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

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Kapitel 4. The Reality of Primary and Secondary Qualities

Locke‘s two chief contentions as to qualities are that primary qualities are “in the things themselves“ or respectively “real“, and that secondary qualities are “nothing in the objects themselves but powers“ or respectively not in the same way real than primary qualities are. I will call these claims the reality doctrine of qualities. The reality doctrine is an integral part of Locke‘s prominent explanations on resemblance and qualities in II.viii and is intimately connected with Locke‘s chief assertions on resemblance. Obviously, the reality status of qualities matches the resemblance status of their ideas: ideas of qualities, which are real, are resemblances; ideas of qualities, which are nothing in the objects themselves but powers, are dissemblances.<173> And as with resemblance, Locke is not primarily concerned with the reality status of primary and secondary qualities in general, but rather with the “non-reality“ of sensible qualities.<174>

Yet, despite the frequency and evident importance of these depictions of qualities, Locke himself never really introduces or explains the notions of being in the things themselves, being real or being nothing in the objects themselves but powers. Apparently, for him it is a clear-cut and natural way to characterize qualities. The prevailing view is that primary qualities are conceived as real in the way properties exist in bodies and that secondary qualities are not real in this sense, since in this context they are understood as mental states or respectively properties of a perceiver. Commentators however disagree in important details, especially whether secondary qualities are the entities which Locke officially designates as secondary qualities or whether they are truly identified with the entities which he usually calls ideas of secondary qualities.<175> On the contrary, I will argue that, in principal, Locke uses his notions of ideas and qualities unequivocally and consistantly with his official declarations as they were reconstructed in the foregoing chapter. Moreover, taking into account Boyle‘s views on qualities, a historically plausible


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alternative interpretation becomes attractive which reads Locke‘s explanations as being in line with our reconstruction of Lockean resemblance and which comprehends reality doctrine and resemblance theory as two sides of the same coin. The upshot is that the ontological issue of the reality doctrine is not whether qualities exist in bodies or in sensible beings, but whether bodies genuinely possess them if they are understood in an ideal scientific perspective, namely from a perception-neutral standpoint.

In this chapter, only the reality doctrine will be highlighted, whereas both Locke‘s reasoning for the contentions and his definitions of primary and secondary qualities will be discussed in the next one. The first step is to show that key passages link the reality status of qualities with the role they play in an explanatory account of bodies and properties. Crucially, this demonstrates that secondary qualities are conceived as features of bodies and thus refutes common lines of interpretations which take the reality doctrine to relate to mental states with respect to secondary qualities. Then an alternative view will be developed by reading Locke‘s comments in the light of Boyle‘s corpuscularian theory and his argument on real qualities. The analysis discloses that the reality doctrine conceives qualities from the same perception-neutral perspective from which the resemblance theory depicts ideas of qualities. The final part discusses passages which are often understood to substantiate the usual views. It will be argued that Locke should rather be read on the backdrop of the advanced interpretation to understand his explanations as coherent.

a. The Reality of Qualities and the Resemblance of Ideas

In many passages, Locke portrays secondary qualities as powers, i. e. properties being dispositions to cause ideas, which are to be identified with microphysical primary qualities. In Locke‘s corpuscularian terms, a secondary quality is a disposition understood in terms of primary qualities of the “insensible parts“ of bodies.<176> Since according to corpuscularian theory these dispositions, or insensible parts respectively, are minute particles on the surface of bodies, the secondary quality of being yellow is conceived as


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being identical with specific microphysical minute particles which pass on motions to other microphysical particles which eventually affect our senses.<177> This understanding of qualities is significantly present when Locke makes use of corpuscularian theory in his reasoning about qualities, namely in his accounts about: the perception of a body‘s properties (§§12-13), the changing of a body‘s secondary qualities (§20), and the multiplicity of effects a body has on a perceiver (§§19 and 21). The same relationship is expressed by Locke‘s phrase that secondary qualities depend on or are reduced to primary qualities.<178> In an explanatory account of bodies, secondary qualities are dispositional properties and to be elucidated in terms of microphysical primary qualities. Note that for Locke macrophysical primary qualities can likewise be conceived as dispositions being comprehended in terms of microphysical primary qualities. Hence, the punchline of the portrayal of secondary qualities as powers or dispositions is that they are features which are highlighted by properties of a different conceptual type, namely by primary qualities. In this sense, one has to understand my way of speaking that secondary qualities are dispositions, namely that, more specifically, they are dispositions which are elucidated in terms of a different conceptual type. This depiction is likewise present in Locke‘s definition of secondary qualities:


“§10. 2dly, Such Qualities, which in truth are nothing in the Objects themselves, but Powers to produce various Sensations in us by their primary Qualities, i. e. by the Bulk, Figure, Texture, and Motion of their insensible parts, as Colours, Sounds, Tasts, etc. These I call secondary Qualities.“<179>

The first step is to realize that the characterization of secondary qualities as powers is part of a more complex depiction: secondary qualities are nothing else “in the Objects themselves“ than powers that are comprehended in terms of microphysical primary qualities. In other words, a secondary quality is a property which is in no other way “in the things themselves“ than in form of a disposition. In a later passage it becomes evident that Locke equates this way of being in the things themselves with the reality status of secondary qualities:


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“[...] whatever reality we, by mistake, attribute to them [scil. secondary qualities], [secondary qualities] are in truth nothing in the Objects themselves, but Powers to produce various Sensations in us, and depend on those primary Qualities, viz. Bulk, Figure, Texture, and Motion of parts; as I have said“.<180>

This means, secondary qualities are only in that sense real, or “non-real“ in which they are qua dispositions in the things themselves. The apparent similarity between the latter quoted passage and the definition of ’secondary quality‘ suggests that Locke means the same when defining secondary qualities as properties being nothing else in the objects themselves than a disposition. Importantly, this implies that secondary qualities are comprehended as properties of bodies when characterized as being non-real. Having said that, it becomes plain that, in fact, this is likewise entailed in the definition of secondary qualities:


“To these [scil. primary and sensible qualities] might be added a third sort which are allowed to be barely Powers though they are as much real Qualities in the Subject, as those which I to comply with the common way of speaking call Qualities, but for distinction secondary Qualities. For the power in Fire to produce a new Colour, or consistency in Wax or Clay by its primary Qualities, is as much a quality in Fire, as the power it has to produce in me a new Idea or Sensation of warmth or burning, which I felt not before, by the same primary Qualities, viz. The Bulk, Texture, and Motion of its insensible parts.“<181>

Locke points out that non-sensible secondary qualities, e. g. the propensity of fire to change the consistency of wax, are as much “real Qualities“ of bodies, e. g. a “real Quality“ of fire, as sensible qualities are. Since, usually, only primary but not secondary qualities are said to be “real Qualities“, Locke evidently does not use ’real Quality‘ in the same sense when calling primary qualities real, but with a different one which applies to secondary qualities, namely to assert that secondary qualities are real qualities in the sense of being powers. Again, it shows up: secondary qualities in general and thus sensible qualities in particular are real qua being dispositional properties of bodies which are highlighted in terms of microphysical primary qualities.

This understanding of ’real‘, and ’in the things themselves‘ respectively, corresponds to


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the way Locke uses these concepts in connection with primary qualities.<182> The argument in §§11-15, which establishes that sensible qualities are secondary qualities, suggests that primary qualities are understood as being real in so far as intrinsic or explanatory properties are real. Here Locke first expounds a corpuscularian hypothesis of sense perception according to which primary qualities are explanatory basic, i. e. according to which bodies are understood from the explanatory perspective in terms of microphysical primary qualities. And he then concludes that only the “patterns“ of ideas of primary qualities “do really exist in the Bodies themselves“.<183> Now, whatever Locke means exactly when recognizing that the patterns of ideas of primary qualities are in the bodies themselves, on the face of it, primary qualities are conceived here as properties being in the things themselves in virtue of their explanatory function. However, it would be imprecise to identify primary qualities with features being intrinsic or explanatory basic in an account of bodies and their properties. For primary qualities, as explained above, are conceptual types of features which comprise micro- as well as macrophysical properties. The primary quality figure is instantiated by both micro- and macrophysical figure. Thus, more specifically, primary qualities are real in virtue of being the conceptual type of features serving as intrinsic or explanatory basic properties in a theory of bodies.

We have seen, ’to be real‘ and ’to be in the things themselves‘ characterize the reality status of both primary and secondary qualities with respect to their role in an explanatory or scientific account of bodies. Secondary qualities are non-real or nothing in the things themselves than powers in virtue of being dispositions that are identified with primary qualities. Primary qualities are real or in the things themselves in virtue of being the features in terms of which one conceives bodies and their properties in a theory of bodies.

The analysis so far has made plain that at least in some passages the reality doctrine is about qualities conceived as properties of bodies. The reality status has something to do with their role in a scientific account of bodies and their properties, namely with them serving as intrinsic or respectively dispositional properties. The immediate impact is that these important paragraphs cannot be understood in accordance with common lines of


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interpretation. For example, Locke is often understood to ascribe reality to primary qualities in the sense that they are properties of bodies, and to deprive reality of secondary qualities in the sense that they are not properties of bodies, but rather mental states of a perceiver.<184> These commentators regard secondary qualities in the context of the reality doctrine not to be dispositions, but to be sensations, i. e. as being identical with ideas of secondary qualities. Other readings do conceive Locke‘s secondary qualities as properties of bodies, but they also assert that the reality doctrine relates truly to ideas of secondary qualities.<185> Ideas of secondary qualities are thus said to be not real in the sense that they are mental states and not properties of bodies. Both lines of interpretation view Locke‘s notions of being real and non-real alike and attribute them to the same type of entities, namely to properties respectively to mental states. Not surprisingly, among the two readings there is a corresponding similarity as to the conceptual level. In connection with the reality doctrine, predicates like ’yellow‘ are said to denote mental states: according to one reading Locke calls these mental states ’secondary qualities‘, according to the other one ’ideas of secondary qualities‘.<186>

However, in the quoted passages Locke speaks neither of (ideas of) secondary qualities being non-real in virtue of being sensations, nor of primary qualities which are real solely in virtue of being properties. Quite the contrary, secondary qualities are real qua dispositions and primary qualities are real qua intrinsic features.

Yet, it remains so far unclear how the reality status of qualities can be spelled out in the light of their explanatory role. In what follows next, I will argue that this can be done by ascribing to Locke an intelligible and historically plausible view. The key is the corpuscularian backdrop of Locke‘s quality discussion.

b. The Reality Doctrine in the Light of Boyle‘s Criticism of Real Qualities

Natural philosophers before Locke have already distinguished between primary and secondary,<187> in particular Boyle who had developed the corpuscularian hypothesis.<188> There is no need to expound Boyle‘s concept of primary and secondary qualities and his corpuscularian account in detail, but some input of Locke‘s corpuscularian background is needed to recognize the thrust of his reality doctrine.

Boyle‘s quality distinction is part of his corpuscularian theory which is a mechanical account of the properties of bodies, namely of how their properties change and how their properties are perceived. He contends that bodies are to be comprehended as a compound of smaller bodies, the corpuscles,<189> and that corpuscles have certain physical properties, e. g. shape, size and mobility.<190> These “corpuscularian“ properties are often, but not consistently called primary qualities.<191> From this explanatory perspective bodies are understood solely in terms of microphysical, corpuscularian qualities. This implies that the multiplicity of properties, which bodies have on the macrophysical level, is reduced to their microphysical, corpuscularian properties.<192> Every property of the macrophysical level is explained in terms of corpuscularian properties of the microphysical level. Since macrophysical bodies have corpuscularian properties not only if understood from the micro- but also from the macrophysical viewpoint, corpuscularian properties occur on both levels. There are both macro- and microphysical corpuscularian properties. In other words, a corpuscularian feature is conceived as a conceptual type of properties, namely as a conceptual type of the features being intrinsic according to corpuscularian theory. On the other hand, all other properties, e. g. colours, are understood as dispositional properties


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and do not have a microphysical aquivalent.<193> These features are often, but again not consistently named secondary qualities.<194>

The implications are of two kinds. First, a single corpuscle does not have secondary qualities, e. g. it is not coloured.<195> Second, even macrophysical compounds of corpuscles are conceived not to have secondary qualities in addition to their corpuscularian features. Boyle illustrates this with respect to non-sensible secondary qualities. A key fitting a lock has the power to turn the the lock and the lock has the power to be turned by the key. But, Boyle insists, “by these new attributes there was not added any real or physical entity either to the lock or to the key“.<196>

Boyle‘s substantial argument to decline Aristotelian real qualities is directly connected with his account of qualities, as the last quote already indicated. A quality is real if it is literally ascribed to bodies on the microphysical level although bodies do not have the quality from the explanatory standpoint.<197> In other words, real qualities are secondary qualities which are treated analogous to primary ones in being likewise present on the microphysical level. For example, sensible qualities like colour and taste are real qualities, if they are attributed to bodies as features being ontologically or numerically distinct from corpuscularian properties; but Boyle insists:


“there is in the body, to which these sensible qualities are attributed, nothing of real and physical but the size, shape, and motion or rest, of its component particles, together with that texture of the whole, which results from their being so contrived as they are; [...]“.<198>

To say in the Aristotelian sense that bodies are coloured, is to assign to them a real quality


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which they do not possess from the scientific viewpoint. This becomes evident in respect of single corpuscles: corpuscles are not coloured - neither from the microphysical perspective nor even from the macrophysical stage since they do not have the power to cause visual sensations. Similarly, compounds of corpuscles are not coloured, if understood from the microphysical perspective. In an explanatory account, bodies are not described in terms of secondary qualities. Of course, according to corpuscularian theory, macrophysical bodies still have secondary qualities, but only on the macro- and not on the microphysical level. The disclaimer of real qualities is not a denial of macrophysical bodies having secondary qualities, but of the existence of microphysical secondary qualities. It is an ontological thesis. This ontological contention is derived from an account that the real qualities are truly dispositions and that they therefore do not exist numerically distinct in addition to their corpuscularian properties. In Boyle‘s own words:


“And proportionably hereunto, I do not see why we may not conceive, that as to those qualities (for instance) which we call sensible, though by virtue of a certain congruity or incongruity in point of figure (or texture or other mechanical attributes) to our sensories, the portions of matter they modify are enabled to produce various effects, upon whose account we make bodies to be endowed with qualities; yet they are not in the bodies that are endowed with them any real or distinct entities or differing from the matter itself furnished with such a determinate bigness, shape, or other such modifications.“<199>

Locke‘s corpuscularian account of perceiving properties of bodies which he gives in §§12-13 goes along the lines of Boyle‘s corpuscularian theory.<200> As alluded to above,<201> in Locke‘s outline of an explanatory account, bodies are described solely in terms of primary qualities, and secondary qualities are conceived as “combinations“ of microphysical primary qualities. Now, if one reads Locke in the light of Boyle‘s discussion of real qualities, the depriving of secondary qualities of being real simply means that there are no secondary qualities on the microphysical level. In this sense it is perfectly intelligible to say: secondary qualities are not real - while maintaining that they are properties in the


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sense of dispositions. In an explanatory, microphysical description secondary qualities do not exist separately side by side with primary qualities. To the contrary, secondary qualities are to be identified with microphysical primary qualities. The former are not numerically distinct from the latter. This reading of the reality status of qualities and of Locke‘s use of “real“ complies with Boyle‘s use of ’real‘ when saying that a non-sensible quality is not “any real or physical entity“ or that sensible qualities are not “any real or distinct entities or differing from the matter itself.“ By contrast, primary qualities of the macrophysical level are real in the sense that they re-appear on the microphysical level. To be more precise, since a primary quality comprises both micro- and macrophysical features, primary qualities are real because bodies possess them from the scientific standpoint.

Thus, what Locke is up to is to decline the popular belief amongst laymen,<202> Aristotelians and alchemists that sensible qualities are in the same way irreducible as corpuscularian properties are.<203> Primary qualities do appear on the microphysical level, but secondary qualities disappear. Not to make this distinction is to give a false, very misleading account of how things are. Locke‘s claim of the non-reality of secondary qualities can be made intelligible on the background of contemporary scientific discussions. Macrophysical primary qualities are real because from the explanatory perspective they are conceived in terms of the same conceptual type, whereas secondary qualities are non-real because they are explained in terms of a different type of properties.

This way to comprehend Locke illuminates both why the reality status of qualities is linked with their explanatory role as intrinsic or respectively as dispositional features and why qualities are understood in terms of “conceptual types“. The nexus between the reality status of qualities and their explanatory role makes likewise plain why in these passages Locke is concerned with an explanatory account of bodies, namely with corpuscularian theory: the reality status of properties relates to the way bodies are conceived in a scientific description of them.

Crucially, on the face of it, other passages have to be understood in the same light. In his discussion of qualities, Locke‘s main objective is to show that contrary to popular opinion


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sensible qualities are not real, i. e. that they are only as much real as other secondary qualities are. To underpin his contention, he draws an analogy between sensible qualities and other secondary ones, namely mediately perceivable features like the propensity of the sun to melt wax. To come to grips with the analogy, Locke‘s distinction between immediately and mediately perceivable secondary qualities has to be introduced first.

The sub-division of secondary qualities between immediately and mediately perceivable secondary qualities is implicitly introduced in the definition of secondary qualities, but stated explicitly at the end of the chapter.<204> The secondary quality of a body is mediately perceivable if it is understood as the property which causes a sensation of a change of features which another body possesses. Mediately perceivable secondary qualities are therefore propensities of bodies to cause property changes in other bodies; and they are identified by the corresponding change of sensation which goes hand in hand with the property change. For example, the capacity of the sun to melt wax is grasped as the property of the sun which causes the change of perceiving wax first to be hard and then to be fluid. Similarly, the power of wax to be melted by the sun is that feature of wax which is causally involved in the change of perceiving wax first to be hard and then to be fluid. On the contrary, a secondary quality is immediately perceivable if it is identified or ascribed to a body directly by a sensation of the secondary quality. For example, sensible qualities like colours are properties causing a visual perception by which a particular colour is specified.

Coming back to the comparison of the reality status between sensible qualities and mediately perceivable secondary qualities, §24 for example, entails the proposed reading of the reality doctrine. According to Locke, one commonly regards sensible qualities as real qualities in the things themselves, but mediately perceivable qualities as nothing but powers:


“For the Second sort [scil. immediately perceivable qualities], viz. The Powers to produce several Ideas in us by our Senses, are looked upon as real Qualities, in the

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things thus affecting us: But the Third sort [scil. mediately perceivable qualities] are call‘d, and esteemed barely Powers.<205>

Rejecting the belief that sensible qualities are real, Locke points then out that one has to conceive them like mediately perceivable features, namely as powers and not as real qualities. In both cases one has to comprehend secondary qualities in terms of (microphysical) primary qualities: “ [...] these two later sorts of Qualities are Powers barely, and nothing but Powers, relating to several other Bodies, and resulting from the different Modifications of the Original Qualities“.<206> Locke illustrates his point by qualities of the sun. The sun‘s power to melt wax is a mediately perceivable property which is regarded solely as a power or disposition of the sun:


“But when we consider the Sun, in reference to Wax, which it melts or blanches, we look upon the Whiteness and Softness produced in the Wax, not as Qualities in the Sun, but Effects produced by Powers in it“.<207>

In other words: when conceiving the power of the sun to melt wax with reference to the effect caused in the wax, we do not understand the sun to be soft; rather the softness is seen as an effect produced in the wax by the sun‘s power. In short, softness is not attributed to the sun, but to the wax. That is, one does not elucidate a mediately perceivable property in terms of its effect by which one identifies the property. Instead, one comprehends the sun‘s power to melt wax in terms of microphysical primary qualities. Locke moves then on to assert that sensible qualities have to be understood in the same way. This means, not only mediately but also immediately perceivable properties are dispositions which are to be conceived in terms of primary qualities. The comparison between mediately and immediately perceivable features thus establishes that for Locke sensible qualities are not real qualities in virtue of being dispositions.<208>


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This means, Locke links again the reality status of secondary qualities with them being dispositions: they are not real qualities because they are to be identified with primary qualities. And Locke charges his opponents to make the mistake to ascribe a secondary quality to bodies from an explanatory standpoint. But a secondary quality, he maintains, is of a conceptual type in terms of which one only grasps the secondary quality, but in terms of which one does not elucidate the secondary quality in a scientific account of bodies. Concepts of secondary qualities denote properties in virtue of the sensations they produce, concepts of primary qualities depict properties in virtue of their existence from the causal standpoint. To confuse this, is to take sensible qualities as real qualities or respectively to attribute sensible qualities to bodies on the microphysical level.

To sum up, Locke‘s analogy serves to establish that sensible qualities are like other secondary qualities with regard to a scientific understanding of them. There is nothing soft in the sun which causes the softness of wax. Correspondingly, there is nothing hot in the sun which causes the sensation of heat. Of course, in the sun there is the disposition to melt wax and to warm, but these properties should not be understood in terms of softness or warmth. Secondary qualities are features of bodies which are to be elucidated in terms of primary qualities; from the explanatory standpoint one should not conceive secondary qualities in terms of the conceptual type in terms of which one depicts them as secondary qualities. As to secondary qualities, one can grasp a feature either with reference to our mental representation of them as produced in sensation, i. e. in terms of a secondary quality or with reference to our scientific understanding of them, i. e. in terms of primary qualities. By contrast, primary qualities - whether micro- or macrophysical


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ones - are properties which are understood in the same terms whether with respect to our sensations or to our explanatory account of them.

Importantly, the analogy between mediately and immediately perceivable features moreover makes plain that the reality status of qualities is not related to their explanatory role in any account of bodies and their properties. Rather, the reality status of a quality is linked with its role in an account of bodies with respect to our mental representations of them. To say that secondary qualities do not exist on a microphysical level is not simply to claim that they are omitted in a description of bodies in some scientific explanation of their properties or that secondary qualities do not perform the role of being explanatory basic in some kind of theory. Instead, Locke prefers to conceive bodies in the language of microphysics rather than in our everyday language of secondary qualities, because to portray bodies in terms of primary qualities is to comprehend them independently of any particular way we represent them mentally. One can illustrate this again in corpuscularian terms.

According to the corpuscularian picture, a body has a multiplicity of ways to affect a perceiver, namely to cause a multiplicity of mental representations of the properties of the body. And since one grasps the features of bodies by one‘s mental representations, one depicts bodies by a multiplicity of mental representations. In other words, there is a multiplicity of concepts each of which denotes a type of property being conceptually distinct. However, for corpuscularians like Locke, an explanatory account of our mental representations makes intelligible that only a smaller set of conceptually distinct types of properties are truly numerically distinct. The multiplicity of conceptually distinct types of features are ontologically reduced to the small set of primary qualities. In a theory of perception, bodies are grasped from a causal perspective, namely as the cause of all our mental representations. To depict bodies in terms of primary qualities is thus to conceive them as independent of the way they are mentally represented. Concepts of primary qualities are therefore designed to be the vocabulary with which one comprehends bodies as not being related to our mental representations. In Lockean words: describing bodies with primary qualities is to conceive them how bodies are in themselves, and not how they are in relationship to the way they affect the perceiver, i. e. to the particular way bodies are mentally represented.


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We now see: in connection with the reality doctrine Locke discusses qualities from the same epistemological perspective as he does with ideas in connection with the resemblance theory, namely from a perception-neutral viewpoint. This is not surprising, given the prominence of the corpuscularian theory of perception in Locke‘s chief argument in §§11-15 and the close ties between reality doctrine and resemblance theory. With regard to this epistemological perspective Locke depicts qualities as real or non-real. A property is real if a feature of the same conceptual type is ascribed to bodies from the perception-neutral standpoint; otherwise it is non-real.

c. Objections against Alleged Textual Evidence for Alternative Readings

If one keeps the perception-neutral perspective of the reality doctrine in mind, one can elucidate passages in accordance to the developed reading which are usually seen to establish common lines of interpretation. For most commentators, there are passages showing that Locke comprehends secondary qualities as being not real in the sense that they are sensations and not properties of bodies. At the root of this predicament Locke is viewed to mean in fact ideas or perceptions of secondary qualities when literally speaking of secondary qualities or when using words like ’yellow‘. Locke is taken to mean ideas of secondary qualities when speaking of entities which he signifies by concepts like ’yellow‘.<209> Ayers does not certify confusion, but he takes Locke to make use of an ambiguity of ’idea of secondary qualities‘ and of a corresponding ambiguity of ’secondary qualities‘. Ayers understands Locke to use ’secondary qualities‘ not only for properties but also for our ideas or sensations of them, since Locke, allegedly, declares in one passage that ’ideas of secondary qualities‘ signifies primarily perceptions of secondary qualities and secondarily secondary qualities. In particular, Ayers regards Locke‘s analogy between pain and sensible qualities to show that secondary qualities are said to be not real in the way Ayers views Locke.<210>

But the advanced interpretation can be squared with these passages. On first thought


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Locke there seems to speak of secondary qualities as if they were effects or sensations. Secondary qualities appear to be portrayed as being real only in the sense that they exist as sensations of bodies only in the mind of a perceiver. In these paragraphs Locke pursuits again his main objective, namely to show that sensible qualities have the same reality status as all other secondary qualities have. To show that the common interpretation of these passages is unnecessary and unhelpful in order to read Locke as arguing coherently, one has to keep in mind Locke‘s use of ’quality‘, namely that qualities are understood as intentional objects if qualities are said to be ideas.<211> On this backdrop the comments having typically led to the usual view can be understood in the light of the reconstructed position. Likewise, Ayers textual evidence for the alleged official ambiguity of Locke‘s notions dissolves and it becomes clear that Locke‘s pain analogy does not display that secondary qualities are mental states. Instead, the pain analogy should be read along the lines of his analogy of sensible qualities with mediately perceivable secondary qualities. I begin with II.viii.16:


“§16. Flame is denominated Hot and Light; Snow White and Cold; and Manna White and Sweet, from the Ideas they produce in us. Which Qualities are commonly thought to be the same in those Bodies, that those Ideas are in us, the one the perfect resemblance of the other, as they are in a Mirror; and it would by most Men be judged very extravagant, if one should say otherwise. And yet he, that will consider, that the same Fire, that at one distance produces in us the Sensation of Warmth, does at a nearer approach, produce in us the far different Sensation of Pain, ought to bethink himself, what Reason he has to say, That his Idea of Warmth, which was produced in him by the Fire, is actually in the Fire; and his Idea of Pain, which the same Fire produced in him the same way, is not in the Fire. Why is Whiteness and Coldness in Snow, and Pain not, when it produces the one and the other Idea in us; and can do neither, but by the Bulk, Figure, Number, and Motion of its solid Parts?“<212>

As the beginning of §16 indicates, the subsequent fire example is supposed to highlight the denial that ideas of sensible qualities like hot, white, cold and sweet are “the perfect resemblance[s]“ of these qualities.<213> Thus, given our reading of ’resemblance‘, if Locke asks whether those ideas are in the bodies which cause these ideas, he asks whether the


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type of property which is ascribed to the body as the idea‘s content is also ascribed to the body on the microphysical level in an explanatory account. Locke insists in the fire-example that warmth, coldness, and other sensible qualities are not to be ascribed to fire on the microphysical level just as one does not do it in the case of pain, since in both cases one conceives the property as dispositions in terms of primary qualities. Conceptually speaking, there is nothing “like“ the idea of a secondary quality in the fire. Locke moves then on in §17 to restate his point:


“§17. The particular Bulk, Number, Figure, and Motion of the parts of Fire, or Snow, are really in them, whether any ones Senses perceive them or no: and therefore they may be called real Qualities, because they really exist in those Bodies. But Light, Heat, Whiteness, or Coldness, are no more really in them, than Sickness or Pain is in Manna. Take away the Sensation of them; let no the Eyes see Light, nor the Nose Smell, and all Colours, Tastes, Odors, and Sounds, as they are such particular Ideas, vanish and cease, and are reduced to their Causes, i. e. Bulk, Figure, and Motion of Parts.“<214>

Let us first become aware of the different aspects which are clearly mentioned. First, he identifies secondary qualities with primary ones of the microphysical level: “[Secondary qualities] are reduced to their Causes, i. e. Bulk, Figure, and Motion of Parts.“ Second, Locke compares the reality status of sensible qualities with that of other secondary qualities which both are opposed to the reality status of microphysical primary qualities (cp. the first two sentences). All the ingredients of Locke‘s reality doctrine are present. Now, the alleged problem of interpretation arises with respect to the first part of the second sentence. There, Locke seems to ascribe to secondary qualities the existence conditions of ideas of secondary qualities and thus to equate the former with the latter. Does he not assert that there are no secondary qualities, if one does not perceive them, and that they are thus reduced to primary qualities? Does he not identify secondary qualities with what he calls at other places ideas of secondary qualities?<215>

However, Locke speaks very carefully of secondary qualities vanishing only in so far “as they are such particular Ideas“. Thus he does not simply equate secondary qualities with


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our ideas of them. He does talk about the reduction of secondary qualities and of their non-existence if they are not perceived, but only with respect to secondary qualities in so far as they are ideas: “Take away the Sensation of them; ... and all [secondary qualities], as they are such particular Ideas, vanish and cease, and are reduced to their Causes, i. e. [primary qualities].“ That is, if one does not perceive secondary qualities, they vanish in so far as they are ideas. We can elucidate this on the backdrop of the advanced reading.

Certainly, Locke is pressing his point, and confuses the reader by pushing his rhetoric over the edge of immediate comprehensibility. But he does so only to stress the issue of the reality of microphysical primary properties and the non-reality status of secondary qualities: bodies have a figure, but not a colour - if they are conceived as being independent from the way we represent them. Locke maintains: if one understands secondary qualities of bodies independently of the ideas they cause (“Take away the Sensation of them“), one comprehends secondary qualities in terms of primary qualities (“[secondary qualities], as they are such particular Ideas, are reduced to their Causes, i. e. [primary qualities].“) so that in this sense bodies do not have secondary qualities (“[secondary qualities], as they are such particular Ideas, vanish and cease“). Locke thus insists that sensible qualities are in the same way real in bodies as other secondary qualities are real in bodies: “But Light, Heat, Whiteness, or Coldness, are no more really in them, than Sickness or Pain is in Manna.“ The reality status of secondary qualities is not related to their existence in human minds, but to their existence in bodies. Secondary qualities are not said to cease to exist if they are not perceived, but that they have to be identified with primary qualities, if they are conceived not in relation to our sensations but as the causes of sensations. In the same light one has to read §18:


Ҥ18. A piece of Manna of a sensible Bulk, is able to produce in us the Idea of a round or square Figure; and, by being removed from one place to another, the Idea of Motion. This Idea of Motion represents it, as it really is in the Manna moving: A Circle or Square are the same, whether in Idea or Existence; in the Mind, or in the Manna: And this, both Motion and Figure are really in the Manna, whether we take notice of them or no: This every Body is ready to agree to. Besides, Manna by the Bulk, Figure, Texture, and Motion of its Parts, ahs a Power to produce the Sensations of Sickness, and sometimes of acute Pains, or Grippings in us. That these Ideas of Sickness and Pain are not in the Manna, but Effects of its Oprations on us, and are no where when we fell them not: This also every one readily agrees to. And yet Men are hardly to be brought to think, that Sweetness and Whiteness

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are not really in Manna; which are but the effects of the operations of Manna, by the motion, size, and figure of its Particles on the Eyes and Palate; as Pain and Sickness caused by Manna, are confessedly nothing, but the effects of its operations on the Stomach and Guts, by the size, motion, and figure of its insensible parts; [....].“<216>

At first, one might be tempted to read Locke again, as commentators usually do, to insist that: bodies have primary qualities independently of whether we perceive them, whereas bodies have secondary qualities only if one perceives them. But bearing in mind what Locke means by the reality of microphysical primary properties, he rather makes the following claims:

• our mental representation of motion depicts motion in the same terms as one would conceive motion independently of any of our mental representations of motion (“The Idea of Motion represents it, as it really is in the Manna moving“)

• the property to have the form of a circle or of a square is conceived in the same terms, whether with regard to our mental representation of them or with regard to the way manna has them from a perception-neutral viewpoint (“A Circle or Square are the same, whether in Idea or Existence; in the Mind, or in the Manna“)

• manna is conceived to have both motion and form independently of whether we attribute motion and form to manna in virtue of a mental representation of motion and form, since manna has motion and form from a perception-neutral viewpoint (“And this, both Motion and Figure are really in the Manna, whether we take notice of them or no“).

Likewise one has to read Locke when he subsequently insists: sweetness and whiteness are effects like sickness and pain and are therefore not really in the manna, since all four qualities are to be understood as effects of microphysical primary qualities of the manna. Again, one has to remember that Locke speaks here of secondary qualities in so far as they are ideas or mental representations which are indeed effects caused by the manna: qua mental representations, secondary qualities disappear if bodies are grasped from a causal perspective.

True, in this paragraph there is no straight forward reference to secondary qualities being


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dispositions as there is in the other passages where secondary qualities are qualified as ideas and as being not really in bodies. This has certainly led many readers to the view that in this context secondary qualities are mental states, namely ideas of secondary qualities. However, as we have seen at the beginning, this interpretation of the reality status of qualities does not work out for key passages. But since it is possible, one should therefore read §18 along the lines of the advanced reading of the reality doctrine. One should rather understand Locke to put his point in a confusing way, instead of being deeply confused or ambiguous about the reality status of qualities. Moreover, one should not be too strict with Locke, since §18 does not serve as his first attempt to make his point intelligible. It seems to me, in §18 Locke wants to stress the analogy of sensible qualities to pain, since he believes that the reader will concede him the non-reality status of pain. From a scientific perspective, there is literally speaking no pain in the manna - and so is no sweetness.

A similar passage can be highlighted in the same way, namely Locke‘s thought experiment of a world without perceptions in II.xxxi.2. To see this, we have to take into account the context as well, especially because it includes both the comments which Ayers reads in favour of his view as well as the utterance showing that the pain analogy has to be understood along the lines suggested here.


“‘Tis true, the Things producing in us these simple Ideas, are but few of them denominated by us, as if they were only the causes of them; but as if those Ideas were real Beings in them. For though Fire be call‘d painful to the Touch, whereby is signified the power of producing in us the Idea of Pain; yet it is denominated also Light, and Hot; as if Light and Heat, were really something in the Fire, more than a power to excite these Ideas in us; and therefore are called Qualities in, or of the Fire. But these being nothing, in truth, but powers to excite such Ideas in us, I must, in that sense, be understood, when I speak of secondary Qualities, as being in Things; or of their Ideas, as being in the Objects, that excite them in us. Such ways of speaking, [...] truly signify nothing, but those Powers, which are in Things, to excite certain Sensations or Ideas in us.“<217>

The argument begins with Locke‘s delineation of the popular belief that bodies are not only the cause of simple ideas, but that these ideas are also “real Beings“ in bodies. The


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subsequent sentences to the end of the paragraph make plain that the topic is again the reality of qualities. This indicates, at the opening of the argument Locke rejects the widespread opinion that sensible qualities are not understood as being only powers - as one should in the case of secondary qualities - but as “real Beings“ or real qualities respectively. Importantly, Locke does not critizise that secondary qualities are portrayed as features, namely as powers or dispositions, but that they are regarded as real. It thus shows up again: to be real is not a question about being a property or not, but about being what kind of property.

In the subsequent sentence Locke illustrates his claim by a comparison between pain and sensible qualities which entails the same result. The alleged difference between pain and sensible qualities like light and heat consists for Locke in the false assumption that sensible qualities “were really something in the Fire, more than a power to excite these Ideas in us“. One conceives mistakingly sensible qualities, but not pain, as real. Secondary qualities are portrayed as powers of bodies which are not real.

In the next sentence Locke reasserts that secondary qualities are only powers. The punchline is to warn the reader not to mistake his talk of “qualities“ in connection with secondary qualities as a depiction of these properties as being real qualities. This has already been indicated in the preceding sentence where Locke states that ’quality‘ is commonly applied to sensible qualities because of the belief that they are real. More importantly, at the end of the then following sentence Locke emphasizes: when saying that secondary qualities are in bodies or that ideas of secondary qualities are in bodies, he means that (ideas of) secondary qualities are nothing but powers. Given our interpretation of ’being nothing but powers‘, Locke asserts: (an idea of) a secondary quality is in a body in the way a disposition is, but not in the way a real quality is.

Having reconstructed the background, we can now turn to the thought experiment itself. Locke invites us to imagine a world without perceptions and sensible beings:


“Since were there no fit Organs to receive the impressions from the Fire, or the Sun, there would yet be no more Light, or Heat in the World, than there would be no Pain if there were no sensible Creature to fell it, though the Sun should continue just as it is now, and Mount Ætna flame higher than ever it did. Solidity, and Extension, and the termination of it, Figure, with Motion and Rest, whereof we have the Ideas, would be really in the World as they are, whether there were

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any sensible Being to perceive them, or no: And therefore those we have reason to look on as the real modifications of Matter; and such as are the exciting Causes of all our various Sensations from Bodies.“<218>

At first glance it seems again as if Locke maintained that secondary qualities are sensations of secondary qualities and that secondary qualities would not exist if there were no sensations or ideas of them. Does Locke not assert that light and heat are only in so far in a world without perception as pain is? And is pain not a mental state, i. e. an idea? If this were correct, Locke would present a thoroughly confused argument since the thought experiment is apparently introduced to establish what has been said before, namely that secondary qualities are not real in virtue of them being just powers. However, there is no need to interpret him in this way, since his comparison of pain has to be understood differently. We have just seen that in this context Locke comprehends pain as a power to cause ideas, i. e. as a feature of bodies and not of minds. Crucially, Locke says: “For though Fire be call‘d painful to the Touch, whereby is signified the power of producing in us the Idea of Pain; [...]“. Thus, when Locke imagines the reality status of sensible qualities in a world without perceptions by analogy to pain, he portrays sensible qualities as powers.

Moreover, one can easily read the thought experiment in the light of the advanced interpretation. This is indicated at the end of his reasoning where Locke draws the conclusion that primary qualities are the only types of properties in terms of which one has to describe bodies if understood as the causes of sensations: “And therefore those [scil. primary qualities] we have reason to look on [...] as are the exciting Causes of all our various Sensations from Bodies.“ That is, from the viewpoint explaining only primary, but no secondary qualities are ascribed to bodies. Correspondingly, one can understand the thought experiment as an attempt to convey the reality status of secondary qualities. Given a world without perceptions, there is no basis to conceive properties of bodies in relation to mental representations, since there are no sensible beings to have ideas. By contrast, it does make sense to describe bodies in terms of primary qualities, since they depict bodies from a perception-neutral viewpoint. The same thought is evidently entailed in Boyle‘s argument against real qualities:



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“[...] if there were no sensitive beings those bodies that are now the objects of our senses would be but dispositively [scil. dispositionally], if I may so speak, endowed with colours, tastes, and the like; and actually but only with those more catholick affections of bodies, figure, motion, texture, etc.“<219>

The point is that in a world without sensitive beings, e. g. when only one complex body like a metal or stone exists, “it would be hard to shew that there is physically any thing more in it than matter and the accidents we have already named“<220> This becomes plain in another passage as well:


“I do not deny but that bodies may be said in a very favourable sense to have those qualities we call sensible, though there were no animals in the world: for a body in that case may differ from those bodies which now are quite devoid of quality, in its having such a disposition of its constituent corpuscles, that in case it were duly applied to the sensory of an animal, it would produce such a sensible quality which a body another texture would not: as though if there were no animals there would be no such thing as pain, yet a pin may, upon the account of its figure, be fitted to cause pain, in case it were moved against a man‘s figure.“<221>

Boyle‘s punchline is that in a world without sensitive beings one may speak of sensible qualities in terms of dispositions, but there is no real basis to characterize them qua sensible qualities. In the light of this parallel, the suggested reading of Locke‘s comments appears natural.

Perhaps more importantly, the interpretation has shown that Locke‘s comparison between pain and sensible qualities does not imply that secondary qualities are comprehended as ideas in connection with the reality doctrine. Quite the contrary, the pain analogy establishes that secondary qualities are truly properties of bodies. The pain analogy serves as an argument for the claim that sensible qualities are only dispositions but no real qualities. For Locke the reader is ready to concede that pain is non-real. Pointing out the similarities between sensible qualities and pain, Locke intends to convince him or her that sensible qualities are secondary qualities and not real ones.

The analysis made plain, moreover, that Ayers is wrong in reading the passage as Locke‘s


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declaration of an ambiguous use of ’secondary quality‘.<222> According to Ayers, Locke delineates in II.xxxi.2 that ideas of secondary qualities stand primarily for perceptions in the sense of blank effects and secondarily for the powers to cause these perceptions. Correspondingly ’secondary quality‘ is taken to denote either properties or sensations in the sense of blank effects. However, this is simply not what Locke says. He conceives secondary qualities as dispositional properties and not as (simple) ideas; and simple ideas are not understood as sensations in the sense of self-representing blank effects but as representations of the property causing them in sensation.

To conclude, given a precise analysis of the nexus between the reality status of qualities and their role in a theory of mental representations on the backdrop of contemporary corpuscularian theory, one can read Locke‘s various explanations as presenting a coherent view on the reality of qualities. The reality doctrine assesses which conceptual type of properties bodies have from a perception-neutral standpoint. The reality status of a quality thus corresponds to the ressemblance status of its idea.

In the light of the parallels between Boyle‘s and Locke‘s position, the question naturally arises whether the latter simply re-states the former. Three differences indicate that Locke transcends Boyle. First, Locke has positive concept of real qualities. Whereas Boyle uses ’real quality‘ to denote unintelligible properties which are not corpuscularian, Locke refers with this term to features that exist from a perception-neutral perspective. Second, Locke develops the notion of resemblance which characterizes the relationship between two conceptions of the same properties, namely as they are conceived in mental representations and as they are conceived from a perception-neutral perspective. The third distinction relates to the topic which has already been alluded to at the end of the last chapter. The presence of corpuscularian theory in Locke‘s explanations of resemblance and qualities leads to the question whether this epistemological perspective is meant to be a specific corpuscularian one or a general, theory-neutral viewpoint applying prima facie to all kinds of theories of perceptions. I have argued that the topic of resemblance, and therefore of the reality of qualities as well, is apparantly too general to be bounded up with a particular scientific account. But the issue will finally be settled in the next chapter.


105

Another still open issue is Locke‘s argument for the reality doctrine in general and for the thesis that sensible qualities are non-real in particular. All this will be taken on in the next section as part of Locke‘s theory of primary and secondary qualities.

Fußnoten:

<173>

Cp. 137, II.viii.14f.

<174>

137, II.viii.13-16; 142, II.viii.25.

<175>

Cp. 4c.

<176>

135, II.viii.10.

<177>

545, IV.iii.13; 589, IV.vi.14.

<178>

138, II.viii.17.

<179>

135, II.viii.10.

<180>

137, II.viii.14.

<181>

135, II.viii.10.

<182>

Locke apparently means the same when saying that primary qualities are real and that they are in the things themselves.

<183>

137, II.viii.15.

<184>

Cp. Ayers (1991), I, 63. Ayers insists here that, in this context, secondary qualities are blank effects, i. e. mental states. And he depicts secondary qualities not to be real in objects in the sense that they are mental states and not properties of bodies. Cp. Krüger (1981), 80ff.

<185>

Cp. Alexander (1985). Alexander maintains, on the one hand, that secondary qualities are properties of bodies (118). And since he claims that colours (etc.) are truly ideas of secondary qualities (118) - and not secondary qualities, as I contend -, he takes the issue of colours (etc.) being real as a question of locating them correctly. Colours (etc.) are genuine properties of a perceiver, i. e. ideas, and not properties of objects causing ideas (125f).

<186>

Cp. again Ayers (1991), I, 63; Alexander (1985), 118. See notes above.

<187>

In Il Saggiatore, Galileo introduced the distinction in modern philosophy. Cp. Galileo (1968), VI, 213-372.

<188>

Boyle developed his corpuscularian theory especially in the so-called theoretical part of The Origin of Forms and Qualities. Cp. Boyle (1772), III, 14-27.

<189>

Boyle (1772), III, 16 and 22. However, Boyle uses his terminology not always consistently and also refers to unobservable compounds of corpuscles as corpuscles, 29f.

<190>

Boyle (1772), III, 16. However, it is a matter of interpretation whether Boyle‘s primary qualities comprise only shape, size, and mobility, since he also speaks of other properties, e. g. bulk. Cp. Boyle (1772), III, 16. There is no need for my argument on Locke to go into these details.

<191>

For instance, Boyle refers to primary qualities also as “essential properties“. Cp. Boyle (1772), III, 20f.

<192>

This is well illustrated by Boyle‘s famous example of a key fitting a lock. Cp. Boyle (1772), III, 18.

<193>

Boyle (1772), III, 18 and 25.

<194>

For instance, Boyle calls also sensations secondary qualities. Cp. Boyle (1772), III, 23.

<195>

Boyle (1772), III, 22: “[...] if we should conceive that all the rest of the universe were annihilated, except any [scil. any one] of these intire and undivided corpuscles ... it is hard to say what could be attributed to it, besides matter, motion (or rest), bulk, and shape. Whence by the way you may take notice that bulk, though usually taken in a comparative sense, is in our sense an absolute thing, since a body would have it, though there were no other in the world.“

<196>

Boyle (1772), IV, 18.

<197>

I do not claim that this is Boyle‘s definition of ’ realqualities‘, but that, as a matter of fact, they have this characteristic according to Boyle‘s explanations.

<198>

Boyle (1772), IV, 23.

<199>

Boyle (1772), IV, 18. Rogers points out similarities between Locke‘s and Boyle‘s views on sense perception. Cp. Rogers (1966), 210f.

<200>

Cp. Boyle‘s account of the perception of colours in The Experimental History of Colours. Cp. Boyle (1772), I, 671.

<201>

Cp. 4b.

<202>

141f, II.viii.24f.

<203>

It is not clear whether Locke has Aristotelians and alchemists in mind, but certainly Boyle has. Boyle argues against both of them especially in The Sceptical Chymist. Cp. Boyle (1772), I.

<204>

143, II.viii.26. Some commentators use a different terminology to distinguish between immediately and mediately perceivable secondary qualities, calling the former secondary and the latter tertiary qualities. Cp. Curley (1972), 141; Goodin (1992), 59-81; Wilson (1979), 143. I will not adopt this usage, since it introduces an ambivalence of ’secondary qualities‘, namely a second meaning besides Locke‘s own one.

<205>

141, II.viii.24.

<206>

141, II.viii.24.

<207>

141, II.viii.24.

<208>

But, in §24, does Locke not also speak of sensible qualities as of sensations, ideas and perceptions? Is there confusion after all? The point is to keep in mind Locke‘s previous declaration of his terminology in §8: ’idea‘ refers generally to the intentional object of sensations caused by powers; but with the proviso that ’idea‘ is sometimes also used to denote the qualities or powers which cause intentional content. To read Locke as arguing coherently, one has to interpret his talk of sensible qualities being sensations as portraying sensible qualities as powers of bodies. For, if one does not read him in this way, he would contradict himself in the very same sentence by calling at once sensible qualities both powers as well as sensations or respectively ideas: “v.g. the Idea of Heat, or Light, which we receive by our Eyes, or touch from the Sun, are commonly thought real Qualities, existing in the Sun, and something more than mere Powers in it.“ Now, as ’v.g.‘ indicates clearly in this context, the “Idea of Heat, or Light“ exemplifies that sensible qualities are powers: ’idea‘ signifies here powers or dispositions of bodies. More straight forwardly, one can read the occurrence of ’perception‘. Sensible qualities of the sun are identified as powers or properties of the sun “which are Perceptions in me when I am [effected by these powers]“. That is, given this time Locke‘s primary meaning of ’idea‘, a sensible quality is a power which is in so far a perception as it is the intentional content of a perception.

<209>

Alexander (1985), 118.

<210>

Ayers (1991), I, 63f.

<211>

Cp. 3a.

<212>

137; II.viii.16.

<213>

137, II.viii.16.

<214>

138f, II.viii.17.

<215>

Cp. 139f, II.viii.18f and 375f, II.xxxi.2. The latter passage will be discussed subsequently to the quoted one in the main text.

<216>

138f, II.viii.18.

<217>

375f, II.xxxi.2.

<218>

376, II.xxxi.2.

<219>

Boyle (1772), III, 25.

<220>

Boyle (1772), III, 22.

<221>

Boyle (1772), III, 24.

<222>

Ayers (1991), I, 63f.


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