Transcript Lecture 13: Hume’s Radical Empiricism

LECTURE 14:
HUME’S RADICAL EMPIRICISM
In Today’s Lecture we will:
1. Recap our investigation into empiricist theories of knowledge
2. Briefly consider the problem of correspondence and Berkeley’s arguments
against Locke’s theory of knowledge
3. Become introduced to the radical empiricism of David Hume
4. Critique and discuss Hume’s theory of knowledge and its implications on
philosophy, metaphysics, & science.
TODAY’S LECTURE
RESPONSES TO LOCKE
Locke’s 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
Experience
Sensation
Reflection
Passive
Simple Ideas
Complex Ideas
RESPONSES TO LOCKE
Active
Locke’s Theory of Knowledge
Idea of the
water
Water itself
Reality
Mind
The idea of the water corresponds to a real object
Epistemological dualism
Inner Experience
1.
Idea of the
water
External Experience
3.
Water itself
2.
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
RESPONSES TO LOCKE
Berkeley’s Response to Locke
Idea of the
water
Water itself
Reality
Mind
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
Epistemological dualism
Inner Experience
1.
Idea of the
water
External Experience
3.
Water itself
2.
Berkeley’s theory of Reality
Idea of the
water
Ideas exist only in minds
All things are ideas
Therefore, all things exist only in minds
Mind
Berkeley’s 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:
a) have an idea of something that cannot be experienced
b) perceive the causes of what we perceive
c) conceive of anything without qualities.
RESPONSES TO LOCKE
In Summary
Locke’s theory of knowledge faces the following problems:
1. 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
2. Berkeley’s 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
RESPONSES TO LOCKE
DAVID HUME
David Hume:
o Lived 1711-1776
o One of the ‘great’ British empiricists
o Advocated a Radical form of empiricism
o Made important contributions to
Metaphysics, Epistemology, Philosophy
of Religion
o Hume’s radical empiricism has
important consequences for the
investigation into philosophy, religion
and science
DAVID HUME
David Hume’s Phenomenalism
All knowledge is derived from and limited to appearances
Appearances are presented to us in our perceptions
Perceptions can be divided between
1. Impressions
Lively, Vivid Sensations
2. Ideas
Pale impressions / copies
All ideas are derived from impressions
All the mind possesses is a collection of perceptions
DAVID HUME
David Hume’s Phenomenalism
There are two bases of knowledge:
1. Relations of Ideas
Ideas that are intuitively or demonstratively certain
E.g. Geometry, Arithmatic, Logic, Algebra etc.
2. Matters of Fact
Ideas that pertain to the world
E.g. The sun will rise tomorrow, This chair is red, etc.
DAVID HUME
What’s so radical about Hume’s 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
DAVID HUME
IMPLICATIONS OF HUME’S
RADICAL EMPIRICISM
The limits of knowledge:
1. 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 don’t 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
Doesn’t teach us anything new
Has no relevance upon reality
Certain
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
IMPLICATIONS
Teaches us something new about
the world
Cannot be certain
Hume: Sense impressions have priority over ideas
There are no ideas without sense impressions
Hume’s 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
Hume’s challenge:
Do we ever perceive substance? No.
Therefore, we cannot rationally claim that substance exists
IMPLICATIONS
Hume: Sense impressions have priority over ideas
There are no ideas without sense impressions
Hume’s 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.
Hume’s challenge:
Do we ever perceive a self? No. Only many perceptions
Therefore, we cannot rationally claim that the self exists
IMPLICATIONS
Hume: Sense impressions have priority over ideas
There are no ideas without sense impressions
Hume’s attack on the principle of ‘Causality’:
It is natural to believe:
That every event has a cause / Causal connection
Hume’s challenge:
Do we ever perceive a necessary connection? No.
We perceive that A occurs, then B occurs;
but we don’t 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
IMPLICATIONS
Examples against causation:
At age 1 a child begins to:
o
o
o
o
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.
IMPLICATIONS
Implications for modern scientists:
1. All scientific theories must be limited to what can be observed or observed in
principle
2. All scientific claims are either
i. Relations of ideas
E.g. All mammals are warm blooded
Or
ii. Matters of fact
E.g. The Earth day is now 1.26 nanoseconds faster
3. 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
IMPLICATIONS
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)
SUMMARY