The tendency of British philosophy has always been towards the
positivistic and practical rather than towards the mystical and
speculative. This trait we have already observed in the philosophy of
Hobbes and Bacon. It reappeared during the seventeenth and eighteenth
centuries in the critical and empirical philosophy of Locke, in the
natural philosophy of Newton, and in the theological doctrines of the
Deists. How the British moralists of the eighteenth century applied the
principle of empiricism to ethical problems, will be seen in the next
Life. John Locke was born in 1632 at Wrington, near Bristol. In
1646 he entered Westminster School and in 1652 he entered Christ
Church, Oxford. Here, although he found Scholasticism still in the
ascendency, he began to take an interest in Cartesian philosophy, and,
while it is certainly incorrect to regard Locke's empiricism as an
English branch of Cartesianism, there can be no doubt as to the
important influence of this early study of Descartes on the
philosophical career of Locke. On leaving Oxford Locke entered the
household of Lord Ashley, afterwards Earl of Shaftesbury, as secretary,
tutor, and physician. After the downfall and death of his patron Locke
took up his residence in Holland (1683). There he remained until 1689,
when he returned to England in the suite of William of Orange. He died
at Oates, in Essex, in the year 1704.
Sources. Locke's works, which were first published in nine
volumes (London, 1714), include the Essay concerning Human
Understanding, Thoughts concerning Education, Two Treatises on
Government, The Reasonableness of Christianity as delivered in
Scripture, and other treatises. The best edition of the
Essay is that of Alexander Campbell Fraser (2 vols., Clarendon
Press, 1894). Manuals to be consulted: Fraser's Locke
(Blackwood's Philosophical Classics, Edinburgh and Philadelphia, 1890)
and Marion's J. Locke, sa vie et son oeuvre (Paris, 1893). 
 Consult also article on Locke in Encyc. Brit., Dewey's
Leibniz's New Essays (Chicago, 1888), and Green's
Introduction in edition of Hume's Works.
Starting Point. All Locke's Philosophy centers in his theory of
cognition, and his theory of cognition is based on the principle which
may be enunciated negatively by saying that there are no innate ideas,
or affirmatively by saying that all knowledge comes from experience.
There are no innate ideas. The first book of the Essay is
devoted to proving that "there are no innate principles in the mind."
Locke observes that the universal acceptance of certain principles is
taken as a proof of their innateness. He then proceeds to show that
facts do not sustain the contention that the principles in question,
or, indeed, any principles, are universally accepted. Children and
uneducated persons are ignorant of the principles of identity and
contradiction; the existence of atheism and polytheism demonstrates
that the idea of God is not present in the minds of all men from the
beginning and the well-known diversity of the moral ideals of different
races and nations proves that the elementary principles of morality are
not universally accepted. He further adduces positive evidence against
the innateness of these principles, arguing that the ideas which
compose them are abstract, and therefore do not appear in consciousness
until a comparatively late period in the mental development of the
individual. Here, as well as elsewhere Locke assumes that to be in
the mind and to be known are one and the same.
The mind, therefore, is in the beginning a blank sheet, or, to use the
Aristotelian phrase, a tabula rasa. It remains to inquire how
our ideas are acquired.
Analysis of Experience. The second book of the Essay is
devoted to the task of showing how our ideas originate by experience
Experience, Locke teaches, is twofold: sensation, or the
perception of external phenomena by means of the senses, and
reflection or the perception of the internal phenomena, that
is, of the activity of the understanding itself. From these two
sources arise all our ideas. Now, our ideas are either
simple or complex. Simple ideas are those which are
"furnished" to the mind by sensation and reflection, the understanding
itself remaining perfectly passive; complex ideas are those which the
understanding "makes" by "repeating, comparing, and combining" simple
 Essay, II, 2.
(a) Simple ideas. Simple ideas are divided into four classes:
(1) those which come into the mind by one sense only; (2) those which
convey themselves into the mind by more senses than one; (3) those
which are had from reflection only; (4) those which are suggested to
the mind by all the ways of sensation and reflection. To the first
class belong not only the ideas of color, taste, etc., but also that of
solidity, or impenetrability. It is this quality, and not, as Descartes
taught, extension, that is the primary attribute of body. To the second
class belong our ideas of motion, space, etc. As examples of the third
class Locke instances the ideas of thought and will, while to the last
class he assigns our ideas of pleasure and power. 
 Op. cit., II, 3-6.
With regard to the validity of simple ideas, Locke adopts Boyle's
division of the qualities of bodies into primary and secondary.
Secondary qualities, such as colors, tastes, etc., do not really exist
in bodies; real existence can be attributed only to primary qualities,
such as bulk, figure, motion, etc., which have the power to produce in
us the simple ideas of secondary qualities. Here Locke fails to
distinguish between the psychic and the physical aspect of secondary
qualities, and from the undeniable fact that the quality of color, for
example in its psychic aspect, exists in the mind alone, concludes
that, in no true sense of the word, can color be said to exist outside
the mind. 
 Cf.op. cit., II, 8.
(b) Complex ideas. In the twelfth chapter of the second book of the
Essay, Locke divides complex ideas into three classes ideas of
modes, ideas of substances, and ideas of relations.
(alpha) Modes are defined as "complex ideas which, however
compounded, contain not in them the supposition of subsisting by
themselves, but are considered as dependencies on or affections of
substances." Simple modes are combinations of the same simple
idea: thus, distance, surface, figure are modifications and
combinations of the simple idea of space; duration, time, and eternity
are simple modes of the idea of duration, while memory, reasoning, and
judging are simple modes of the idea of thinking. Mixed modes
are combinations of different kinds of simple ideas. For example, the
idea of sacrilege or of murder is made up of the simple ideas of
action, circumstance, motive, etc. 
 Op. cit., II, 12-13
(beta) Substance. Not being able to conceive how simple ideas
can subsist by themselves, we form a complex idea of substance
as the substratum which "upholds" them. Substance, then, is not
primarily conceived as that which is capable of subsisting by itself,
but rather as that which upholds or supports the qualities of
things.  Thus, the substance of the rose is the complex idea of that
which upholds or supports the simple ideas, color, fragrance, softness,
 Op. cit., II, 23.
Whatever Locke may have meant when he said that our idea of substance
is obscure, his First Letter to the Bishop of Worcester removes all
doubt as to his belief in the real existence of substance.
Indeed, the letter explicitly distinguishes between our knowledge that
substance is and our knowledge of what it is.
Substance is threefold, -- bodily, spiritual, and divine.
We have as clear an idea of spiritual substance as we have of bodily
substance; for thought is as easily known as extension, and will is as
easily known as impulsion or force. And the idea of divine substance
offers no special difficulty; for it is merely the complex idea made up
of our ideas of existence, power, knowledge, etc., to which is added
the idea of infinite. The idea of infinite is obtained by the addition
of finite to finite.
(gamma) Relations. A relation arises "when the mind so
considers one thing that it does, as it were, bring it to, and set it
by another, and carries its view from the one to the other." 
Relations are innumerable. Locke undertakes to discuss merely the
principal relations, as, for example, causality and identity.
 Op. cit., II, 25.
Although Locke's analysis of the relation of causality seems
unimportant when compared with Hume's more thorough analysis of the
causal axiom, nevertheless the mere fact of reducing causality to a
relation rather than to the category of substance or action is a
revolution in philosophy. Locke defines a cause as that which
produces, and an effect as that which is produced. He does not,
therefore, reduce causality to mere sequence; he teaches that there are
real causes as there are real substances.
The relation of identity arises "when, considering anything as
existing at any determined time and place, we compare it with itself
existing at another time."  Locke teaches that the principle of
individuation is existence itself; but as the existence of living
bodies is not the same as that of mere masses of matter, the identity
of living bodies is the permanence of organization, while the identity
of a mere mass of matter is the identity of its aggregated particles
(atoms). Personal identity (the identity of man) is the
continuity of consciousness. Locke apparently fails to distinguish
between the psychological and the ontological aspect of the problem of
personality, -- between the question, How is personal identity known?
and the question, How is personal identity constituted?
 Op. cit., II, 27.
Philosophy of Language. In the third book of the Essay
Locke treats of the philosophy of language. Words do not, as is
generally supposed, signify things. Neither do they, in their primary
or immediate signification, stand for ideas common to all men, but
merely for the ideas in the mind of him who uses them. Now, it is
impossible that every particular thing should have its own name;
indeed, "the greatest part of words are
general terms" used to express general ideas. The generality and
universality of names and ideas are, therefore, mere creatures and
inventions of the understanding and belong not to the existence of
things (nominalism). Locke considers, in particular, the relation of
our universal ideas to the essences of things, pointing out the
distinction between nominal and real essences. Real
essence is "the very being of anything, whereby it is what it is";
nominal essence is "the abstract idea which the general name stands
for."  Thus, the real essence of gold is that which makes gold to be
what it is (the "substantial form" of Aristotle and the schoolmen),
while the nominal essence is the complex idea of the color, weight,
malleability, etc., of gold. Now we can and do know the nominal
essences of material substances, but, as to real essences, although we
know that they exist we cannot know what they are; for we have no means
of judging whether the real essence which constitutes the "insensible"
parts of gold is like the nominal essence, which is the complex idea
including yellow, malleable, etc. We know the surface qualities of
things, but we are no more competent to judge what the real essence is
than the countryman who sees the exterior of the clock at Strasburg and
hears it strike is competent to judge of the mechanism with which the
clock is provided.  Locke grants that the qualities which constitute
the nominal essence are produced by the real essence, but apparently
overlooks the principle that, by virtue of the similarity of effect to
cause, we may proceed from the knowledge of the effect to the knowledge
of the cause.
 Op. cit., III, 3
 Op. cit., III, 6.
Theory of Knowledge. The fourth book of the Essay is
devoted to the study of the extent and validity of knowledge. Knowledge
is defined  as "the perception of the connexion of and agreement or
disagreement and repugnance of our ideas." It is of three kinds, --
intuitive, demonstrative, and sensitive. Intuitive
knowledge is "the perception of the agreement or
disagreement of two ideas immediately by themselves without the
intervention of any other." It is by means of this knowledge that we
perceive that three equals one and two, and it is on the same kind of
knowledge that the certainty and evidence of all our knowledge
depend. Demonstrative knowledge is the perception of the
agreement or disagreement of two ideas by the intervention of other
ideas, as, for example, the perception of the agreement of the sum of
the three angles of a triangle and two right angles. Sensitive
knowledge is "the perception of the particular existence of finite
beings without us."
 Op. cit., IV, 2.
 Op. cit., IV, 2.
Intuitive knowledge is the basis of all certitude; demonstrative
knowledge is less clear than intuitive knowledge, and, therefore,
inferior to it; but demonstrative knowledge is, in turn, superior to
sensitive knowledge. Yet, while rating sensitive knowledge so low, and
describing it as "going beyond bare probability," Locke does not deny
the validity of sensitive knowledge when it testifies to the existence
of external things.
Our knowledge of our own existence is intuitive; our knowledge of the
existence of God is demonstrative; and our knowledge of other things is
 Op. cit., IV, 9.
Moral and Political Doctrines.  Locke's ethical and political
doctrines bear the general character of his theoretical speculations
-- they aim at being empirical. There are four determinants of
moral good: reason, the will of God, the general good, and
self-interest. To each of these in turn Locke appeals without
determining the relations of one to the others.  In his treatises on
political government he combats the principles of state
absolutism, maintaining that natural rights were in no way
abrogated by the transition of primitive man from the state of nature
to the conditions of political life. He defends the
constitutional theory, advocates the supremacy of the legislative
power, and teaches that, in a conflict between the legislative and the
executive powers, the will of the nation is supreme, because, in such
an event, sovereign authority reverts to the source whence it is
derived, namely the people. Locke is commonly regarded as the founder
of that philosophy of civil government which inspired the great modern
movements towards popular representation, the extension of the rights
of subjects, and the restriction of monarchical privileges.
 Consult Curtis, An Outline of Locke's Ethical Philosophy
 Cf. Falckenberg, Geschichte der neueren Philosophie,
p. 244; English trans. p. 178.
Historical Position. Locke is commonly styled the successor of
Bacon and Hobbes, although it is sometimes denied that he was
influenced directly by the writings of either of these philosophers.
The man, however, who exercised the greatest influence on Locke was
Descartes.  This influence was indirect as well as direct. Thus,
Locke begins his Essay by denying the innateness of ideas, -- a
distinctively Cartesian doctrine; and throughout his inquiry into the
nature and value of knowledge he is constantly denying what Descartes
affirmed, and affirming what Descartes denied. And yet the cardinal
idea of Cartesianism, namely the antithesis between mind and matter,
appears as a tacit assumption in Locke's inquiry, and underlies
everything that Locke wrote concerning human knowledge.
 Cf. Thilly, Leibnizens Streit gegen Locke
(Heidelberg, 1892), pp. 5-32.
Locke's original contribution to philosophy may be described by saying
that he introduced the critical spirit. For him the paramount problem
was to determine the nature, value, and extent of human knowledge, and
the method which he employed was the empirical rather than the
rational, or deductive. He applied to the study of the mind the method
which Bacon advocated as best suited to the study of nature. The result
which he reached was the establishment of an empiricism which is, in
ultimate analysis, a system of sensism. His chief defect is
superficiality, -- a defect common to his school. He stopped where
the real problems of philosophy begin, and although, as
the subsequent development of empiricism in France has shown, his
premises led inevitably to materialism, he himself maintained, with
characteristic inconsistency, the spirituality of the human soul and
the existence of purely spiritual substances.
Sir Isaac Newton (1642-1727) is the most important representative of
the scientific phase of the English empiricism of the seventeenth
century. His chief works are Philosophiae Naturalis Principia
Mathematica (1687) and Opticks (1704). The philosophical
importance of his discovery of the law and theory of universal
gravitation lies in this, -- that it established the fact that the
physical laws which hold good on the surface of the earth are valid
throughout the universe, as far as we can know anything about it.