Lecture 14: Hume

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Lecture 14 Humes Radical Empiricism
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Todays Lecture

• In Todays Lecture we will
• Recap our investigation into empiricist theories
  of knowledge
• Briefly consider the problem of correspondence
  and Berkeleys arguments against Lockes theory
  of knowledge
• Become introduced to the radical empiricism of
  David Hume
• Critique and discuss Humes theory of knowledge
  and its implications on philosophy, metaphysics,
  science.

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Responses to Locke
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Responses to Locke
Lockes Theory of Knowledge All ideas
(knowledge) comes from experience There are two
forms of experience Sensation
(Outer) Reflection (Inner) All ideas are either
from inner experience or outer experience There
are no innate ideas, only innate faculties
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Lockes Theory of Knowledge
Idea of the water
Water itself
Mind
Reality
The idea of the water corresponds to a real object
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Epistemological dualism
Idea of the water
Inner Experience External Experience
1.
2.
3.
Water itself
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Responses to Locke
The Problem of Correspondence Representational
theories of perception maintain that everything
we know is an idea in the mind that represents or
corresponds to something outside of the
mind Problem How do we know if our ideas of an
object accurately correspond to the object
itself? All we have are ideas of objects We
cannot have knowledge of anything that is not an
idea Therefore, we cannot have knowledge of an
object apart from an idea Therefore, we can
never know if our ideas of water correspond to
the water itself
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Berkeleys Response to Locke
Idea of the water
Water itself
Mind
Reality
Berkeley argues that there is nothing more to an
object than the qualities we perceive (the
idea) We can never perceive the causes of things
we perceive
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Epistemological dualism
Idea of the water
Inner Experience External Experience
1.
2.
3.
Water itself
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Berkeleys theory of Reality
Idea of the water
Ideas exist only in minds All things are
ideas Therefore, all things exist only in minds
Mind
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Responses to Locke
Berkeleys Arguments for Idealism Esse est
Percepti (To be is to be perceived) All objects
(chair, water etc.) are sensible things A
sensible thing is a collection of qualities that
we perceive There is nothing more to any object
than the sum of its qualities All sensible
qualities exist only as ideas Therefore, objects
only exist in minds Nothing exists independently
of a perceiving mind

• The idea of a substratum (substance/matter) that
  is the cause of ideas, but free from qualities is
  incoherent. This is because we cannot
• have an idea of something that cannot be
  experienced
• perceive the causes of what we perceive
• conceive of anything without qualities.

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Responses to Locke

• In Summary
• Lockes theory of knowledge faces the following
  problems
• The problem of correspondence
• We can never be sure whether our ideas of an
  object correspond to the object itself
• There is an epistemological gap between our
  knowledge of an object and the object itself
• Berkeleys Criticisms
• We are never able to have an idea of anything
  that cannot be perceived
• The idea of physical substance is incoherent
• All that we can be sure of is that minds and
  ideas in minds exist
• We can never have access to the object itself

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David Hume
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David Hume

• David Hume
• Lived 1711-1776
• One of the great British empiricists
• Advocated a Radical form of empiricism
• Made important contributions to Metaphysics,
  Epistemology, Philosophy of Religion
• Humes radical empiricism has important
  consequences for the investigation into
  philosophy, religion and science

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David Hume

• David Humes Phenomenalism
• All knowledge is derived from and limited to
  appearances
• Appearances are presented to us in our
  perceptions
• Perceptions can be divided between
• Impressions
• Lively, Vivid Sensations
• Ideas
• Pale impressions / copies
• All ideas are derived from impressions
• All the mind possesses is a collection of
  perceptions

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David Hume

• David Humes Phenomenalism
• There are two bases of knowledge
• Relations of Ideas
• Ideas that are intuitively or demonstratively
  certain
• E.g. Geometry, Arithmatic, Logic, Algebra etc.
• Matters of Fact
• Ideas that pertain to the world
• E.g. The sun will rise tomorrow, This chair is
  red, etc.

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David Hume
Whats so radical about Humes radical
empiricism? Aristotle, Aquinas, Locke all
argue that we can have certain knowledge For
example This is a chair The chair is really
red The chair exists But! Hume argues that
these thinkers fail to follow empiricism to its
rational conclusions Hume If all knowledge
comes from perception Either Our ideas are
certain but not informative Or Our ideas are
informative but not certain
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Implications of Humes Radical Empiricism
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Implications

• The limits of knowledge
• Relations of Ideas
• Ideas that are intuitively or demonstratively
  certain
• E.g. Geometry, Arithmetic, Logic, Algebra etc.

Relations of ideas can give us certain
knowledge They dont teach us anything new They
have no bearing or relevance on reality
For Example Socrates is a man All men are
mortal Therefore Socrates is mortal
Doesnt teach us anything new Has no relevance
upon reality Certain
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Implications
The limits of knowledge 2. Matters of
Fact Ideas that pertain to the world E.g. The
sun will rise tomorrow, This chair is red,
etc.
Matters of fact can teach us new things about the
world But they can never be certain It is
always possible that they can be rendered
false Entirely dependent on perceptions
For Example Earth days are now 1.26 nanoseconds
faster
Teaches us something new about the world Cannot
be certain
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Implications
Hume Sense impressions have priority over
ideas There are no ideas without sense impressions
Humes attack on the principle of substance It
is natural to believe Descartes/Locke There
exists both mental and physical
substance Berkeley Physical substance does not
exist but mental substance (mind) does Humes
challenge Do we ever perceive substance?
No. Therefore, we cannot rationally claim that
substance exists
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Implications
Hume Sense impressions have priority over
ideas There are no ideas without sense impressions
Humes attack on the principle of the Self It
is natural to believe Berkeley/Locke/Descartes
That there is a thinking thing, a self, ego,
etc. Humes challenge Do we ever perceive a
self? No. Only many perceptions Therefore, we
cannot rationally claim that the self exists
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Implications
Hume Sense impressions have priority over
ideas There are no ideas without sense impressions
Humes attack on the principle of
Causality It is natural to believe That
every event has a cause / Causal
connection Humes challenge Do we ever
perceive a necessary connection? No. We
perceive that A occurs, then B occurs but we
dont perceive the necessary connection where A
causes B All we perceive is contiguity (things
close together) and succession We never
perceive causation! Therefore, we cannot
rationally claim that every event has a cause
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Implications

• Examples against causation
• At age 1 a child begins to
• Feed themselves
• Walk by themselves
• Learns simple words
• Receives their Measles, Mumps, Rubella
  vaccinations

For Example A child (A) receives their MMR
vaccinations, then (B) begins to feed
themselves A? B But! A did not cause B.
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Implications

• Implications for modern scientists
• All scientific theories must be limited to what
  can be observed or observed in principle
• All scientific claims are either
• Relations of ideas
• E.g. All mammals are warm blooded
• Or
• Matters of fact
• E.g. The Earth day is now 1.26 nanoseconds faster
• Scientific claims/laws/theories cannot be
  certain (only likely or unlikely)
• It is always possible that a scientific claim can
  be proved false because of future observations

Popper Scientific theories must be falsifiable
(Principle of Falsifiability) For example
Theories of the subconscious cannot be observed
or falsified therefore they are not scientific
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Summary
Summary Empirical (all) knowledge can only be
either Necessarily true but not
informative Or Informative but not certain All
ideas are derived from perceptions Any idea we
have that is NOT derived from perceptions should
be abandoned
When we run over libraries, persuaded of these
principles, what havoc must we make? If we take
in our hand any volume, of divinity or school
metaphysics, for instance let us ask, Does it
contain any experimental reasoning concerning
matter of fact and existence? No. Commit it
then to the flames for it can contain nothing
but sophistry and illusion. (David Hume,
Textbook, p.225)