Plato's doctrine of ideas has attained an imaginary clearness and
definiteness which is not to be found in his own writings. The popular
account of them is partly derived from one or two passages in his
Dialogues interpreted without regard to their poetical environment. It
is due also to the misunderstanding of him by the Aristotelian school;
and the erroneous notion has been further narrowed and has become fixed
by the realism of the schoolmen. This popular view of the Platonic ideas
may be summed up in some such formula as the following: 'Truth consists
not in particulars, but in universals, which have a place in the mind of
God, or in some far-off heaven. These were revealed to men in a former
state of existence, and are recovered by reminiscence (anamnesis) or
association from sensible things. The sensible things are not
realities, but shadows only, in relation to the truth.' These unmeaning
propositions are hardly suspected to be a caricature of a great theory
of knowledge, which Plato in various ways and under many figures of
speech is seeking to unfold. Poetry has been converted into dogma; and
it is not remarked that the Platonic ideas are to be found only in about
a third of Plato's writings and are not confined to him. The forms which
they assume are numerous, and if taken literally, inconsistent with one
another. At one time we are in the clouds of mythology, at another among
the abstractions of mathematics or metaphysics; we pass imperceptibly
from one to the other. Reason and fancy are mingled in the same
passage. The ideas are sometimes described as many, coextensive with
the universals of sense and also with the first principles of ethics; or
again they are absorbed into the single idea of good, and subordinated
to it. They are not more certain than facts, but they are equally
certain (Phaedo). They are both personal and impersonal. They are
abstract terms: they are also the causes of things; and they are even
transformed into the demons or spirits by whose help God made the world.
And the idea of good (Republic) may without violence be converted into
the Supreme Being, who 'because He was good' created all things (Tim.).
It would be a mistake to try and reconcile these differing modes of
thought. They are not to be regarded seriously as having a distinct
meaning. They are parables, prophecies, myths, symbols, revelations,
aspirations after an unknown world. They derive their origin from a deep
religious and contemplative feeling, and also from an observation of
curious mental phenomena. They gather up the elements of the previous
philosophies, which they put together in a new form. Their great
diversity shows the tentative character of early endeavours to think.
They have not yet settled down into a single system. Plato uses them,
though he also criticises them; he acknowledges that both he and others
are always talking about them, especially about the Idea of Good; and
that they are not peculiar to himself (Phaedo; Republic; Soph.). But in
his later writings he seems to have laid aside the old forms of them.
As he proceeds he makes for himself new modes of expression more akin to
the Aristotelian logic.
Yet amid all these varieties and incongruities, there is a common
meaning or spirit which pervades his writings, both those in which he
treats of the ideas and those in which he is silent about them. This is
the spirit of idealism, which in the history of philosophy has had many
names and taken many forms, and has in a measure influenced those
who seemed to be most averse to it. It has often been charged with
inconsistency and fancifulness, and yet has had an elevating effect on
human nature, and has exercised a wonderful charm and interest over
a few spirits who have been lost in the thought of it. It has been
banished again and again, but has always returned. It has attempted to
leave the earth and soar heavenwards, but soon has found that only
in experience could any solid foundation of knowledge be laid. It has
degenerated into pantheism, but has again emerged. No other knowledge
has given an equal stimulus to the mind. It is the science of sciences,
which are also ideas, and under either aspect require to be defined.
They can only be thought of in due proportion when conceived in relation
to one another. They are the glasses through which the kingdoms of
science are seen, but at a distance. All the greatest minds, except when
living in an age of reaction against them, have unconsciously fallen
under their power.
The account of the Platonic ideas in the Meno is the simplest and
clearest, and we shall best illustrate their nature by giving this first
and then comparing the manner in which they are described elsewhere,
e.g. in the Phaedrus, Phaedo, Republic; to which may be added the
criticism of them in the Parmenides, the personal form which is
attributed to them in the Timaeus, the logical character which they
assume in the Sophist and Philebus, and the allusion to them in the
Laws. In the Cratylus they dawn upon him with the freshness of a
newly-discovered thought.
The Meno goes back to a former state of existence, in which men did and
suffered good and evil, and received the reward or punishment of them
until their sin was purged away and they were allowed to return to
earth. This is a tradition of the olden time, to which priests and poets
bear witness. The souls of men returning to earth bring back a latent
memory of ideas, which were known to them in a former state. The
recollection is awakened into life and consciousness by the sight of the
things which resemble them on earth. The soul evidently possesses such
innate ideas before she has had time to acquire them. This is proved by
an experiment tried on one of Meno's slaves, from whom Socrates elicits
truths of arithmetic and geometry, which he had never learned in this
world. He must therefore have brought them with him from another.
The notion of a previous state of existence is found in the verses
of Empedocles and in the fragments of Heracleitus. It was the natural
answer to two questions, 'Whence came the soul? What is the origin of
evil?' and prevailed far and wide in the east. It found its way into
Hellas probably through the medium of Orphic and Pythagorean rites and
mysteries. It was easier to think of a former than of a future life,
because such a life has really existed for the race though not for the
individual, and all men come into the world, if not 'trailing clouds of
glory,' at any rate able to enter into the inheritance of the past. In
the Phaedrus, as well as in the Meno, it is this former rather than a
future life on which Plato is disposed to dwell. There the Gods, and men
following in their train, go forth to contemplate the heavens, and are
borne round in the revolutions of them. There they see the divine forms
of justice, temperance, and the like, in their unchangeable beauty, but
not without an effort more than human. The soul of man is likened to
a charioteer and two steeds, one mortal, the other immortal. The
charioteer and the mortal steed are in fierce conflict; at length the
animal principle is finally overpowered, though not extinguished, by the
combined energies of the passionate and rational elements. This is one
of those passages in Plato which, partaking both of a philosophical
and poetical character, is necessarily indistinct and inconsistent. The
magnificent figure under which the nature of the soul is described has
not much to do with the popular doctrine of the ideas. Yet there is one
little trait in the description which shows that they are present to
Plato's mind, namely, the remark that the soul, which had seen truths
in the form of the universal, cannot again return to the nature of an
animal.
In the Phaedo, as in the Meno, the origin of ideas is sought for in a
previous state of existence. There was no time when they could have been
acquired in this life, and therefore they must have been recovered from
another. The process of recovery is no other than the ordinary law of
association, by which in daily life the sight of one thing or person
recalls another to our minds, and by which in scientific enquiry from
any part of knowledge we may be led on to infer the whole. It is also
argued that ideas, or rather ideals, must be derived from a previous
state of existence because they are more perfect than the sensible forms
of them which are given by experience. But in the Phaedo the doctrine
of ideas is subordinate to the proof of the immortality of the soul.
'If the soul existed in a previous state, then it will exist in a future
state, for a law of alternation pervades all things.' And, 'If the ideas
exist, then the soul exists; if not, not.' It is to be observed, both
in the Meno and the Phaedo, that Socrates expresses himself with
diffidence. He speaks in the Phaedo of the words with which he has
comforted himself and his friends, and will not be too confident that
the description which he has given of the soul and her mansions is
exactly true, but he 'ventures to think that something of the kind is
true.' And in the Meno, after dwelling upon the immortality of the
soul, he adds, 'Of some things which I have said I am not altogether
confident' (compare Apology; Gorgias). From this class of uncertainties
he exempts the difference between truth and appearance, of which he is
absolutely convinced.
In the Republic the ideas are spoken of in two ways, which though not
contradictory are different. In the tenth book they are represented as
the genera or general ideas under which individuals having a common name
are contained. For example, there is the bed which the carpenter makes,
the picture of the bed which is drawn by the painter, the bed existing
in nature of which God is the author. Of the latter all visible beds
are only the shadows or reflections. This and similar illustrations or
explanations are put forth, not for their own sake, or as an exposition
of Plato's theory of ideas, but with a view of showing that poetry and
the mimetic arts are concerned with an inferior part of the soul and a
lower kind of knowledge. On the other hand, in the 6th and 7th books
of the Republic we reach the highest and most perfect conception, which
Plato is able to attain, of the nature of knowledge. The ideas are now
finally seen to be one as well as many, causes as well as ideas, and to
have a unity which is the idea of good and the cause of all the rest.
They seem, however, to have lost their first aspect of universals under
which individuals are contained, and to have been converted into forms
of another kind, which are inconsistently regarded from the one side as
images or ideals of justice, temperance, holiness and the like; from the
other as hypotheses, or mathematical truths or principles.
In the Timaeus, which in the series of Plato's works immediately follows
the Republic, though probably written some time afterwards, no mention
occurs of the doctrine of ideas. Geometrical forms and arithmetical
ratios furnish the laws according to which the world is created. But
though the conception of the ideas as genera or species is forgotten or
laid aside, the distinction of the visible and intellectual is as
firmly maintained as ever. The IDEA of good likewise disappears and is
superseded by the conception of a personal God, who works according to
a final cause or principle of goodness which he himself is. No doubt is
expressed by Plato, either in the Timaeus or in any other dialogue, of
the truths which he conceives to be the first and highest. It is not the
existence of God or the idea of good which he approaches in a tentative
or hesitating manner, but the investigations of physiology. These he
regards, not seriously, as a part of philosophy, but as an innocent
recreation (Tim.).
Passing on to the Parmenides, we find in that dialogue not an exposition
or defence of the doctrine of ideas, but an assault upon them, which is
put into the mouth of the veteran Parmenides, and might be ascribed to
Aristotle himself, or to one of his disciples. The doctrine which is
assailed takes two or three forms, but fails in any of them to escape
the dialectical difficulties which are urged against it. It is admitted
that there are ideas of all things, but the manner in which individuals
partake of them, whether of the whole or of the part, and in which
they become like them, or how ideas can be either within or without
the sphere of human knowledge, or how the human and divine can have any
relation to each other, is held to be incapable of explanation. And
yet, if there are no universal ideas, what becomes of philosophy?
(Parmenides.) In the Sophist the theory of ideas is spoken of as a
doctrine held not by Plato, but by another sect of philosophers, called
'the Friends of Ideas,' probably the Megarians, who were very distinct
from him, if not opposed to him (Sophist). Nor in what may be termed
Plato's abridgement of the history of philosophy (Soph.), is any mention
made such as we find in the first book of Aristotle's Metaphysics,
of the derivation of such a theory or of any part of it from the
Pythagoreans, the Eleatics, the Heracleiteans, or even from Socrates. In
the Philebus, probably one of the latest of the Platonic Dialogues,
the conception of a personal or semi-personal deity expressed under the
figure of mind, the king of all, who is also the cause, is retained. The
one and many of the Phaedrus and Theaetetus is still working in the mind
of Plato, and the correlation of ideas, not of 'all with all,' but of
'some with some,' is asserted and explained. But they are spoken of in
a different manner, and are not supposed to be recovered from a former
state of existence. The metaphysical conception of truth passes into a
psychological one, which is continued in the Laws, and is the final
form of the Platonic philosophy, so far as can be gathered from his own
writings (see especially Laws). In the Laws he harps once more on the
old string, and returns to general notions:--these he acknowledges to
be many, and yet he insists that they are also one. The guardian must be
made to recognize the truth, for which he has contended long ago in the
Protagoras, that the virtues are four, but they are also in some sense
one (Laws; compare Protagoras).
So various, and if regarded on the surface only, inconsistent, are the
statements of Plato respecting the doctrine of ideas. If we attempted to
harmonize or to combine them, we should make out of them, not a system,
but the caricature of a system. They are the ever-varying expression
of Plato's Idealism. The terms used in them are in their substance and
general meaning the same, although they seem to be different. They
pass from the subject to the object, from earth (diesseits) to
heaven (jenseits) without regard to the gulf which later theology and
philosophy have made between them. They are also intended to supplement
or explain each other. They relate to a subject of which Plato himself
would have said that 'he was not confident of the precise form of his
own statements, but was strong in the belief that something of the kind
was true.' It is the spirit, not the letter, in which they agree--the
spirit which places the divine above the human, the spiritual above the
material, the one above the many, the mind before the body.
The stream of ancient philosophy in the Alexandrian and Roman times
widens into a lake or sea, and then disappears underground to reappear
after many ages in a distant land. It begins to flow again under new
conditions, at first confined between high and narrow banks, but finally
spreading over the continent of Europe. It is and is not the same with
ancient philosophy. There is a great deal in modern philosophy which is
inspired by ancient. There is much in ancient philosophy which was 'born
out of due time; and before men were capable of understanding it. To the
fathers of modern philosophy, their own thoughts appeared to be new
and original, but they carried with them an echo or shadow of the past,
coming back by recollection from an elder world. Of this the enquirers
of the seventeenth century, who to themselves appeared to be working out
independently the enquiry into all truth, were unconscious. They stood
in a new relation to theology and natural philosophy, and for a time
maintained towards both an attitude of reserve and separation. Yet the
similarities between modern and ancient thought are greater far than the
differences. All philosophy, even that part of it which is said to be
based upon experience, is really ideal; and ideas are not only derived
from facts, but they are also prior to them and extend far beyond them,
just as the mind is prior to the senses.
Early Greek speculation culminates in the ideas of Plato, or rather in
the single idea of good. His followers, and perhaps he himself, having
arrived at this elevation, instead of going forwards went backwards from
philosophy to psychology, from ideas to numbers. But what we perceive to
be the real meaning of them, an explanation of the nature and origin
of knowledge, will always continue to be one of the first problems of
philosophy.
Plato also left behind him a most potent instrument, the forms of
logic--arms ready for use, but not yet taken out of their armoury. They
were the late birth of the early Greek philosophy, and were the only
part of it which has had an uninterrupted hold on the mind of Europe.
Philosophies come and go; but the detection of fallacies, the framing
of definitions, the invention of methods still continue to be the main
elements of the reasoning process.
Modern philosophy, like ancient, begins with very simple conceptions.
It is almost wholly a reflection on self. It might be described as
a quickening into life of old words and notions latent in the
semi-barbarous Latin, and putting a new meaning into them. Unlike
ancient philosophy, it has been unaffected by impressions derived from
outward nature: it arose within the limits of the mind itself. From the
time of Descartes to Hume and Kant it has had little or nothing to do
with facts of science. On the other hand, the ancient and mediaeval
logic retained a continuous influence over it, and a form like that
of mathematics was easily impressed upon it; the principle of ancient
philosophy which is most apparent in it is scepticism; we must doubt
nearly every traditional or received notion, that we may hold fast one
or two. The being of God in a personal or impersonal form was a mental
necessity to the first thinkers of modern times: from this alone all
other ideas could be deduced. There had been an obscure presentiment of
'cognito, ergo sum' more than 2000 years previously. The Eleatic notion
that being and thought were the same was revived in a new form by
Descartes. But now it gave birth to consciousness and self-reflection:
it awakened the 'ego' in human nature. The mind naked and abstract has
no other certainty but the conviction of its own existence. 'I think,
therefore I am;' and this thought is God thinking in me, who has also
communicated to the reason of man his own attributes of thought and
extension--these are truly imparted to him because God is true (compare
Republic). It has been often remarked that Descartes, having begun by
dismissing all presuppositions, introduces several: he passes almost
at once from scepticism to dogmatism. It is more important for the
illustration of Plato to observe that he, like Plato, insists that God
is true and incapable of deception (Republic)--that he proceeds from
general ideas, that many elements of mathematics may be found in him. A
certain influence of mathematics both on the form and substance of their
philosophy is discernible in both of them. After making the greatest
opposition between thought and extension, Descartes, like Plato,
supposes them to be reunited for a time, not in their own nature but by
a special divine act (compare Phaedrus), and he also supposes all
the parts of the human body to meet in the pineal gland, that alone
affording a principle of unity in the material frame of man. It is
characteristic of the first period of modern philosophy, that having
begun (like the Presocratics) with a few general notions, Descartes
first falls absolutely under their influence, and then quickly discards
them. At the same time he is less able to observe facts, because they
are too much magnified by the glasses through which they are seen.
The common logic says 'the greater the extension, the less the
comprehension,' and we may put the same thought in another way and say
of abstract or general ideas, that the greater the abstraction of them,
the less are they capable of being applied to particular and concrete
natures.
Not very different from Descartes in his relation to ancient philosophy
is his successor Spinoza, who lived in the following generation. The
system of Spinoza is less personal and also less dualistic than that
of Descartes. In this respect the difference between them is like that
between Xenophanes and Parmenides. The teaching of Spinoza might be
described generally as the Jewish religion reduced to an abstraction
and taking the form of the Eleatic philosophy. Like Parmenides, he is
overpowered and intoxicated with the idea of Being or God. The greatness
of both philosophies consists in the immensity of a thought which
excludes all other thoughts; their weakness is the necessary separation
of this thought from actual existence and from practical life. In
neither of them is there any clear opposition between the inward and
outward world. The substance of Spinoza has two attributes, which alone
are cognizable by man, thought and extension; these are in extreme
opposition to one another, and also in inseparable identity. They may be
regarded as the two aspects or expressions under which God or substance
is unfolded to man. Here a step is made beyond the limits of the Eleatic
philosophy. The famous theorem of Spinoza, 'Omnis determinatio est
negatio,' is already contained in the 'negation is relation' of Plato's
Sophist. The grand description of the philosopher in Republic VI, as the
spectator of all time and all existence, may be paralleled with
another famous expression of Spinoza, 'Contemplatio rerum sub specie
eternitatis.' According to Spinoza finite objects are unreal, for they
are conditioned by what is alien to them, and by one another. Human
beings are included in the number of them. Hence there is no reality
in human action and no place for right and wrong. Individuality is
accident. The boasted freedom of the will is only a consciousness of
necessity. Truth, he says, is the direction of the reason towards the
infinite, in which all things repose; and herein lies the secret of
man's well-being. In the exaltation of the reason or intellect, in the
denial of the voluntariness of evil (Timaeus; Laws) Spinoza approaches
nearer to Plato than in his conception of an infinite substance. As
Socrates said that virtue is knowledge, so Spinoza would have maintained
that knowledge alone is good, and what contributes to knowledge useful.
Both are equally far from any real experience or observation of nature.
And the same difficulty is found in both when we seek to apply their
ideas to life and practice. There is a gulf fixed between the infinite
substance and finite objects or individuals of Spinoza, just as there is
between the ideas of Plato and the world of sense.
Removed from Spinoza by less than a generation is the philosopher
Leibnitz, who after deepening and intensifying the opposition between
mind and matter, reunites them by his preconcerted harmony (compare
again Phaedrus). To him all the particles of matter are living beings
which reflect on one another, and in the least of them the whole is
contained. Here we catch a reminiscence both of the omoiomere, or
similar particles of Anaxagoras, and of the world-animal of the Timaeus.
In Bacon and Locke we have another development in which the mind of
man is supposed to receive knowledge by a new method and to work by
observation and experience. But we may remark that it is the idea
of experience, rather than experience itself, with which the mind is
filled. It is a symbol of knowledge rather than the reality which is
vouchsafed to us. The Organon of Bacon is not much nearer to actual
facts than the Organon of Aristotle or the Platonic idea of good. Many
of the old rags and ribbons which defaced the garment of philosophy have
been stripped off, but some of them still adhere. A crude conception of
the ideas of Plato survives in the 'forms' of Bacon. And on the other
hand, there are many passages of Plato in which the importance of the
investigation of facts is as much insisted upon as by Bacon. Both are
almost equally superior to the illusions of language, and are constantly
crying out against them, as against other idols.
Locke cannot be truly regarded as the author of sensationalism any more
than of idealism. His system is based upon experience, but with him
experience includes reflection as well as sense. His analysis and
construction of ideas has no foundation in fact; it is only the
dialectic of the mind 'talking to herself.' The philosophy of Berkeley
is but the transposition of two words. For objects of sense he would
substitute sensations. He imagines himself to have changed the relation
of the human mind towards God and nature; they remain the same as
before, though he has drawn the imaginary line by which they are divided
at a different point. He has annihilated the outward world, but it
instantly reappears governed by the same laws and described under the
same names.
A like remark applies to David Hume, of whose philosophy the central
principle is the denial of the relation of cause and effect. He would
deprive men of a familiar term which they can ill afford to lose; but
he seems not to have observed that this alteration is merely verbal and
does not in any degree affect the nature of things. Still less did he
remark that he was arguing from the necessary imperfection of language
against the most certain facts. And here, again, we may find a parallel
with the ancients. He goes beyond facts in his scepticism, as they did
in their idealism. Like the ancient Sophists, he relegates the more
important principles of ethics to custom and probability. But crude and
unmeaning as this philosophy is, it exercised a great influence on his
successors, not unlike that which Locke exercised upon Berkeley and
Berkeley upon Hume himself. All three were both sceptical and ideal in
almost equal degrees. Neither they nor their predecessors had any true
conception of language or of the history of philosophy. Hume's
paradox has been forgotten by the world, and did not any more than the
scepticism of the ancients require to be seriously refuted. Like some
other philosophical paradoxes, it would have been better left to die
out. It certainly could not be refuted by a philosophy such as Kant's,
in which, no less than in the previously mentioned systems, the history
of the human mind and the nature of language are almost wholly ignored,
and the certainty of objective knowledge is transferred to the subject;
while absolute truth is reduced to a figment, more abstract and narrow
than Plato's ideas, of 'thing in itself,' to which, if we reason
strictly, no predicate can be applied.
The question which Plato has raised respecting the origin and nature of
ideas belongs to the infancy of philosophy; in modern times it would no
longer be asked. Their origin is only their history, so far as we know
it; there can be no other. We may trace them in language, in philosophy,
in mythology, in poetry, but we cannot argue a priori about them. We may
attempt to shake them off, but they are always returning, and in every
sphere of science and human action are tending to go beyond facts. They
are thought to be innate, because they have been familiar to us all our
lives, and we can no longer dismiss them from our mind. Many of them
express relations of terms to which nothing exactly or nothing at all in
rerum natura corresponds. We are not such free agents in the use of
them as we sometimes imagine. Fixed ideas have taken the most complete
possession of some thinkers who have been most determined to renounce
them, and have been vehemently affirmed when they could be least
explained and were incapable of proof. The world has often been led away
by a word to which no distinct meaning could be attached. Abstractions
such as 'authority,' 'equality,' 'utility,' 'liberty,' 'pleasure,'
'experience,' 'consciousness,' 'chance,' 'substance,' 'matter,' 'atom,'
and a heap of other metaphysical and theological terms, are the source
of quite as much error and illusion and have as little relation
to actual facts as the ideas of Plato. Few students of theology or
philosophy have sufficiently reflected how quickly the bloom of a
philosophy passes away; or how hard it is for one age to understand the
writings of another; or how nice a judgment is required of those who are
seeking to express the philosophy of one age in the terms of another.
The 'eternal truths' of which metaphysicians speak have hardly ever
lasted more than a generation. In our own day schools or systems of
philosophy which have once been famous have died before the founders of
them. We are still, as in Plato's age, groping about for a new method
more comprehensive than any of those which now prevail; and also more
permanent. And we seem to see at a distance the promise of such a
method, which can hardly be any other than the method of idealized
experience, having roots which strike far down into the history of
philosophy. It is a method which does not divorce the present from the
past, or the part from the whole, or the abstract from the concrete,
or theory from fact, or the divine from the human, or one science
from another, but labours to connect them. Along such a road we have
proceeded a few steps, sufficient, perhaps, to make us reflect on the
want of method which prevails in our own day. In another age, all the
branches of knowledge, whether relating to God or man or nature, will
become the knowledge of 'the revelation of a single science' (Symp.),
and all things, like the stars in heaven, will shed their light upon one
another.