that 2 x 2 = 4, that the earth attracts stones, that every effect
has a cause : these are cognitions and objectively valid, yet
98 Elements of General Philosophy. [LECT.
not sense- objects ; I do not say, without relation to sense at
all, but not involving sense as such. Something may be
a fact about a particular object or not a fact, but as fact it
must hold for all. Do I know objectively ? Then I must so
think that you can think it too. I know nothing really unless
I can show that you are capable of knowing it as well as I.
We must not imagine there is any objectivity without a
subject; knowledge always involves a knower; still it is
possible for me to put together in my mind a synthesis which
will not hold good for any but myself; but then I cannot give
grounds for it to other people, so that it has no objective
validity. Suppose I said, ' The effect always goes before its
cause' this would be an example of a cognition lacking
objective validity \ No account which fails to bring forward
this aspect of knowledge grapples with the question of the"
nature of knowledge ; it may contain good psychology, but
it must fall short in philosophy.
How the Problem has been met.
We see, however, that if we have to find subjective repre-
sentations which can be set forth in such a way as to appeal
to all consciousnesses, it is not an easy task. AH earnest
philosophers have faced it, and I want now to give a notion
of how, from different points of view, this definition of the
conditions of knowledge has been met. This fact constitutes
the central problem that knowledge is so held that other
minds are viewed as participating in it, and that it is com-
municable to others. Distinctively intellectual philosophy
has always been concerned with the problem, meeting it for
1 Cf. Bain, p. 201, sec. 7. That which he here gives as the
distinctive feature of perception of a sense-object applies equally well
to all objective knowledge.
XL] Elements of General Philosophy. 99
the most part from the side of the chief factor or factors in
Here we are at once confronted by our antithesis of
Rationalism and Experientialism, or Sensationalism as, in
its first form, the latter doctrine may be called. According
to the former, knowledge is wholly explicable from Intellect
or Reason (VMS); according to the latter, knowledge is
wholly explicable from Sense or Sense-experience. And
according to a third position knowledge is explicable from
The antithesis to the word Rationalism in the fullest sense
is given by the word Sensationalism. If Rationalism is the
doctrine of reason, which is one kind of mental function,
Sensationalism is the doctrine of sensation, another kind
of mental function. Again, experience may mean bare
sense-experience, or sense ordered by reason or intellect to
form knowledge. Nevertheless Experientialism is on the
whole the more accurate term, since no theory of knowledge
was ever pure Sensationalism.
Plato naturally took the extreme doctrine of Intellectualism,
or Rationalism. Sense, he said, is only a hindrance to
knowledge ; knowledge involves an ignoring of sense. Know-
ledge is the grasping of ideas with the intellect which never
were in sense, were never got from sense, and which therefore
the mind must have brought wiih it ; it consists in the mind's
possession of innate ideas originally. (He does not use the
word 'innate,' but he teaches the doctrine.) Plato was
a poet as well as a philosopher, and clothed his philosophical
ideas in poetical form. Mythically sometimes and mystically
always he expresses the doctrine of knowledge as reminiscence
ioo Elements of General Philosophy. [LECT.
of ideas not formed from sense, but brought from a state of
prior existence. In a previous existence men had converse
with Ideas. Now they see through a glass darkly, but there
was a time, and again will be, when, freed from matter or
sense, man will see face to face. Plato's theory of knowledge,
then, is a general negation of the import of sense is a
denial that sense can be sublimated into knowledge.
This tendency has been reproduced throughout the history
of thought, especially at the beginning of the modern period.
Descartes, though he takes sense as a factor of human being,
seeks to explain knowledge out of relation to sense, and
considers it apart from sense. With Rationalists first and
last the burden of the story has been that in knowledge there
is obviously something that sense can give no account of
that there are in it notions out of all relation to sense, as fo"r
instance ' Cause.' Here is a notion necessary to our know-
ledge, yet do any of our senses give us an idea of cause as
cause ? Obviously not, yet we know what cause is. ' Sub-
stance ' is another such notion. We come to know by sense
this, that, or the other affection which objects are said to
cause in us; but how do we come to know substance as
something seemingly apart from us ?
Hence it was that Plato looked for some other source to
explain knowledge, and found one so fruitful that he denied
the value of sense. This source was Reason. Reason knows
by way of ideas, and as there was no possible account he
could give of how these ideas arose in us, he did not hesitate
to imagine that we are carrying on in this life a life that has
been begun before, and in a previous stage of which we got
our ideas. How much of this was philosophy, how much
only poetry, it is hard to say ; but we get out of the Dialogues
a positive doctrine of Innate Ideas, viz. that the mind comes
XL] Elements of General Philosophy. 101
into the world with a certain means of knowing in its original
constitution. I, according to this view, supply for myself the
idea of cause by the constitution of my mind.
Aristotle as Conciliator.
In Plato's time the opposite doctrine had already sprung
up, viz. that knowledge is only sense transformed. Later on
this found pronounced upholders in the Epicureans, the
Stoics and some of the Sceptics. To a certain extent this
antithesis was represented and headed by Aristotle, yet not in
extreme opposition. He occupied a middle ground, acting as
a kind of conciliator between the Platonic doctrine and
Experientialism. Never one-sided, he saw the truth in both
aspects ; hence his great influence on succeeding ages. Those
have judged him superficially who, with Coleridge, have said
that every man is a Platonist or an Aristotelian. The
expression that mind is a smooth tablet or tabula rasa occurs
in Aristotle ', but he is no Sensationalist. He does not say
that knowledge can be explained from sense, but he does
say that it cannot be explained without reference to sense.
Neither is it possible to make him out to be an Experientialist
of the modern type, as Grote does. There are passages in
Aristotle which must be interpreted as implying independence
in the intellect as a factor of knowledge. By likening the
mind to a tablet written on by experience he meant only that
the Nous was not a fixed body of innate principles, but
something potential which can be developed by way of
experiential realisation. We are provided with such con-
ditions of thought as will enable us to frame ideas in
1 De Anima, Bk. Ill, ch. iv : ' We must suppose, in short, that the
process of thought is like that of writing on a writing-tablet on which
noihirg is yet actually written.' E. Wallace's transl. I'tfi'fi, p. 230.
io2 Elements of General Philosophy. [LECT.
connexion with the gradual growth of our experience 1 . It
is surprising how Aristotle had begun to conceive how sense
becomes worked up by certain definite laws into those cogni-
tions which seem furthest removed from sense.
Most of the Schoolmen, as we have seen, followed Aristotle,
but assigned perhaps greater predominance than he did
to the intellectual factor, and were apt to bring in ' innate
ideas.' Some were pure Intellectualists, declaring sense to
be of no account for knowledge. The greatest of them,
Aquinas, contended for the importance of sense, but he too
admitted innate ideas as co-factors in knowledge.
Bacon outside the Controversy.
Bacon is of no importance for this question. He is a
methodologist. He sought for a ' method of discovery,' but
prefaced it by no psychological or critical investigation (I use
' critical ' here in the Kantian sense), nor did he view the
question from the subjective point of view as Descartes did.
Had he gone into the question, he must have been a
Sensationalist. He speaks of sense as a source of knowledge,
but he was no metaphysician.
Descartes was more of a metaphysician than a theorist of
knowledge. He made no attempt to give a detailed theory
of knowledge, nevertheless the philosophical position he took
up has influenced thought till the present day. To him as
to Plato sense is the antithesis of knowledge, and is to be
discounted and banned as an illusion and a show. He fell
back upon the doctrine that we have innate ideas of God,
1 De An. Bk. Ill, ch. iii.
XL] Elements of General Philosophy. 103
substance, cause, &c., and interpreted it in a definite way.
As a discoverer in mathematics and physics, Descartes came
to terms with sense. As a metaphysician he revived and
maintained the pre-existing doctrine of Innate Ideas, though
in later life he modified it. He distinguished in all mental
states three classes of ideas : (r) Innate, (2) Adventitious, and
(3) Factitious or Imaginary Ideas. The last involve a definite
mental construction that can be traced. Adventitious
ideas come by way of sense. But he insists that there
are certain definite concepts or notions which are in no
respect adventitious, but are imprinted on the mind from
the first as part of its original constitution. Chief among
these is the idea of God. On this idea he lays great stress ;
it plays an important part in his whole philosophy. We
know what we mean when we use such a term, yet the idea
involves no element of sense.
Intuition and Idea in Descartes.
Another word which Descartes is more especially inclined
to use is ' Intuition.' Whenever the knowledge which he
cannot conceive to come by way of sense assumes the form
of propositions, of the truth of which we are absolutely sure,
he uses this term. Through his initiative it has come to be
more and more opposed to sense-experience, and thus
diverted from its original meaning of inspection, vision, direct
apprehension, such as we have in sense. Some philosophers
distinguish between ' pure ' and ' empirical ' intuition, the
latter expressing the original meaning. We shall revert to
this in dealing with Kant. The student, by the way, should
avoid confounding intuition with instinct the primitive
power of conceiving and judging with the primitive tendency
or ability to perform certain acts, unlearned action, or action
104 Elements of General Philosophy. [LECT.
prompted by knowledge that is not got by experience. There
is a relation between the two ; intuitions may involve activities ;
instincts may be used with reference to the unlearned know-
ledge rather than the actions; but there is an approach to
a philosophic Malapropism in an indiscriminate use of the
Descartes' use of the term ' idea ' is wider than that of
Plato; he applies it to any kind of conscious experience.
(His use of ' thought ' (pense'e) is similar.) He even uses
'idea' for the nervous process accompanying sense-expe-
rience. It is only since Hume, who contrasts ' impressions '
and 'ideas/ that the latter much-abused term has been
restricted to a synonym for representative consciousness.
Cartesianism modified already in Descartes. *
Descartes then admitted that sense was a mode of mental
experience which the philosopher must account for as entering
into some cognitions, viz. Adventitious Ideas ; but he had to
assume other elements, viz. Innate Ideas, or Intuitions,
according as he referred to their primitive character, or to
the immediate certitude characterising them. Extension,
Number, are for him innate ideas. ' I am a thinking being ' is
a fundamental intuition ; so is ' Out of nothing nothing can
come', and ' A cause must contain at least as much reality
as its effect.' We have no sensation of extension, but we
interpret our sense-affections as coming from an extended
thing by means of our idea of extension. To the question,
' What guarantee have we that the idea has objective validity ? '
he answered, ' The existence of a veracious God, incapable
of deceiving us.' And to that of ' How is the mind cognisant
of these ideas ? ' he said, ' Mind is a being constantly con-
sciously thinking.' When pushed into a corner by the
XL] Elements of General Philosophy. 105
objection that, if such ideas are innate, children ought to be
more conscious of them than adults, he modified his position
by saying that the mind has predispositions to innate ideas.
His 'Innate' theory is really a protest against the Sensa-
tionalist position a protest with which as such I agree and
will not bear direct setting out here.
Locke, who really began the English philosophic move-
ment, thinks in relation to Descartes, though he generally
opposes him. The first book of his Essay is devoted to a
hostile criticism of the doctrine of Innate Ideas, all know-
ledge being traced from experience. Here then is a distinct
counter-assertion. Instead of the assertion that the nature
and community of knowledge are inexplicable save by way
of ideas implanted in the mind, and in all minds alike,
together with a theory as to the import of this innate knowing
with respect to all minds, a theory in short of the objectivity
of knowledge, we have the opposite view, that the mind
comes into the world devoid of ideas or of any original
means of interpreting experience, analogous in fact to a wax
tablet ready for the stylus that is to say, with a capacity for
receiving impressions and with nothing more. Knowledge
is that which arises in the mind as the result of the im-
pressions imparted by experience.
It was Locke who objected that if there were innate ideas
and principles (intuitions in the form of propositions), then,
according to Descartes' axiom, that mind does not exist to
the extent that it does not think, every one, but especially
children, would be always conscious of them ; whereas such
is not the case; indeed it would seem that none but
Cartesian philosophers were conscious of some of Descartes'
io6 Elements of General Philosophy. [LECT.
innate ideas ! Locke probably did not know, when he wrote,
how Descartes had (in a letter) modified his theory by
admitting predispositions. But Locke used the figure of the
tabula rasa l in a much more dogmatic sense than Aristotle.
The notion, on Locke's own line, has long been abandoned.
It must not, however, be supposed that Locke by the
metaphor meant to exclude ' natural faculties ' 2 or ' natural
tendencies imprinted in the minds of men ' 3 . It is merely his
strong way of saying that without actual experience (either
that which comes by way of the senses or that which he
calls ' Reflection ') there comes to pass nothing of what we
call knowledge. In this point of view he need not be
supposed to exclude anything that later inquirers contend
for under the head of Inherited Predisposition. He does
not assert that all tablets alike may be indifferently written
upon, or, on the other hand, deny that all human minds are
fitted to receive impressions in certain like ways. He may
however be charged, by his way of putting the case, with
throwing out of view this important element of a complete
theory of knowledge, viz. that there is a certain common
limit of knowing for the race and a certain personal range
for the individual, both predetermined in a manner that
admits of investigation (whether by Kant's way of analysis
or by the evolutionist historic procedure).
Locke's whole case against innate knowledge has reference
to the supposed ' universal consent ' respecting it in all men
and its express manifestation in the consciousness of each.
He seeks to show that no principle, speculative or practical,
that has ever been held innate, is as a matter of fact
expressly recognised and allowed for by all mankind, as
1 Essay, Bk. II, ch. i. a.
8 Ibid. 1, ii. i. 8 Ibid. I, iii. 3.
XL] Elements of General Philosophy. 107
it must be if innate. The uniformity of knowledge in
different men, so far as it exists, he explains by their being
exposed to the same experience, by their having the same
' natural faculties, 5 and by their communication with one
another 1 . Thus he does not wholly overlook the influence
of the social relation.
Whatever may be said of Locke's polemic against innate
knowledge however he fails to see what really was contended
for under that shibboleth (viz. that the fabric of knowledge,
for any mind, is never explicable from incidental experience
simply) it must be pronounced good and possible against
the doctrine as it had till then been maintained ; and this
is shown by the necessity laid upon Leibniz to shift ground
and maintain the position in quite a new way. Thus a real
advance in philosophy was rendered necessary.
Subsequent Mutual Convergence.
While Descartes maintained the extreme position of
Rationalism, and while we appear to find an extreme counter-
assertion of Sensationalism by Locke, what we discover
on tracing the course of subsequent philosophy is mainly in
the way of reconciliation and mutual approximation. The
Rationalists recognise sense as an indispensable factor of
what we call knowledge, the Sensationalists meanwhile pro-
gressively deepen and broaden their conception of what
enters into or is experience. The dogmatic assertion of
innate ideas died slain by Locke's Essay, or at least it only
lingered on here and there down to our own times. Leibniz,
who was most distinctly a Rationalist, finding knowledge in-
explicable from anything we can call external experience,
never asserted that the mind comes into the world with innate
1 See especially Essay I, iii. 22 ff.
io8 Elements of General Philosophy. [LECT.
ideas, but declared it has only predispositions, aptitudes, as
means of interpreting what comes to it by way of sense a
notion which shows a distinct advance towards an appreciation
of the other side. Ideas were only implicit in the infant mind
as a statue of Hercules might b,e said to be implicit in a
block of marble. Leibniz's theory of what really enters into
knowledge was based on his theory of substance. Descartes
had expressed the distinction between mind and matter as
between substances the whole character of which can be
expressed in thinking, and substances the whole character of
which can be expressed in extension. Leibniz gave up this
dualism, and allowed the existence of one substance only, the
reality of which lay neither in thinking nor in extension.
Trying to get a word deeper than either, he called the ground
of its reality active force, and the one substance a system of*
monads, or mental unitary beings. Not all have a self-con-
scious existence, and those which have do -not have it at every
moment of their existence. Mind appears at different grades
throughout the universe, from the Deity down to inanimate
objects appears, that is to say, as capable of all degrees of
subjective apprehension, from full self-conscious apperception
to semi- or sub- consciousness and down to unconsciousness.
Hence arose the theory of latent mental modifications,
springing originally from Locke's objection to Descartes'
definition of mind as something constantly self-conscious.
Leibniz and Locke.
In defining his own theory of knowledge, Leibniz took up
the formula of the Sensationalists : Nihil est in intellectu quod
non prius fueril in sensu, and gave it a turn noteworthy and
original by adding nisi ipse intellectus. 'Except the intellect
itself.' By this alone, he claimed, do we possess necessary
XL] Elements of General Philosophy. 109
knowledge, necessary truth. Some truths are merely truths of
fact ; others are necessary truths. We know sometimes that
' S is P,' but sometimes we know that ' S must be P.' And
he said, as against Locke, that, while we can account for
any mere assertion of fact from experience, to say that
anything 'must be' is not explicable from any kind of
experience. Locke, on the other hand, with never so blank
a tablet, found it necessary to assume beyond sense much
else, which he called faculties of analysing, compounding,
and the like. Experience for him was either external or
internal, i.e. either Sense or Reflexion, meaning by Sense
only the five passive senses, or modes of passive affection.
What then is Reflexion ? Consciousness of the fact of
perceiving, imagining, &c. To use modern phraseology
there is an order of objective experience and an order of
subjective experience : this expresses Locke's meaning.
Knowledge, he found, was altogether made up by experience
of Sense and Reflexion. But he has no definite idea how
these come together and combine. Compared with Leibniz's
profound psychological insight, Locke must be charged with
superficiality, with inability to apprehend the complexity of
the subject he sets himself to deal with.
Leibniz, however, by reason of his metaphysical start, is
in constant danger of diverting real psychological facts
into supports for questionable metaphysical positions. The
psychological fact that conscious life is composed of elements
multitudinous in number and of every degree of intensity
may be, should be, recognised quite apart from the meta-
physical hypothesis of monads.
Leibniz, while he does not deny that, not only truths of
fact, but even necessary truths come into conscious view
only upon the occasions supplied by sense, is disposed to
no Elements of General Philosophy. [LECT.
lay greater stress, for the explanation of knowledge, upon
that which the mind must be in itself in order to be affected
so. And as even the most occasional cognition may be
viewed in relation to the mind's inherent capacity, he con-
tends for innate knowledge in a sense which, if it departs
from the older view against which Locke contends, is not in
the least excluded by anything that Locke advances.
The Question advanced by a Step.
Locke thus appears after all as a masked Rationalist. He
merely opened up the Experientialist side of the question,
and it might well be said that Leibniz was only giving a
definite expression to Locke's implicit admission, when he
insisted on ' intellectus ipse ' as that which had not its origin
in sense. It was impossible that the question could remain
as Locke left it. Advance was necessary, or else a falling
back on Descartes.
When we come to Berkeley we shall see (infra, Lect. XVI)
that his Principles are directed against Locke's dogmatising
on matter. Still Locke it was who first began to transform
Philosophy into Theory of Knowledge. Philosophy with
Descartes was Theory of Being ; with Locke it was so only
secondarily. And more: his philosophy, if not psychologically
based, is at least penetrated through and through with the
psychological spirit. In Descartes' science we get some
good physics, but of any psychological understanding we
get next to no trace. Between his work on vision and that
of Berkeley there is all the difference between fancy and
science. What then enabled Berkeley in 1709 to do that
which Descartes of far greater scientific and philosophical
ability had been unable to do in 1637 ? I can assign no other
reason than the appearance in 1690 of Locke's Essay. For
XL] Elements of General Philosophy. in
whatever Spinoza's influence on the time may have been, he
had no influence upon Berkeley.
Locke's ideas of Sense are crude, but he compelled all
subsequent philosophy to admit that into the fabric of know-
ledge Sense enters as a distinct constituent, and that there is
no explanation of knowledge possible which does not take
account of Sense as a factor. What else there is in knowledge
beside Sense philosophers have since sought to make out.
The three chief verdicts are those of the Common Sense or
Scottish School, the Critical School, and the Associationist
School. These we will proceed to consider.
For LECTURE XII read:
Hamilton, Lectures on Metaphysics, XX and XXXVIII.
Hamilton, Works of Reid, with Dissertations by Hamilton
Note A, ' On the Philosophy of Common Sense.'
THE NATURE OF KNOWLEDGE. AFTER LOCKE.
THE Associationist doctrine has developed along two lines