Dr. Katherine Heenan
English 472
Spring 2007
Notes: John Locke, 1632-1704, Essay on Human Understanding
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a British philosopher
Oxford academic and medical researcher
his association with Anthony Ashley Cooper (later the First Earl of Shaftesbury) led him to
become
o a government official charged with collecting information about trade and colonies,
o An economic writer, opposition political activist, and
o finally a revolutionary whose cause ultimately triumphed in the Glorious Revolution of
1688.
Much of his work is characterized by opposition to authoritarianism.
This opposition is both on the level of the individual person and on the level of institutions such as
government and church.
Locke's monumental An Essay Concerning Human Understanding concerns itself with
determining the limits of human understanding in respect to God, the self, natural kinds and
artifacts, as well as a variety of different kinds of ideas.
It thus tells us in some detail what one can legitimately claim to know and what one cannot.
Locke also wrote a variety of important political, religious and educational works including the
Two Treatises of Government, the Letters Concerning Toleration, The Reasonableness of
Christianity and Some Thoughts Concerning Education.
Essay on Human Understanding
 Locke is often classified as the first of the great English empiricists (ignoring the claims of Bacon
and Hobbes).
 This reputation rests on An Essay Concerning Human Understanding.
 In writing An Essay Concerning Human Understanding Locke adopted Descartes' ‘way of ideas’;
though it is transformed so as to become an organic part of Locke's philosophy.
 Yet, while admiring Descartes, Locke's involvement with the Oxford scientists gave him a
perspective which made him critical of the rationalist elements in Descartes' philosophy.
 Some philosophers before Locke had suggested that it would be good to find the limits of the
Understanding, but what Locke does is to carry out this project in detail.
 Locke’s Essay presents a detailed, systematic philosophy of mind and thought.
 wrestles with fundamental questions about how we think and perceive, and it even touches on
how we express ourselves through language, logic, and religious practices.
 In the four books of the Essay Locke considers the sources and nature of human knowledge.
o Book I argues that we have no innate knowledge. (In this he resembles Berkeley and
Hume, and differs from Descartes and Leibniz.) So, at birth, the human mind is a sort of
blank slate on which experience writes.
o In Book II Locke claims that ideas are the materials of knowledge and all ideas come
from experience.
o Book III deals with the nature of language, its connections with ideas and its role in
knowledge.
o Book IV, the culmination of the previous reflections, explains the nature and limits of
knowledge, probability, and the relation of reason and faith
 the relationships among perception, thought, and language. As opposed to accepting the
possibility of directly receiving truth, he sees physical science as moving toward truth, but
knowledge as psychology.
 Outside world--sense perception--ideas--knowledge of ideas--reflection upon those ideas--ideas
as signs of real things and words as again removed
Book I
Locke’s Essay on Human Understanding
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In Book I, Locke lays out the three goals of his philosophical project:
o to discover where our ideas come from,
o to ascertain what it means to have these ideas and what an idea essentially is, and
o to examine issues of faith and opinion to determine how we should proceed logically
when our knowledge is limited.
attacks previous schools of philosophy that maintain a belief in a priori, or innate, knowledge.
contends that, on the contrary, no principle is actually accepted by every human being.
asserts human beings cannot have ideas in their minds of which they are not aware, so that
people cannot be said to possess even the most basic principles until they are taught them or
think them through for themselves.
confronts the theory of innate ideas and argues that ideas often cited as innate are so complex
and confusing that much schooling and thought are required to grasp their meaning.
Book II
 seeks to demonstrate where knowledge comes from.
 proposes that knowledge is built up from ideas, either simple or complex.
 Locke divides simple ideas into four categories:
o ideas we get from a single sense, such as sight or taste;
o ideas created from more than one sense, such as shape and size;
o ideas emerging from reflection; and
o ideas arising from a combination of sensation and reflection, such as unity, existence,
pleasure, pain, and substance.
 explains the difference between primary and secondary qualities.
o Ideas of primary qualities—such as texture, number, size, shape, and motion—resemble their
causes.
o Ideas of secondary qualities do not resemble their causes, as is the case with color, sound,
taste, and odor.
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discusses complex ideas, breaking them down into four basic types:
o modes, which are ideas that do not exist in and of themselves, such as qualities, numbers,
and other abstract concepts;
o substances, either self-subsisting things (such as a particular man or a sheep) or collections
of such things (an army of men or a flock of sheep);
o relations, such as father, bigger, and morally good; and
o abstract generals, such as “man” or “sheep” in general. Complex ideas are created through
three methods: combination, comparison, and abstraction.
Book III
 discusses abstract general ideas.
 Everything that exists in the world is a particular “thing.”
 General ideas occur when we group similar particular ideas and take away, or abstract, the
differences until we are left only with the similarities.
 We then use these similarities to create a general term, such as “tree,” which is also a general idea.
 We form abstract general ideas for three reasons:
o it would be too hard to remember a different word for every particular thing that exists,
o having a different word for everything that exists would obstruct communication, and
o the goal of science is to generalize and categorize everything.
 Nominal essences are the specific collections of observable properties from which we create an
abstract general idea.
 Real essences are the invisible structures and arrangements of corpuscles or atoms that allow for
those observable properties to be observable in the first place.
 Locke moves on to discuss language, pointing out natural weaknesses and common abuses of
language. The most significant problem with words is that they do not immediately and obviously
mean the same thing to all people.
 This problem has four main causes:
o a word may imply a very complex idea,
o the ideas that words stand for may have no constant standard anywhere in nature to judge
them against,
Locke’s Essay on Human Understanding
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the standard that ideas refer to may not be easily known, and
the meaning of a word and the real nature of the thing referred to by the word may not be
exactly the same.
 Locke also identifies six common abuses:
o people often use words without really knowing what these words mean,
o people use words inconsistently,
o people purposefully make terms obscure by using old words for new and unusual uses or by
introducing new terms without defining them,
o people mistakenly believe that words refer to things rather than ideas,
o people try to use words incorrectly to change their meaning, and
o people assume that others know what they are saying when they are not really being clear.
 Locke suggests four remedies to counteract the natural shortcomings and the abuses of language:
o never use a word without having a clear idea of what it means;
o try to recognize the same meaning for words as others do so that we can communicate with a
common vocabulary
o if there is the slightest chance that the meaning of your words will be unclear, define your
terms; and
o always use words consistently.
Book IV
addresses the nature of knowledge itself, asking what knowledge is and in what areas we can hope
to attain it.
identifies four sorts of agreement and disagreement that reason can perceive to produce knowledge:
 identity (blue is blue) and diversity (blue is not yellow),
 relation (two triangles with equal bases located between the same two parallel lines are equal
triangles),
 coexistence (iron is always susceptible to magnets), and
 realization that existence belongs to the ideas themselves and is not in the mind (the idea of
God and of the self).
 distinguishes between three grades or degrees of knowledge:
o intuition, when we immediately perceive an agreement or disagreement the moment the
ideas are understood;
o demonstration, which requires some sort of proof; and sensitive knowledge, which is about
the existence of an external world, roughly resembling the world as we perceive it.
o argues that we can never really develop a system of knowledge in natural philosophy.
 outlines three strategies for dealing with the problem of skepticism, or doubt about whether the world
exists outside of our minds.
o first strategy is to refuse to take the skeptic seriously.
o second strategy is to say that it doesn’t matter whether we doubt the existence of an outside
world or not.
o third line of attack involves seven marks of our experience that can best be explained by the
existence of an external world:
 there is a certain realness and strength of clarity to perception of an immediate object
that memories or products of the imagination do not have,
 we cannot get these ideas without the sense organ appropriate to them,
 we are able to receive ideas of this sort only in certain situations so it cannot be the
organs themselves that are responsible for producing the ideas,
 we receive ideas passively,
 some ideas are accompanied by pleasure or pain but the memories of those ideas
are not,
 our senses often bear witness to the truth of each other’s reports, and
 two different people can share the same experience.
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examines the relation between reason and faith.
 defines reason as being the faculty we use to obtain judgment and knowledge.
o Faith is the acceptance of revelation and has its own truths, which reason cannot discover.
Locke’s Essay on Human Understanding
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Reason, however, must always be used to determine which revelations truly are revelations
from God and which are the constructions of man.
 Finally, Locke divides all of human understanding into three sciences:
o natural philosophy, or the study of things to gain knowledge;
o ethics, or the study of how it is best to act; and
o logic, or the study of words and signs.
Locke’s Contribution
 effectively shifted the focus of seventeenth-century philosophy from metaphysics to the more basic
problems of epistemology, or how people are able to acquire knowledge and understanding.
 addresses many different aspects of human understanding and of the mind’s functions.
 replaces the theory of innate knowledge with his own signature concept, the tabula rasa, or blank
slate.
 tries to demonstrate that we are born with no knowledge whatsoever— we are all blank slates at
birth—and that we can only know that things exist if we first experience them.
 presents “simple” ideas as a basic unit of human understanding, claiming that we can break all of our
experiences down into these simple, fundamental parts that cannot be broken down any further.
 every idea is an object of some action of perception and thinking.
 An idea is an immediate object of our thoughts, something we perceive and to which we are actively
paying attention.
 We also perceive some things without ever thinking about them, and these things do not continue to
exist in our minds because we have no reason to think about them or remember them.