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2. David Hume
British Empiricism – a belief system that all knowledge is based on ideas developed from sense data or sensory experience
David Hume( ) (Treatise on Human Understanding, 1739)
3 Minute Philosophy: David Hume

3. Empiricist Epistemology
The study of knowledge (how and what we can know)
Knowledge = true beliefs, thoughts, propositions
Truth = a belief or proposition is said to be true if it corresponds to reality
Ex: The proposition “this sentence has 5 words” is true if it actually has 5 words.
Empiricist epistemology:
knowledge consists of ideas that are true (correspond to reality)
Ideas are objects of cognition
All ideas/objects of cognition are derived from either sensation or reflection
In order for an idea to be true, it must ultimately have as its source sensory experience with sense date and it must be verified/checked by experience
All knowledge begins with experience and is limited to experience

4. Positivism
Also known as logical positivism and/or scientific positivism
Positivism: a radical 20th century empiricist position that maintains that propositions are meaningful if and only if they are:
Analytically true, i.e., logically true, true by definition
A triangle is a three sided object with internal angles that add up to 180 degrees
Synthetically true, i.e., true empirically, factually verifiable
This sentence has 5 words. The chalk is white
Any claims that are not true analytically or factually are meaningless
Hume’s Fork: propositions are true if they are about
Relations of ideas: “analytic a priori” claims
Matters of fact: “synthetic a posteriori” claims

5. Representational Realism
Epistemological position that all knowledge is based on ideas developed from sense data from sensory experience of the world
1st 2nd rd th The world Body Mind Knowledge Presents itself Sensation Cognition Expression Impression Idea True claim/belief
Objective TRUTH = Accurate representation of objects in reality
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6. PRIMARY AND SECONDARY QUALITIES
Primary qualities “resemble” (or “reside in”) an object even when we are not perceiving the object
Solidity
Extension
Figure (shape)
Motion or rest
Number
Objective knowledge
Secondary qualities do not “resemble” (or “reside in”) an object, but are “powers” of objects to produce sensations in our minds
Colors
Sounds
Tastes
Odors
Subjective knowledge

7. The Fate of Empiricism
With the success of Newtonian physics and Locke’s account of an empiricist metaphysics and epistemology
Empiricism seemed to clearly have the upper hand against rationalism
Hume comes along and shows that there is something deeply troubling about empiricism
It leads to a radical kind of skepticism
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8. “HUME’S FORK”: RELATIONS OF IDEAS AND MATTERS OF FACT
Mathematical statements, such as those found in geometry, algebra, and arithmetic
Tautologies, or logical truths, such as “A dog is a dog”
Known by reason
To deny them is to contradict oneself; therefore, they give us absolute certainty
But they have no empirical content
Matters of Fact
Involve sense experience
It is possible to logically contradict a matter of fact
Hume believes that if a claim of empirical knowledge cannot be reduced to a relation of ideas or a matter of fact, it should be discarded as knowledge. He challenges:
Any necessary connection between cause and effect
The notion of material substance
The notion of mental substance (“soul”)
Inductive reasoning
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9. Relations of Ideas vs Matters of Fact
Human knowledge falls into two kinds for Hume
Relations of Ideas– all a priori knowledge
Matters of Fact– all empirical knowledge
To decide which is which you apply the following rule
If the negation of the proposition in question is a contradiction then it is a Relation of Ideas
If not, a Matter of Fact
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10. RoI & MoF Matters of Fact Relations of Ideas
All bachelors are unmarried
All dogs have doggie anatomies and physiologies
All apples have colored skin with flesh surrounding a core of seeds
All triangles have three sides
A2+B2=C2
For any sentence S, either S is true or S is false
S can’t be true and also not true at the same time
Matters of Fact
78% of bachelors are messy
Whether a dog has short legs and a big bark
Whether an apple is red or green
Whether a triangle is 3x3x3 or 4x4x4
Subway fare is $2.00
The truth or falsity of S is dependent upon the circumstances
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11. RoI Relations of ideas consists of two parts
And the relations between them
E.g. my ideas BACHELOR and UNMARRIED MALE are related in such a way as to make it impossible for there to be a married bachelor
This is true for all relations of ideas
Their truth is independent of experience in the sense that one does not need to go and check to see if they are true
Mathematics and logic are purely formal systems of inter-related definitions
Numbers do not need to exist to make it true that
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12. MoF
Matters of Fact on the other hand have their truth determined by the way that the world happens to be
Hume argues that the idea of cause and effect is a MoF because it fails to meet the two criteria of something that is a priori
To deny it is not a contradiction
We cannot, without experience, predict what the effect of any given cause will be
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13. Analytic apriori vs. Synthetic aposteriori
Relations of Ideas
Deduction
True by definition (universally and necessarily)
Absolutely certain
Snythetic aposteriori
Matters of Fact
Synthetic aposteriori
Induction
Truth is contingent
Probability

14. Summary of the Argument so Far
All human knowledge is either learned from experience (matters of fact) or from reason (relation of ideas)
MoF are composed of ideas copied from impressions and are true or false depending on the kind of experience we have
‘dogs can fly’ vs. ‘dogs don’t like cats’
RoI are true or false depending on the relations that hold between the ideas
‘triangles are four-sided objects’ vs. ‘triangles have three sides’
We can tell the difference between these by seeing what happens when we negate the sentence in question
If it is a contradiction it is a RoI, if not a MoF

15. The Argument III
All of our ideas must come from one of these two sources
One of the most important ideas we have is the idea of causation
The idea of a necessary connection between events
Same cause=same effect EVERY TIME
All of science is based on this idea
All of our common sense knowledge about the world based on this idea

16. The Problem of Causality
So, where does the concept of causality come from?
Is it an innate idea? No
Is it an idea that is necessitated by and/or related to other ideas? That is, is it derived from some other idea, such as thing, self, substance, God, etc.? No
Is it an idea that can be traced back to an experience of a primary quality in the world? NO

17. Causality ≠ a relation of ideas
Causality is not an RoI
To deny any causal relation is not a contradiction
It is always possible to imagine something else happening
But we can’t imagine a square circle
We have to go and check
We can’t tell what causes what without experience

18. Causality ≠ MoF So, it must be a MoF
That means that the idea of necessary connection must be traceable back to an impression
Otherwise it is a meaningless idea
But when we look at any example of A causing B all we see are separate events
We see A happen (the pool stick hits the ball)
Then we see B happen (the second ball moves)

19. Causality ≠ MoF (#2)
We do not see anything that connects the two events
There is nothing that we can point to and say that it is the thing that makes the second event the necessary consequence of the first event
So, Hume concludes, we have no rational reason (i.e. based on our experience or reason) to believe that the laws of physics are necessary and universal

20. Causal claims are inductively fallacious
All inductive knowledge is based on the fallacy of assuming that the future will resemble the past
But just because something has happened for a long time is no guarantee that it will always happen
So, the sun may have risen everyday so far, but who can say with certainty that it will rise tomorrow?
Just like problem of black swans

21. Solution: Causality is the product of habit
So where does the idea come from?
It comes from ‘a habit of expectation’
We see A happen
We see B happen right after
This is repeated
Soon when we see A happen we come to expect that B will happen right after

22. Causality = a projection of the Mind
It is the subjective feeling of expectation that we mistakenly ‘project’ out onto the events that we observe
We cannot know if there is anything more to the word than this
This is an epistemological claim: we can’t know if there is a necessary connection between events
NOT a metaphysical claim: There is no necessary connection between events

23. Pavlov & Classical Conditioning
We have been trained by nature to expect certain events upon seeing certain other events
Just like Pavlov’s dog
You ring the bell and bring some food
The dog salivates
Repeat
Soon the dog salivates when hearing the bell whether or not food comes
The dog has come to expect ‘bell then food’
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24. Classical Conditioning II
Now if the dog were to reason to itself as follows,
Every time the bell has rang food has appeared
This has happened everyday of my existence, every since I was a puppy
I can infer from this that the next time the bell rings, food will appear
We could easily see that the dog has made a mistake
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25. Classical Conditioning III
There is no necessary connection between bell ringing and food appearing in nature
How can we tell that this is not the way nature is in reality?
Nature is regular (so was the bell ringing/food bringing relationship)
Things so far have happened regularly and predictably
But we have no reason to believe that it must continue
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26. READING CRITICALLY: ANALYZING HUME’S CASE FOR SKEPTICISM
Is Hume correct to call the appeal to God’s existence to support the existence of an external world “philosophical hypocrisy”? Why or why not?
Summarize Hume’s arguments against certain knowledge of the principle of cause and effect. Do you agree with his reasoning? Why or why not? Construct an alternative argument to convince Hume that the principle of cause and effect is valid and give examples.
Would your agreeing with Hume’s critique of knowledge claims about cause and effect and induction change the way you live your life? Why or why not?
Hume splits his practical life from his theoretical philosophical commitments. Do you agree that such a split is possible? Should our choices in life reflect our epistemological convictions? Describe an example to support your point of view.
Hume believes that all metaphysical beliefs (that is, any belief not based on direct sense experience) should be “committed to the flames” because they cannot be empirically justified. This would include all beliefs regarding God, human freedom, universal moral laws, and so on. Do you agree with Hume? If not, how would you rebut his arguments?
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27. KANT’S “COPERNICAN REVOLUTION”
“Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to extend our knowledge of objects by establishing something in regard to them by means of concepts have, on this assumption, ended in failure. We must, therefore, make trial whether we may have more success if we suppose that objects must conform to our knowledge.” –Critique of Pure Reason
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28. Kant’s Dogmatic Slumber
Kant is disturbed from thinking that everything in science is fine by Hume’s argument
Empiricism cannot deliver necessary truths
‘experience can teach us that something is the case but it cannot teach us that it must be the case’
Yet science claims to discover necessary truths about nature
Even worse, Hume claimed to have shown that Human Beings are essentially irrational
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29. Transcendental Idealism
Kant agrees with Hume that we cannot learn that the causal relation is necessary and universal from experience
But Hume has not shown that we can’t have a priori knowledge
For Hume something was a priori if we could not deny it without contradiction
For Kant something is a priori if is knowable completely independently of experience
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30. An Analogy
Suppose that I told you that there were 25 people in a room on the second floor of some building
What could you know about that room?
Quite a bit actually
Its size, what it was made out of, etc.
Kant’s strategy is similar
He wants to know what we can know given that our experience is the way that it is
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31. The Structure of Experience
How could our experience be the way that it is?
How is it?
Objects are located in space and time
Can you imagine an object which was not at any place? No
This is something that we can know a priori
It is not dependent on experience
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32. Conditions of all Possible Experience
It is the pre-condition for any experience at all
Just like space in the room is a precondition of having objects in the room
So too space is a necessary condition of any possible experience
Thus we can know with absolute certainty that whatever experiences we do have
They will all take place at some time and at some particular place
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33. The A Priori So Kant concludes that there is pure A priori knowledge
‘pure’ because it does not depend on experience
But is rather the pre-conditions for any possible experience
It is necessary
It is not possible to have experience without space
And universal
All experiences will be in space
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34. Analytic vs. Synthetic
An analytic truth is one that is true by virtue of the meaning of the words themselves
All bachelors are unmarried males
They do not add to our knowledge
Synthetic truths are true in virtue of the kind of experience we have
All bachelors are messy
They do add to our knowledge
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35. Hume’s Mistake Hume’s criterion for being a priori
P is a priori if the denial of p is a contradiction
Let him divide all of our knowledge into that which was necessary (RoI) and that which was contingent (MoF)
Kant argues that we really have four categories
Analytic & A priori– truths which are true by definition and also necessary and universal
All analytic truths are a priori
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36. Hume’s Mistake II
Analytic & A posteriori– truths which are true by definition but also discovered by experience
Kant denied that there were any such truths
Synthetic A posteriori– Adds to our knowledge and learned from experience
Synthetic A priori– Adds to our knowledge and also necessary and universal
Hume denied that there were any such truths
That was his mistake
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37. Kant’s 4 Distinctions ??????? A Posteriori A Priori Analytic 7+5=12
All Bachelors are unmarried males
???????
Analytic
All triangles have three sides
7+5=12
Dogs bark
Apples taste good
Cause & effect
Synthetic
!!!!!!
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38. Synthetic A Priori Knowledge
So Kant’s answer to Hume is his theory of synthetic a priori knowledge
Take ‘fire causes pain’
It is synthetic, it adds to our experience
But it is also a priori, that is, necessary and universal
It is a priori in the sense that we can tell by looking at the structure of our experience that it must be a certain way
This Kant calls phenomena
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39. Phenomena vs. Noumena
The phenomenal world is the world as it appears to us.
It is the world that we see touch taste etc.
The noumenal world is the way that the world is in-itself
The world as it is when no one is looking at it
All we can know is the way our experience of the world will be
We can’t know the noumenal world
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40. Phenomena v. Noumena II Wasup? Hi Noumena Understanding Sensibility
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41. Kant’s Philosophy of Mind
The mind has two components
Sensibility
Understanding
Sensibility takes in ‘raw’ unorganized noumena and organizes it into phenomena (our experience)
Each has their categories that they use in order to construct our experience
The sensibility has Space and Time
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42. Kant’s Philosophy of Mind II
The understanding has 12 categories
Unity, plurality, totality, reality, negation, limitation, substance/property, cause & effect, community, possibility/impossibility, existence/non-existence, and necessary/contingent
With these categories, and the two from the sensibility, our mind constructs our experience
We can know with absolute certainty that our experience will conform to the categories
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43. Kant’s Philosophy of Mind IV
That is the only way that experience like ours is possible
The same cause must bring about the same effect or else our experience would be like a dream
Now here, now there…
Yet this comes at a heavy cost
Science studies our experience of the world
It does not, cannot, study the noumenal world
How can I every talk to you?
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44. Phenomena v. Noumena IIIHi
Wasup? Hi
Wasup? Me
You
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45. Kant’s Philosophy of Mind V
Kant called this a Copernican Revolution in philosophy
Instead of the mind passively acting like a recorder of an outside reality
Kant sees the human mind as actively constructing reality
This is his mix of Rationalism and Empiricism
Empiricism– science is synthetic knowledge
Rationalism– but based on a priori categories
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46. KANT ON THE SYNTETIC A PRIORI AND THE PHENOMENAL AND NOUMENAL WORLDS
THE SYNTHETIC A PRIORI
THE PHENOMENAL AND NOUMENAL WORLDS
Necessary and universally true
a priori—can be discovered independently of experience
Synthetic in the sense that it provides us with genuine information regarding our experience in the world
phenomenal reality is the world as we constitute it and experience it
noumenal reality is the world beyond our perceptions, reality “in-itself”
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47. APPLYING KANT’S THEORY: THE ASSASSINATION OF MALCOLM X
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48. ALLISON JAGGAR: EMOTIONS SHAPE OUR UNDERSTANDING
Jaggar believes that the “new science” of Newton and Galileo spawned a wide split between reason and emotion, so that “dispassionate” reason was considered the only source of knowledge
She argues that “dispassionate investigation” is a myth, and that emotions should be incorporated into our epistemological framework, including the framework of scientific knowledge
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