SIBLES, OR " PRIMARY " SENSE QUALITIES VINDICATED.

 We

are now in a position to answer the questions : What can we know

with reasoned or philosophic certitude about the qualities and

nature of the domain of reality which has already (109-1 1) been

proved to be really external to and distinct from the conscious

perceiving mind ? 1

I. We can know that this domain of reality is substantial, or

endowed with the substance-mode of being. For we have proved

it to be really distinct from, and not a mere phenomenon in, the

perceiving subject. Therefore it must exist in itself?

II. We can know (a) that it has volume or three-dimensional

extension? i.e. the fundamental quality or property on account of

which we call a reality corporeal or material ; (b) that it consists

of a multitude of really and numerically distinct corporeal entities

or bodies, and specifically distinct collections of such bodies, each

individual body being endowed with shape or figure, rest or motion,

1 From the conscious, perceiving mind : we put it in that way so as to include

in the domain in question the self as corporeal and organic. Our conviction of the

unity of this latter in a concrete individuality with the mind, and of its real distinc

tion from the extra-organic or non-self universe, will be examined presently.

2 Cf. Ontology, 62, 63.

3 Not merely in the improper sense of something that can cause or produce

in us data endowed with " extensity," as the Divine Spirit does according to

Berkeley s theory, but in the proper sense of something that is itself extended, that

is an integral whole of parts outside parts (continuous or contiguous) in space. Cf.

Ontology, 83. JEANM&KE, op. cit., p. 400.

VOL II. 6

82 THEOR Y OF KNO W LEDGE

local or spatial relations and interactions ; (r) that each individ

ual perceiver s body is really distinct from the rest of the material

universe ; (d] that the " secondary " sensible qualities or " proper "

sensibles, resistance or impenetrability, heat and cold, light and

colours, sounds, tastes and smells, are qualities of the material

or corporeal substances, and therefore really exist, independently

of our perception of them, in these corporeal substances, no less

than these latter themselves and the " primary " qualities or

" common " sensibles referred to in (a) and ().

(a) That the external domain of reality has three-dimensional

extension is made manifest by rational reflection on the features

of concrete surface extensity, texture, pressure, resistance, vol-

uminousness, which characterize this domain of reality as im

mediately and directly given in concrete tactual, muscular, and

visual sensation-complexes : in other words by the same sort of

reflection as we have employed to vindicate the real externality

of the domain of external sense perception (109).

(b} Extensional or spatial discontinuity in simultaneously ap

prehended concrete, complex sense data or objects, is itself (in

the concrete) a direct datum of sense awareness. Spatially or

extensionally distinct individual sense data, marked by constant,

stable, persistent, and mutually irreducible complexes of sense

qualities (colour, size, shape, texture, taste, etc.) are constantly

appearing and re-appearing in sense consciousness. If these

directly and immediately apprehended sense data are themselves

real so is their multiplicity real. But we have proved that they

are themselves real ; therefore their multiplicity is real.

We have already shown that our complex specific or class-

concepts e.g. "gold," "apple," "eagle," "man," etc., are de

termined as to their respective contents by objective affinities in

the constitutive notes of each J (89, 91). The obvious ground of

those affinities lies in our simultaneous and successive sense

awareness of perceptually distinct and mutually irreducible sense

data embodying those distinct complexes of conceptual notes or

factors. We have established the general thesis that our abstract

and universal concepts are objectively real, that they are applic

able to, and have their concrete counterpart in, the data of sense.

1 Specific diversity, or difference in nature, among sense-data is per se an object

of intellect ; it is " sensibile per acciJcns, " being grounded in the irreducible, stable,

constantly recurring, qualitatively diversified sense data. Cf. JKANNIERE, op. cit.,

p. 406.

PERCEPTION OF SENSE QUALITIES 83

This is true, therefore, of our concepts of unity and plurality,

continuity and discontinuity, identity and distinction, " selfness"

and " otherness ". Since these abstract concepts are applicable

to the concrete data of sense, to "this gold," "this apple,"

"this eagle," " this man," simultaneously presented in sense per

ception, it follows that if these separate sense data are them

selves real, so must the concretely perceived " separateness," or

" oneness " and " otherness," or " distinction," be real. And

similarly, if the concretely perceived datum be a simultaneous

spatial plurality of " golds," or " apples," or " eagles," or " men " :

if each complex sense percept, e.g. the " gold "-percept, the

" apple "-percept, etc., be real, so must the perceived plurality in

each such percept be real.

Sense plurality, therefore, reveals the material universe as a

real, numerical multiplicity of beings. These beings we arrange

intellectually in collections or classes by means of our specific and

generic class-concepts. These concepts, grounded as they are in

such stable, mutually irreducible, constantly recurring, and quali

tatively differentiated sense data as e.g. " man," " horse," " apple,"

"gold," "water," etc., obviously give us a genuine intellectual

insight into the real natures of these material beings. For the

concepts are abstract representatives of the concrete percepts.

And while sense reveals the stable, irreducible, concrete complex

of perceived qualities, intellect apprehends it as a real substance

having a specific essence or nature as determined by the perceived

qualities. It is through the qualities revealed to sense that we

apprehend intellectually the specific natures of material realities

and arrive at their " essential " definitions. The substances, es

sences, specific natures, and specific distinctions, of things are per

se objects of intellect, and per accidens objects of sense (114).

Moreover we can apprehend intellectually the natures or essences

of material things only in so far as these are revealed to us

through sense qualities. This is the import of the scholastic

aphorism, Operatio sequitur esse ; Qualis est operatic talis est

natura. We have no direct, intuitive, intellectual insight into

their natures or essences. 1 Hence our " essential " definitions of

1 Cf. Ontology, 61-3. " How do we reach a knowledge of the specific natures

of substances ? . . . We know just precisely what their accidents reveal to us that

and nothing more. We have no intuitive insight into their natures ; all our know

ledge here is abstractive and discursive. As are their properties their activities,

energies, qualities, and all their accidents so is their nature. We know of the latter

84 THEOR Y OF KNO W LEDGE

the natures of things are really formulated in terms of properties

or qualities of those natures, and not in terms of the essences

themselves. 1 This abstractive and discursive knowledge of the

real natures of the things of sense is, of course, an intellectual in

terpretation, an " induction " from perceived data. The correct

ness of such interpretations must depend on accuracy of sense

observation, and is perfected by the " education of the senses "

through experience. Spontaneous interpretations are always

hasty and often erroneous. It is the aim of physical and natural

scientists, each in his own department, by careful employment of

the Inductive Method of research, to extend the sphere of our

knowledge of the natures of things, and of the laws of their

behaviour.

The conclusions we have reached concerning the real plurality

of the domain of sense depend on the proved validity of our in

tellectual concept of the " real distinction," especially the "major

real distinction " (as between individual and individual), and

"distinction or otherness from-the-self" (104, 109, ill). Nor

are they any less dependent on the validity of this concept if

they be established as realist supporters of the theory of mediate

sense perception establish them (i 13), by appeal to the principle

of causality. 2 Furthermore, the present thesis merely asserts the

possibility of a reasoned or philosophical certitude for the judg

ment that some of our concrete, complex perceptual unities, e.g.

"this man," "that man," "this apple," "that apple," etc., are

each a real unity, a real individual being, really distinct from

other such beings. It does not assert that whatever is a per

ceptual unity is eo ipso a real unity. While it asserts, for instance,

that I can know the piece of gold in my right hand to be really

distinct from the piece of gold in my left, it does not assert that

the perceptual unity, the unity for sense, of either piece, is the

unity of one individual being : each piece may be a multitude

of really distinct individual entities. But it does assert that

just what we can infer from the former. Operatio seqidtnr esse ; we have no other

key than this to knowledge of their specific natures." Ibid., pp. 218-19.

1 C/. ARISTOTLE, De Anima, L. i., c. i., 8. St. Thomas, De Ente et Es-

sentia, c. v. : " In rebus enim sensibilibus ipsae differentiae essentiales nobis

ignotae sunt : unde significantur per differentias accidentales quae ex essentialibus

oriuntur, sicut causa significatur per effectum suum," apud JKANNIKRE, op. cit., p.

422 n. So, for instance, when we define " man " as a " rational animal," the differ

entia " rational " really indicates what is a property of the nature rather than a con

stituent of the nature itself.

<J C/. JEANNIERE, ibid., pp. 406, 423-4.

PERCEPTION OF SENSE QUALITIES 85

although the proper application of our intellectual concepts of

"real unity or individuality," "real plurality," "real distinction,"

"real otherness," etc., is in some cases doubtful and difficult, 1

there is nevertheless in our concretely perceived distinctions of

" internal, " " external," " spatially extended " sense data, not only

adequate ground for the formation of such concepts, but also evi

dence which is seen on reflection to be adequate for some of our

spontaneous applications of those concepts, as, for example, in

the judgments that individual men, animals, birds, fishes, etc.,

are each one individual real being, and each really distinct from

the others. Similarly, although it recognizes that we may be

mistaken in judging successively repeated perceptions to be (be

cause of their objective similarity) perceptions of the same reality

(e.g. of the same individual man), or vice versa, to be (because of

their dissimilarity) of different realities (e.g. of different individual

men), as happens in cases of mistaken identity, 2 it asserts that

nevertheless the concretely perceived objective similarities and

dissimilarities between successive perceptions of complex data

that are conceptually and specifically the same ("men" for in

stance), furnish adequate intellectual evidence for reasoned certi

tude as to the truth of some, indeed most, of our judgments

of individual identification and discrimination. 3 And the reason

of all this is simply that the concrete perceptual grounds for the

concepts used in such judgments are just as clear and cogent for

intellect reflecting on their significance as is the concretely per

ceived " externality" whereby we conceive and judge this whole

domain of data to be "external " to, and "other than," the per-

ceiver (109) : so that it would be irrational and inconsistent to

accept the intellectual verdict that this domain is an "external

reality" and to reject the intellectual verdict that it is a domain

of "external realities".

The difficulties urged against the thesis that the external

universe is pluralistic^ i.e. a plurality of really distinct beings, may

be reduced to a few broad classes. First, there are the difficulties

1 C/. Ontology, 29 (p. 121) ; 31 (p. 124) ; 37 (p. 147) ; 38 (p. 151).

2 Treated in Inductive Logic as the fallacy of " mal-observation ". Cf. JEAN-

NiiiRE, op. cit., p. 423.

5 Ibid. The modern " Bertillon system " of identifying human individuals by

their finger-marks is an invaluable scientific improvement on the old-time signs of

human individual identity as embodied in the couplet :

" Forma, figura, locus, tempus, stirps, patria, nomen :

Haec ea sunt septem quae non habet unus et alter ".

86 THEOR Y OF KNO W LEDGE

urged from the standpoint of intellectualist monism : by the

Eleatics in ancient Greece and in modern times by Hegelians.

Such, for instance, is one of Zeno s well-known puzzles: "If

there were really different beings any two of them would differ

from each other only by some third reality, and this again from

each of the former by a fourth and a fifth reality, and so on ad

i n fin i turn : which would involve the absurdities of infinite number

and infinite regress. 1 Therefore all plurality must be apparent,

not real." Or again, "That in which things would differ must

be reality or being. But reality or being is self-identical and

common to all things . Therefore plurality is an illusion."

Such sophisms arise from assuming the abstract intellectual view

of reality to be adequate, from an erroneous interpretation of

the significance of the universal concept, from gratuitously as

suming the conceptual unity of the object of our abstract notion

of " being in general " to be as such a real unity.

A similar difficulty, arising from the realistic pantheism of

Spinoza, is based on a gratuitously assumed definition of sub

stance, a definition which identifies the latter with Necessary,

Self-Existent Being. 2

Then there is the difficulty arising from the anti-intellectualist

intuitionism of Bergson and his school in our own time (86). If

sense alone reveals reality as it is, and if in ultimate analysis the

data of sense are not data, but a datum, one dynamic, evolving

continuum, into which intellect alone introduces distinctions to

meet practical needs, and if all distinctions are thus subjective

and unreal, then of course, plurality is an illusion. But those

"ifs" are too directly opposed to the verdict both of senses and

of intellect to call for serious consideration here.

Finally, in Kant s theory, all plurality, in so far as it is know-

able, is merely mental or phenomenal. We have already ex

amined this general attitude in regard to intellect. We shall

return to it later in regard to the data of sense.

 We

are now in a position to answer the questions : What can we know

with reasoned or philosophic certitude about the qualities and

nature of the domain of reality which has already (109-1 1) been

proved to be really external to and distinct from the conscious

perceiving mind ? 1

I. We can know that this domain of reality is substantial, or

endowed with the substance-mode of being. For we have proved

it to be really distinct from, and not a mere phenomenon in, the

perceiving subject. Therefore it must exist in itself?

II. We can know (a) that it has volume or three-dimensional

extension? i.e. the fundamental quality or property on account of

which we call a reality corporeal or material ; (b) that it consists

of a multitude of really and numerically distinct corporeal entities

or bodies, and specifically distinct collections of such bodies, each

individual body being endowed with shape or figure, rest or motion,

1 From the conscious, perceiving mind : we put it in that way so as to include

in the domain in question the self as corporeal and organic. Our conviction of the

unity of this latter in a concrete individuality with the mind, and of its real distinc

tion from the extra-organic or non-self universe, will be examined presently.

2 Cf. Ontology, 62, 63.

3 Not merely in the improper sense of something that can cause or produce

in us data endowed with " extensity," as the Divine Spirit does according to

Berkeley s theory, but in the proper sense of something that is itself extended, that

is an integral whole of parts outside parts (continuous or contiguous) in space. Cf.

Ontology, 83. JEANM&KE, op. cit., p. 400.

VOL II. 6

82 THEOR Y OF KNO W LEDGE

local or spatial relations and interactions ; (r) that each individ

ual perceiver s body is really distinct from the rest of the material

universe ; (d] that the " secondary " sensible qualities or " proper "

sensibles, resistance or impenetrability, heat and cold, light and

colours, sounds, tastes and smells, are qualities of the material

or corporeal substances, and therefore really exist, independently

of our perception of them, in these corporeal substances, no less

than these latter themselves and the " primary " qualities or

" common " sensibles referred to in (a) and ().

(a) That the external domain of reality has three-dimensional

extension is made manifest by rational reflection on the features

of concrete surface extensity, texture, pressure, resistance, vol-

uminousness, which characterize this domain of reality as im

mediately and directly given in concrete tactual, muscular, and

visual sensation-complexes : in other words by the same sort of

reflection as we have employed to vindicate the real externality

of the domain of external sense perception (109).

(b} Extensional or spatial discontinuity in simultaneously ap

prehended concrete, complex sense data or objects, is itself (in

the concrete) a direct datum of sense awareness. Spatially or

extensionally distinct individual sense data, marked by constant,

stable, persistent, and mutually irreducible complexes of sense

qualities (colour, size, shape, texture, taste, etc.) are constantly

appearing and re-appearing in sense consciousness. If these

directly and immediately apprehended sense data are themselves

real so is their multiplicity real. But we have proved that they

are themselves real ; therefore their multiplicity is real.

We have already shown that our complex specific or class-

concepts e.g. "gold," "apple," "eagle," "man," etc., are de

termined as to their respective contents by objective affinities in

the constitutive notes of each J (89, 91). The obvious ground of

those affinities lies in our simultaneous and successive sense

awareness of perceptually distinct and mutually irreducible sense

data embodying those distinct complexes of conceptual notes or

factors. We have established the general thesis that our abstract

and universal concepts are objectively real, that they are applic

able to, and have their concrete counterpart in, the data of sense.

1 Specific diversity, or difference in nature, among sense-data is per se an object

of intellect ; it is " sensibile per acciJcns, " being grounded in the irreducible, stable,

constantly recurring, qualitatively diversified sense data. Cf. JKANNIERE, op. cit.,

p. 406.

PERCEPTION OF SENSE QUALITIES 83

This is true, therefore, of our concepts of unity and plurality,

continuity and discontinuity, identity and distinction, " selfness"

and " otherness ". Since these abstract concepts are applicable

to the concrete data of sense, to "this gold," "this apple,"

"this eagle," " this man," simultaneously presented in sense per

ception, it follows that if these separate sense data are them

selves real, so must the concretely perceived " separateness," or

" oneness " and " otherness," or " distinction," be real. And

similarly, if the concretely perceived datum be a simultaneous

spatial plurality of " golds," or " apples," or " eagles," or " men " :

if each complex sense percept, e.g. the " gold "-percept, the

" apple "-percept, etc., be real, so must the perceived plurality in

each such percept be real.

Sense plurality, therefore, reveals the material universe as a

real, numerical multiplicity of beings. These beings we arrange

intellectually in collections or classes by means of our specific and

generic class-concepts. These concepts, grounded as they are in

such stable, mutually irreducible, constantly recurring, and quali

tatively differentiated sense data as e.g. " man," " horse," " apple,"

"gold," "water," etc., obviously give us a genuine intellectual

insight into the real natures of these material beings. For the

concepts are abstract representatives of the concrete percepts.

And while sense reveals the stable, irreducible, concrete complex

of perceived qualities, intellect apprehends it as a real substance

having a specific essence or nature as determined by the perceived

qualities. It is through the qualities revealed to sense that we

apprehend intellectually the specific natures of material realities

and arrive at their " essential " definitions. The substances, es

sences, specific natures, and specific distinctions, of things are per

se objects of intellect, and per accidens objects of sense (114).

Moreover we can apprehend intellectually the natures or essences

of material things only in so far as these are revealed to us

through sense qualities. This is the import of the scholastic

aphorism, Operatio sequitur esse ; Qualis est operatic talis est

natura. We have no direct, intuitive, intellectual insight into

their natures or essences. 1 Hence our " essential " definitions of

1 Cf. Ontology, 61-3. " How do we reach a knowledge of the specific natures

of substances ? . . . We know just precisely what their accidents reveal to us that

and nothing more. We have no intuitive insight into their natures ; all our know

ledge here is abstractive and discursive. As are their properties their activities,

energies, qualities, and all their accidents so is their nature. We know of the latter

84 THEOR Y OF KNO W LEDGE

the natures of things are really formulated in terms of properties

or qualities of those natures, and not in terms of the essences

themselves. 1 This abstractive and discursive knowledge of the

real natures of the things of sense is, of course, an intellectual in

terpretation, an " induction " from perceived data. The correct

ness of such interpretations must depend on accuracy of sense

observation, and is perfected by the " education of the senses "

through experience. Spontaneous interpretations are always

hasty and often erroneous. It is the aim of physical and natural

scientists, each in his own department, by careful employment of

the Inductive Method of research, to extend the sphere of our

knowledge of the natures of things, and of the laws of their

behaviour.

The conclusions we have reached concerning the real plurality

of the domain of sense depend on the proved validity of our in

tellectual concept of the " real distinction," especially the "major

real distinction " (as between individual and individual), and

"distinction or otherness from-the-self" (104, 109, ill). Nor

are they any less dependent on the validity of this concept if

they be established as realist supporters of the theory of mediate

sense perception establish them (i 13), by appeal to the principle

of causality. 2 Furthermore, the present thesis merely asserts the

possibility of a reasoned or philosophical certitude for the judg

ment that some of our concrete, complex perceptual unities, e.g.

"this man," "that man," "this apple," "that apple," etc., are

each a real unity, a real individual being, really distinct from

other such beings. It does not assert that whatever is a per

ceptual unity is eo ipso a real unity. While it asserts, for instance,

that I can know the piece of gold in my right hand to be really

distinct from the piece of gold in my left, it does not assert that

the perceptual unity, the unity for sense, of either piece, is the

unity of one individual being : each piece may be a multitude

of really distinct individual entities. But it does assert that

just what we can infer from the former. Operatio seqidtnr esse ; we have no other

key than this to knowledge of their specific natures." Ibid., pp. 218-19.

1 C/. ARISTOTLE, De Anima, L. i., c. i., 8. St. Thomas, De Ente et Es-

sentia, c. v. : " In rebus enim sensibilibus ipsae differentiae essentiales nobis

ignotae sunt : unde significantur per differentias accidentales quae ex essentialibus

oriuntur, sicut causa significatur per effectum suum," apud JKANNIKRE, op. cit., p.

422 n. So, for instance, when we define " man " as a " rational animal," the differ

entia " rational " really indicates what is a property of the nature rather than a con

stituent of the nature itself.

<J C/. JEANNIERE, ibid., pp. 406, 423-4.

PERCEPTION OF SENSE QUALITIES 85

although the proper application of our intellectual concepts of

"real unity or individuality," "real plurality," "real distinction,"

"real otherness," etc., is in some cases doubtful and difficult, 1

there is nevertheless in our concretely perceived distinctions of

" internal, " " external," " spatially extended " sense data, not only

adequate ground for the formation of such concepts, but also evi

dence which is seen on reflection to be adequate for some of our

spontaneous applications of those concepts, as, for example, in

the judgments that individual men, animals, birds, fishes, etc.,

are each one individual real being, and each really distinct from

the others. Similarly, although it recognizes that we may be

mistaken in judging successively repeated perceptions to be (be

cause of their objective similarity) perceptions of the same reality

(e.g. of the same individual man), or vice versa, to be (because of

their dissimilarity) of different realities (e.g. of different individual

men), as happens in cases of mistaken identity, 2 it asserts that

nevertheless the concretely perceived objective similarities and

dissimilarities between successive perceptions of complex data

that are conceptually and specifically the same ("men" for in

stance), furnish adequate intellectual evidence for reasoned certi

tude as to the truth of some, indeed most, of our judgments

of individual identification and discrimination. 3 And the reason

of all this is simply that the concrete perceptual grounds for the

concepts used in such judgments are just as clear and cogent for

intellect reflecting on their significance as is the concretely per

ceived " externality" whereby we conceive and judge this whole

domain of data to be "external " to, and "other than," the per-

ceiver (109) : so that it would be irrational and inconsistent to

accept the intellectual verdict that this domain is an "external

reality" and to reject the intellectual verdict that it is a domain

of "external realities".

The difficulties urged against the thesis that the external

universe is pluralistic^ i.e. a plurality of really distinct beings, may

be reduced to a few broad classes. First, there are the difficulties

1 C/. Ontology, 29 (p. 121) ; 31 (p. 124) ; 37 (p. 147) ; 38 (p. 151).

2 Treated in Inductive Logic as the fallacy of " mal-observation ". Cf. JEAN-

NiiiRE, op. cit., p. 423.

5 Ibid. The modern " Bertillon system " of identifying human individuals by

their finger-marks is an invaluable scientific improvement on the old-time signs of

human individual identity as embodied in the couplet :

" Forma, figura, locus, tempus, stirps, patria, nomen :

Haec ea sunt septem quae non habet unus et alter ".

86 THEOR Y OF KNO W LEDGE

urged from the standpoint of intellectualist monism : by the

Eleatics in ancient Greece and in modern times by Hegelians.

Such, for instance, is one of Zeno s well-known puzzles: "If

there were really different beings any two of them would differ

from each other only by some third reality, and this again from

each of the former by a fourth and a fifth reality, and so on ad

i n fin i turn : which would involve the absurdities of infinite number

and infinite regress. 1 Therefore all plurality must be apparent,

not real." Or again, "That in which things would differ must

be reality or being. But reality or being is self-identical and

common to all things . Therefore plurality is an illusion."

Such sophisms arise from assuming the abstract intellectual view

of reality to be adequate, from an erroneous interpretation of

the significance of the universal concept, from gratuitously as

suming the conceptual unity of the object of our abstract notion

of " being in general " to be as such a real unity.

A similar difficulty, arising from the realistic pantheism of

Spinoza, is based on a gratuitously assumed definition of sub

stance, a definition which identifies the latter with Necessary,

Self-Existent Being. 2

Then there is the difficulty arising from the anti-intellectualist

intuitionism of Bergson and his school in our own time (86). If

sense alone reveals reality as it is, and if in ultimate analysis the

data of sense are not data, but a datum, one dynamic, evolving

continuum, into which intellect alone introduces distinctions to

meet practical needs, and if all distinctions are thus subjective

and unreal, then of course, plurality is an illusion. But those

"ifs" are too directly opposed to the verdict both of senses and

of intellect to call for serious consideration here.

Finally, in Kant s theory, all plurality, in so far as it is know-

able, is merely mental or phenomenal. We have already ex

amined this general attitude in regard to intellect. We shall

return to it later in regard to the data of sense.