyses our everyday notion of body. But McCann similarly takes Locke to found philosophically the corpuscularian hypothesis in so far as that it is the sole explanatory account which is in accordance with our ordinary conceptual understanding of bodies and our commonsense views on them and their qualities.<7>

One aim of the here expounded reading is to demonstrate that Alexander and McCann misconceive the thrust of Locke‘s explanations in connection with Boyle‘s hypothesis (cp. ch. 5 on Locke‘s theory of qualities). Of course, Locke does regard corpuscularianism as the best available scientific account being in line with our everyday concepion and experience of bodies. Yet, generally speaking, Atherton rightly points out that the genuine issue is not to establish corpuscularian theory, since even in the comments on qualities, where Locke is most favourable to the theory, his is concerned with the epistemological topic of resemblance.<8> Following this approach, I intend to show that Locke rather presupposes than argues for corpuscularian theory. Locke does intend to establish the corpuscularian account as, at his time, the only intelligible conception of bodies, but he does so only because he needs the hypothesis as a premise in the argument on the epistemological issue of resemblance. Crucially, the analysis makes likewise plain that Locke‘s central claims on qualities and resemblance assess our ordinary conceptual understanding of bodies not in corpuscularian terms, but in concepts of an ideal scientific account.

Not less importantly, Locke‘s conception of this ideal scientific viewpoint will be further specified by an unorthodox analysis of what the issue of resemblance and its relationship to corpuscularian theory are (cp. ch. 3 on Lockean resemblance). This view leads to an enhanced reading of what it means that primary qualities are “in the things themselves“, whereas secondary qualities are “nothing in the things themselves, but powers“ (cp. ch. 4 on the reality of primary and secondary qualities). One substantial upshot is that Locke describes bodies from a particular epistemological perspective which coincides with an ideal scientific grasp. From this standpoint, bodies are understood in terms of being not specific for our epistemic access to the world, i. e. for the human senses or our epistemic


apparatus respectively. This perception-neutral viewpoint is crucial to understand Locke aright, since it relates to the substratum and real essences of bodies as well. To assess bodies in this ideal scientific perspective, thus seems to me Locke‘s stake in corpuscularian theory, resemblance, and the distinction between primary and secondary qualities.

This account, I contend, is in effect additionally supplemented by Locke‘s assessment of substratum (cp. ch. 2 on the substratum of bodies). The key to this reading is a detailed analysis of Locke‘s conception of substratum in the light of his corpuscularian comprehension of bodies. As will be argued, commentators do not elucidate convincingly the depiction of substratum as what gives rise to the “union of properties“, although they usually acknowledge its importance. According to the here advanced view, Locke conceives the substratum of bodies in explanatory terms which are neither confined to corpuscularian nor to any other theory. Correspondingly, one has to read Locke‘s prominent claim that one‘s idea of substratum is confused which thus turns out as an assessment of the contemporary understanding of substratum from the standpoint of an ideal scientific grasp.

Second, Locke‘s theory of bodies includes a theory of classification. Commentators typically conceive Locke‘s comments on species and essences in the light of his criticism of Aristotelian views on this subject matter.<9> Usually, one likewise takes Locke to distinguish between contemporary classifications sorting bodies in the light of rather superficial resemblances existing on the macrophysical stage and an ideal scheme sorting bodies in accordance to their similarities on the explanatory, microphysical level. By contrast, I will argue that this latter topic is the leading issue of the comments on species, on essences, as well as on archetypes. To start with archetypes, on first thought Locke‘s claim that ideas are inadequate appears to be an emphasis that contemporary ideas do not depict bodies by their real essences.<10> The explanations of archetypes however add rather up to a complex account of how our ideas are connected with the epistemic project of an ideal scientific sorting of bodies regarding their similarities on the explanatory stage (cp.


ch. 1 on ideas and archetypes). A detailed analysis of the comments on names of bodies will moreover reveal that Locke uses the distinction between nominal and real essences to express the profound difference between ordinary species and classifications, on the one hand, and an ideal scientific sorting in terms of real essences, on the other hand (cp. ch. 6 on species and essences). Both points thus establish that the aim of the argument on species is not chiefly the refutation and substitution of Aristotelian views, but rather the assessment of contemporary classifications by comparing it with an ideal scientific sorting.

This issue of ideal classification is furthermore interwoven with Locke‘s notion of real essences, I contend. In the light of his comments on archteypes, species and other topics, an unorthodox reading of real essences emerges (cp. ch. 7 on real essences). A real essence, I claim, is ascribed to a specimen as the set of features according to which the body is sorted in an ideal scientific classification. This view profoundly diverges from the prevailing one(s), but purports to show that many of Locke‘s chief arguments on bodies afford and imply the advanced understanding of real essences.<11> It thus turns out that Locke‘s assessment of contemporary classification in the perspective of an ideal sorting is essentially linked to his conceptions of archetypes and essences. And since ’real essence‘ is almost omnipresent in his account of bodies, the issue of an ideal classification is one of Locke‘s primary themes and present in many parts of his theory.

Third, there is Locke‘s language critic. Locke puts much weight onto this analysis and emphasizes its aim to refute competing views.<12> In my eyes, however, his reasoning has not yet been fully apprehended (cp. ch. 8 on imperfection and abuses). One aim of the advanced reading therefore is to highlight Locke‘s account and to make plain its significance. This leads to a substantial re-interpretation of the argument, since the proposed reading of real essences is decisive for a correct understanding. It thus becomes plain how Locke‘s language critic attempts to reject for once and for all Cartesian and


Aristotelian conceptions of a science of bodies on purely semantic grounds, paving the way for his own conception of a science of bodies.

Fourth, in his comments on knowledge Locke advances an assessment of contemporary knowledge (cp. ch. 10 on the scope and advancement of knowledge). I will argue for two claims in particular. First, to understand aright Locke‘s analysis of the scope of contemporary knowledge, one has to take into account the developed view on real essences. Both aspects are part and parcel of Locke‘s argument to determine the extent of contemporary knowledge and to propose an experimental conception for a contemporary science of bodies that enhances human knowledge.

Importantly, this assessment of contemporary knowledge is advanced on the backdrop of a conception of an ideal natural science. According to the orthodox view, Locke maintains a mathematical-like, conception of an ideal science of bodies.<13> Roughly speaking, Locke is taken to claim that one can deduce properties on the basis of knowledge of microphysical structures by discovering conceptual-like relationships holding between these microphysical features and the properties. By contrast, I will argue for the contention that Locke is committed to an axiomatic, empirical theory that allows for mathematical-like deductions of properties. The decisive difference is that in the latter case one affords comprehensive knowledge of matter and causal interactions in the first place to develop this axiomatic, empirical theory. An axiomatic theory of this kind simply represents a thorough grasp of body. Given this kind of knowledge, Locke contends, one can then deduce which specific features are possessed by bodies having a particular microphysical structure. This conception of an ideal science of bodies thus complements the account of an ideal scientific grasp of bodies from a perception-neutral, classificatory viewpoint.

The upshot is a partial re-positioning of Locke‘s place in the history of philosophy. In rough and ready terms, Locke‘s conception of an ideal account of bodies is substantially farer away from Descartes‘s rationalism and closer to Hume‘s empiricism than is usually thought. The problem with Locke‘s conception is not that it has a Cartesian, mathematical-like a priori character, but that Locke is rather naive on the question of its


material adequacy.

Finally, there is Locke‘s comprehension of knowledge as to its certainty (cp. ch. 9 on knowledge and its degrees). Commonly, Locke is perceived to advance an incoherent account, namely that his definition of knowledge does not fit with the depiction of sensitive, i. e. perceptual, knowledge.<14> By contrast, a re-interpretation of both the definition of knowledge and the portrayal of its so-called degrees show that Locke proposes a coherent view. Accordingly, in both contexts the certainty of knowledge relates to one‘s grasp of the reasons in virtue of which one recognizes the obtaining of a fact. Since the certainty of knowledge concerns Locke‘s generic portrayal of knowledge, the issue of certainty does not however specifically bear on Locke‘s theory of bodies, but pertains exclusively to the overall programme of the Essay.

The outline has made plain that the controversy concerns virtually all substantial topics regarding bodies. It has also indicated that according to the here suggested reading Locke develops a philosophical framework for natural science which: (1) specifies what a science of bodies ideally consists in, (2) assesses contemporary knowledge in this perspective, (3) advances an own conception of a contemporary science of bodies that proposes means to enhance contemporary knowledge, and (4) refutes alternative ideas of a science of bodies. I rather speak of a “philosophical framework“ than of a “philosophical foundation“ since Locke does neither attempt to establish a particular theory, e. g. the corpuscularian hypothesis, nor any fundamental laws, as Descartes respectively Kant do. Instead, Locke solely wants to provide a philosophically clarified conception of a science of bodies, the most that he believes one is able to achieve. In this sense, his theory of bodies intends to set human knowledge of bodies on the right track: by pointing out which track the right one is, that one is still at the beginning of the journey, and what the final destination of the exploration is. He thus determines with epistemological and semantic arguments: the ultimate goal of scientific knowledge and research, the actual limits of contemporary knowledge and the probable limits of knowledge in the future, as well as the objectives and means to enhance contemporary knowledge. Since the following interpretation of


Locke‘s account of bodies is structured along the lines of his own discussion, I will come back to these issues in the final chapter and delineate how in the case of bodies the general programme of the Essay evolves into a philosophical framework for a science of bodies (cp. conclusion).

A Note on Locke‘s Works on Bodies

The Essay is not only Locke‘s major work on theoretical philosophy in general, but on bodies in particular. To understand therefore aim and force of Locke‘s philosophical programme on bodies, one has to focus on the Essay even though some of its issues are likewise discussed in his correspondence with Stillingfleet or touched on in The Elements of Natural Philosophy and in Of the Conduct of the Understanding, which was originally planned to supplement the Essay. Thus, except for few places, an interpretation of Locke‘s account of bodies is chiefly concerned with the Essay. Since there are only few important differences amongst the various editions, I will generally quote the fourth one, i. e. the last one published at Locke‘s life time, if not otherwise pointed out.

A Note on Terminology

Locke himself does of course use the word ’body‘, but it is not his preferred term to denote bodies in the sense I do. He rather uses ’natural substance‘ or even the more general term ’substance‘ to refer to bodies qua natural substances. These two words, however, signify strictly speaking, not only bodies. Substances are bodies, spirits, and God; natural substances are bodies and spirits. Natural substances are furthermore contrasted with artificial substances. Natural substances are bodies qua members of a natural kind, e. g. men and gold, artificial substances are artefacts like pistols. To further complicate the matter, bodies can also be characterized as relations, e. g. men as children. The difference in this case is that only bodies qua natural substances are substances; in other words, entities being grasped as relations are not conceived as being, or respectively as possessing, a substratum. In the light of these considerations, it may not seem to be amiss to call


bodies qua natural substances simply bodies.



43, I.i.2. Cp. 44, I.i.3. Quotations from the Essay refer to the Nidditch edition. I abbreviate them as follows: page, book.chapter.paragraph. Citations from other works by Locke refer to the edition of his collected works from 1823 and are identified by the short title ’Works‘. Other references are by page number to the editions listed under ’Bibliography‘.


Cp. 43, I.i.2; 140, II.viii.22; 287, II.xxi.73; 376, II.xxxi.2;548, IV.iii.16.


102f, I.iv.25; 104, II.i.1.


401, II.xxxiii.19; 579,


720, IV.xxi.1f.


Alexander (1985), 6f.


McCann (1994), 58ff.


Atherton (1992), 122.


Cp. Ayers (1991), II, 65-77; Mackie (1975), 85-88; Woolhouse (1971), 99-105; Yolton (1970), 28-34.


Cp. Ayers (1991), II, 76.


In other words: if the real essence of a specimen were traditionally conceived, namely as comprising the microphysical properties corresponding to the nominal essence of its sort (or, alternatively, as comprising all the microphysical features a body possesses), many of Locke‘s prominent reasonings would be incoherent, conceptually confused, or would in some passages openly contradict his use of ’real essence‘.


As Locke emphasizes when introducing the Essay to the reader, he attempts to “[remove] some of the Rubbish, that lies in the way to Knowledge“ by displaying “frivolous use of uncouth, affected, or unintelligible Terms“. Cp.Epistle, 10.


Cp. Ayers (1970), 39; Ayers (1991), I, 102, and II, 147; Krüger (1973), 243-46; Mackie (1975), 100-103; Wilson (1979), 143 and 147; Wilson (1982), 249; Woolhouse (1971), 19, 25, and 136.


Cp. Alexander (1985), 282f; Ayers (1991), I, 103 and 126; Jenkins (1983), 196ff; Lowe (1995), 174; Specht (1989), 129f.

[Titelseite] [Widmung] [Danksagung] [Einleitung] [1-1] [1-2] [1-3] [1-4] [1-5] [1-6] [2-1] [2-2] [2-3] [2-4] [3-1] [3-2] [3-3] [Zusammenfassung] [Bibliographie] [Selbständigkeitserklärung]

© Die inhaltliche Zusammenstellung und Aufmachung dieser Publikation sowie die elektronische Verarbeitung sind urheberrechtlich geschützt. Jede Verwertung, die nicht ausdrücklich vom Urheberrechtsgesetz zugelassen ist, bedarf der vorherigen Zustimmung. Das gilt insbesondere für die Vervielfältigung, die Bearbeitung und Einspeicherung und Verarbeitung in elektronische Systeme.

DiML DTD Version 2.0
Zertifizierter Dokumentenserver
der Humboldt-Universität zu Berlin
HTML - Version erstellt am:
Fri Sep 27 15:57:21 2002