Class notes through 10/28/2025
8/26/2025
Introduction to Philosophy
Grades:
50% Weekly reflections/responses (Assignments page)
20% Essay (mid-term)
20% Exam (final)
10% Attendance
Maximum of 14 absences before failing course
You get 1.5 points for each day you come to class. There are 28 class meetings (= 42 points).
If you attend 21 class meetings, you will get 100% on your attendance grade (31 points). If you attend more than 21 class meetings (up to 28) you can earn 135% on your attendance grade.
8/28/2025
[Philosophy Club: Tuesday, September 2 at 5:00 in CAS 436 (“The Cave”)]
Could two things exist that are EXACTLY alike?
When asked what soft skills they most need in employees, the three most mentioned usually include: Critical Thinking, Communication, and Ethical Judgment.
Philosophy excels in teaching 2/3 of these … or maybe 2.5/3 … because philosophy teaches clear and precise expression in language.
Thinking of Law School?
Business school?
Oh yeah? Well, what about Medical School?
(Why 1998? Because that was the last year before philosophy got lumped in with other Humanities majors)
Other grad school?
(By GRE section):
Philosophy majors outperform other humanities majors in earnings
Could two things be exactly alike?
Leibniz proposed:
Identity of indiscernibles: If x and y are exactly alike, then x=y.
Indiscernibility of identicals: If x = y, then x and y are exactly alike.
Leibniz’s Law: X = y if and only if x and y have all the same properties.
“All electrons are exactly alike.”
What makes 2 things 2 things of the same type?
Socrates
Plato
What makes 2 llamas alike?
1. These two things have something in common.
2. Therefore, these two things have some one thing in common. (Plato calls this a FORM.)
Forms are abstract objects that exist apart from us and our minds.
There is a Form of Llamas.
There is a Form of Alpacas.
If the Forms are abstract, how do we know them?
Plato (Socrates): The soul knows the Forms by being like them.
The soul is therefore unchanging in nature. Indestructible.
Dualism between body and soul.
How did we get from llamas to souls?
Some ideas FOLLOW FROM others (or at least appear to). This happens by connecting principles. Inferences.
Universals: principles that apply to multiple instances
9/2/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Also today in CAS 436 = meet some philosophers & eat snacks]
If God exists, do you think he has a sense of humor?
Can we KNOW whether or not God exists?
Arguments in philosophy are NOT disagreements, but rather (ideally) objective reasons in support of a claim.
The claim that is being advanced is the conclusion, and the reasons offered in support of the conclusion are premises.
Today is Tuesday, therefore today is Tuesday.
1. Today is Tuesday.
2. Therefore, today is Tuesday.
An argument that is trivially true is called a “tautology”.
A “non-sequitur” is an argument that is completely bad in respect of its logical structure. It is an argument where one cannot legitimately infer the conclusion from the premises.
1. Today is Tuesday.
2. Therefore, you should all give me all your money.
Every argument is good or bad in either or two ways:
- In respect of structure (logic)
- In respect of content (are the premises true or at least reasonable to believe?)
1. All ducks are mammals.
2. Daffy is a duck.
3. Therefore, Daffy is a mammal.
Are there any good arguments for or against the existence of God?
1. Something exists.
2. Therefore, God exists.
How might you fill out this argument to make it compelling? (Make it so that it is no longer a non-sequitur.)
1. God exists.
2. Therefore, God exists.
1. A necessary being exists.
2. Only God could be a necessary being.
3. Therefore, God exists.
1. The universe exists (and began to exist).
2. Everything that began to exist must have had a cause for its existence. (Principle of Universal Causation)
3. The universe must have had a cause.
4. Nothing can be its own cause. (No self-causation)
5. Something other than the universe caused the universe.
6. That must be God.
7. Therefore, God exists.
9/4/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
One prominent philosopher once said that one of the most important questions is “Why is there something rather than nothing?”
What do you think the answer is to this?
Principle of Sufficient Reason (PSR):
- There must a reason for EVERYTHING.
- For any given truth, there must be an explanation as to WHY it is true (rather than not). PSR is true. Philosophers have generally divided all true statements into two classes: analytic truths and synthetic truths. A claim is analytically true if it is true in virtue of meanings or definitions or the concepts involved (example: all squares have 4 sides). A synthetic truth is one that is true in virtue of the facts we find in the world.
- For anything that exists, there must an explanation as to WHY it exists (rather than not).
- For any way that things are, there must be an explanation as to WHY things are as they are (rather than some other way).
1. Something exists.
2. Therefore, God exists.
Anyone who wants to limit the Principle of Sufficient Reason to a more restricted form than this one, has to JUSTIFY such restriction.
Ad hoc fallacy = asserting a claim just in order to salvage another claim that one wants to protect from criticisms.
Things that exist can be conceptually divided into two groups: Those that exist because of something else, and those that exist because of themselves.
1. Everything that exists is either a dependent being or a necessary being. (or a brute fact being)
2. The universe exists.
3. The universe is either a dependent being or a necessary being.
4. It is impossible that only dependent beings exist. (Because an infinite regress of dependent beings violates the Principle of Sufficient Reason.)
5. Therefore, there has to be at least one necessary being.
6. The universe can’t be a necessary being. (first, because the universe can be conceived not to have existed, second because the universe changes – and necessary beings must be unchanging).
7. Something other than the universe is a necessary being.
8. That thing is God.
9. Therefore, God exists.
Each dependent being is explained by another dependent being.
No dependent being goes unexplained.
But what explains the totality of dependent beings?
(Why are there ANY dependent beings at all, rather than none?)
Is asking for an explanation over and above the explanations of all members of a series a “fallacy of composition?” (Is there more to explaining a series than explaining all members of the series?)
9/9/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Does the existence of beauty count as evidence of God’s existence?
Evidence is always evidence for or against
Information that strengthens or weakens support for a claim.
The claim is either made more or less reasonable (or probable) with the evidence than without.
Could the exact same information be both evidence for and evidence against a claim?
Teleological arguments
Design argument
Analogical design argument
William Paley
Functional complexity: complex structure together with a function performed in virtue of that structure that would not otherwise be possible.
1. Both artifacts such as watches and living structures such as the human eye exhibit functional complexity.
2. Artifacts have this because they are designed.
3. Probably, similar effects have similar causes when there are no preferable explanations for the similarity of the effects.
4. Therefore, living structures have functional complexity because they are designed.
5. Only God could have designed living structures.
6. Therefore, God exists.
3*. It is reasonable to infer that similar effects have similar causes if we have no better alternative explanation for the similar effect.
3.5*. We have no better alternative explanation for the FC of living structures other than design.
Some possible explanations:
E1: Supernatural design
E2: Spontaneous natural production
E3: Evolutionary production through natural selection (and other mechanisms)
Does God really provide a better explanation for FC than chance?
*
What, exactly, makes one explanation BETTER than another?
(Empirical evidence)
Consider:
Where did the universe come from?
E1: It spontaneously popped into existence from nothing.
E2: It was popped into existence by God.
What, exactly, is an explanation?
An explanation consists of 2 parts:
- The explanandum = that which is to be explained.
- The explanans = that which does the explaining.
The explanans has to be different from the explanandum.
Example:
‘Explain motion.’
‘Motion is what happens when something moves.’
v.s.
‘Motion is when a single object changes from one location at one time to a different location at a later time, (passing through intervening the space during the interval’).
The goal of an explanation is to produce better understanding after the explanandum has been replaced by the explanans.
So: Does God really explain FC?
How, exactly?
Here’s the argument again:
1. Both artifacts (e.g., a watch) and organic objects (e.g., an eye) exhibit FC.
2. Artifacts have FC in virtue of being designed.
3. Similar effects have similar causes.
4. Therefore, organic objects were designed.
5. If organic objects were designed, then God designed them.
6. If God designed them, then God exists.
7. Therefore, God exists.
Consider premise 5.
David Hume complains that the design argument violates the principle that: Posited causes can only be justified to the extent that they are necessary to account for the effect.
So can we infer God (with
all traditional attributes) rather than some ‘lesser god’?
9/11/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Could a perfect designer produce an imperfect design?
Probabilistic design argument
1. Living structures exhibit functional complexity (FC).
2. It is vastly improbable that all the FC we find resulted from purely natural causes.
3. It is not vastly improbable (or at least less improbable) that all the FC we find resulted from supernatural causation.
4. Therefore, probably, FC resulted from supernatural causation.
5. If that is so, then the supernatural cause is probably God.
6. Therefore, probably, God exists.
In premise 2 the basis of the improbability judgment is generally made empirically.
But in premise 3, the basis of the improbability judgment is NOT made empirically (because there are no KNOWN cases of supernatural causation).
The probability judgment in 2 appears to be objective while 3 appears to be subjective.
What, exactly, is an explanation?
An explanation consists of two parts:
1. The explanans: the part that does the explaining
2. The explanandum: the part that is to be explained.
The explanans has to be different from the explanandum.
Example:
‘Explain motion.’
‘Motion is what happens when something moves.’
vs.
‘Motion is when a single object changes from one location at one time to a different location at a later time, (passing through the intervening space during the interval’).
The goal of an explanation is to produce better understanding after the explanandum has been replaced by the explanans.
So: Does God really explain FC?
How, exactly?
Do we really understand the existence of FC better if we say God did it?
(“God of the gaps”)
A similar problem can be posed for cosmological arguments:
Claim: “God made the universe.”
Query: “How, exactly, did God make the universe?”
If the query can’t be answered, does appealing to God really explain the existence of the universe at all?
Fine Tuning Design argument (condensed):
The conditions that make it possible for our universe to support life are vastly improbable on naturalism. They are more probable if God exists. So, probably, God exists.
Once again, we have to consider the bases of the probability assessments.
9/16/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
If you could change one thing about the world, what would it be?
Argument from Evil
Logical Argument from Evil – It is logically impossible that both God and evil exist
Omnipotent = all-powerful
Omniscient = all-knowing
Omnibenevolent = all-good
Classic formulation:
1. If God exists, then he is omnipotent, omniscient, and omnibenevolent.
2. If God is omnibenevolent, he doesn’t want evil to exist.
3. If God is omniscient, he knows how to prevent evil from existing.
4. If God is omnipotent, he has the power to prevent evil from existing.
5. Evil exists.
6. God does not exist.
(Strictly speaking this argument is structurally bad because it is missing a linking premise.)
A being B is omnipotent =df. If B wills some logically possible state of affairs S, then S exists.
Stone paradox: Can God create a stone too heavy for him to lift?
Suicide paradox: Could God commit suicide?
LAE:
1. If God exists, God is omnipotent and omnibenevolent.
2. If God is omnibenevolent, then he wills a world without evil.
3. Evil exists in the world.
4. A world without evil is logically possible.
5. Therefore, God does not exist.
“Free Will Defense”
Most people know that free will is often invoked to counter the argument from evil.
But it isn’t immediately clear HOW free will helps.
LAE (above) is logically valid (structurally good). This means to reject the conclusion, at least one premise must be rejected as false (or at least doubtful). But which premise?
I think the strongest response actually rejects the above definition of omnipotence.
Omnipotence: A being B is omnipotent if and only if for any logically possible state of affairs S that does not depend on the free will of some creature, if B wills S then S exists.
Free will good = a good that results from the exercise of someone’s free will.
It’s better if I do a good thing of my own free will than if I am compelled to do it.
A world in which a significant number of free will goods exists is better than a world in which only compelled goods exist.
It is at least logically possible that the current world which contains both free will goods and free will evils is better than any world God could have created in which only compelled goods exist.
9/18/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Do you think all the suffering that exists in the world is deserved?
It is generally conceded in philosophy of religion that the LAE is unsuccessful.
If there is even one POSSIBLE scenario under which
both God and evil coexist, the LAE is flawed.
The concept of moral negligence is that moral responsibility attaches not only to actions (what we do), but also to omissions (what we fail to do or allow to happen).
The basic claim behind the Evidential Argument from Evil (EAE) is this:
An omnipotent, wholly good being will prevent any instance of evil (or suffering) that it can unless doing so would thereby either allow an equal or worse evil or prevent a greater good
(otherwise it would be morally negligent).
To put it another way:
If an omnipotent wholly good being exists, then the only evils that exist are ultimately justified.
To say that an evil is ultimately justified is to say that when all considerations are taken into account, it is better (or just as good) that the evil be permitted than prevented.
My version of EAE:
1. If God exists, then every evil is ultimately justified.
2. It is implausible that every evil is ultimately justified (although, it is logically possible that every evil is ultimately justified).
3. Therefore, it is implausible that God exists.
Plausibility differs from possibility. Mere possibility is not enough for a rational justification or explanation of behavior.
This argument is inductive rather than deductive.
Unlike deductive arguments, inductive arguments are capable of having all true premises but a false conclusion. (To show this is to give additional considerations that defeat the argument. Deductive arguments cannot be defeated.)
What could defeat the EAE?
Why is it supposed to be implausible that every evil is ultimately justified?
Primarily, we are supposed to accept Premise 2 because we can’t think of any justifications for a lot of the evils we observe.
Also, many of the justifications we CAN think of are implausible.
Suppose you know that Snidely is planning to murder Nell. You have the ability to prevent this.
What could justify you in allowing the murder?
A lot of possibilities are implausible:
“I didn’t want to interfere with Snidely’s free will.”
“Maybe by killing Nell, Snidely prevented even worse things from happening?”
“Nell deserved death for things she did in the past (or in a past life).”
Most theists believe that we cannot legitimately apply the standards of moral justification we use for humans to God, because God is omniscient and therefore knows things we don’t (or can’t).
This position is called “skeptical theism”.
1. If God exists, then his knowledge of the totality of goods and evils and the relations that obtain between them vastly outstrips ours.
2. If God's knowledge of the totality of goods and evils and the relations that obtain between them vastly outstrips ours, then it is very likely that at least one evil will exist that God will see as ultimately justified but we will not.
3. If it is very likely that at least one evil will exist that God will see as ultimately justified but we will not, then given any particular evil E that we do not see as ultimately justified, it is at least as likely as not that E is ultimately justified.
4. If given any particular evil E that we do not see as ultimately justified, it is at least as likely as not that E is ultimately justified, then it is not implausible that every evil is ultimately justified.
5. Therefore, if God exists, then it is not implausible that every evil is ultimately justified.
9/23/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Does a caterpillar have free will in choosing whether to go up or down?
What, exactly, is free will?
Is free will compatible with determinism?
Yes: Compatibilism
No: Incompatibilism
What, exactly, is determinism?
Combination of two causal principles:
Universal causation: Every event must have a cause.
Causal uniformity:
Strong: Given exactly the same causes, the exact same effects must follow.
Weak: Given relevantly similar causes, relevantly similar effects follow.
LaPlacian demon: (Pierre LaPlace) Given a complete knowledge of the state of material reality at some time and perfect knowledge of the laws of nature, every subsequent event would be perfectly predictable.
Incompatibilists say that if determinism is true, then there is no free will.
So, for them, the whole question is whether or not determinism is true.
Two varieties of incompatibilism:
Hard determinism: Determinism is true, and so we have no free will.
Libertarianism: We do have free will, and so determinism is false.
Sometimes libertarianism is called “contra-causal free will” (i.e., against the field of physical causes)
Why accept hard determinism rather than libertarianism?
Mainly because we have never observed a case where we knew an event not to have a cause.
Some people think (wrongly) that it is a conceptual truth that every event has a cause.
The BIGGEST problem for determinists has been the turn toward quantum physics.
Quantum Mechanics includes a commitment (usually) to irreducible indeterminacy. Some events at the very small level happen spontaneously without being deterministically caused.
Determinism appears to be false.
Some hard determinists think that determinism might be true after all (even in quantum physics).
But most accept a position called “near determinism” according to which the “macro world” is deterministic except in the RARE cases where macro-scale events narrowly depend on micro-scale indeterminism.
But also, even if material reality is ultimately indeterministic, how is this at all relevant to free will?
(We’ll come back to this.)
Incompatibilism: Either determinism or free will, but not both.
Hard determinism: Determinism is true, so there is no free will.
Libertarianism: Free will exists, so determinism is false.
Primary motive for incompatibilism is a commitment to the ‘Alternatives Principle’
S performs an action A1 freely at a time T only if at T S has the power to perform at least one alternative action A2 instead of A1.
If determinism is true, then no one ever has the power to perform any alternative action to whatever action they are determined to perform.
Hard determinists maintain that all alternative possibilities are really illusory (they are ‘epistemic possibilities’ but not ‘real possibilities’).
Libertarians maintain that we DO sometimes have genuine alternatives when we make choices, and therefore determinism is false.
Libertarians often argue that my actions often FEEL free to me, and therefore, I am justified in thinking they really are free.
“One person’s modus ponens is another’s modus tollens.”
Modus ponens:
If P, then Q.
P.
Therefore Q.
Modus tollens
If P, then Q.
Not-Q.
Therefore, not-P.
9/25/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Is free will
all-or-nothing or does it come in degrees?
Compatibilism affirms that determinism could be true but we could still have free will.
A better expression of compatibilism is that the truth or falsity of determinism is irrelevant to the question of whether or not we can have free will.
Compatibilists reject the alternatives principle as being part of what defines free will.
Rather, compatibilists think that the concept of free will needs to be defined in some other way than in terms of alternatives.
Compatibilism is mainly motivated by the ‘Reasons Principle’:
S performs A freely at T only if A is consistent with the totality of reasons S has at T for acting.
Compatibilism suggests that what really matters to a choice being “free” is that it is consistent with our internal motivations for acting.
Example 1: John Locke’s locked room example.
Example 2: Free money.
Example 3: Pencil in the eye.
Voluntarism is the position that you have a choice about something (that whether or not you do it is voluntary).
One of many things the German philosopher Immanuel Kant is famous for his saying, “’Ought’ implies ‘can’.”
Any claim that someone ought to behave in some way presupposes that it is possible for them to do so.
Rationality is generally considered to be prescriptive (that is, you ought to be rational).
So, prescriptive rationality implies rational voluntarism.
Rational voluntarism is a common assumption in advocating the teaching of logic, critical thinking, and philosophy.
Why bother teaching someone the difference between good and bad reasoning if no one has any choice about whether or not to put such knowledge to use?
If determinism is true, then it is determined whether or not you will be rational.
If you are determined not to be rational, then there seems no point in advising you to be rational.
This can be generalized to any type of advice, whatsoever.
If I advise you to avoid smoking, this advice seems pointless if you have no ability to avoid smoking.
The problem here relates to the position known as fatalism.
Can determinism be meaningfully distinguished from fatalism?
Fatalism can be defined as the view that if determinism is true, then nothing we do can change what happens.
Does determinism imply fatalism?
Does compatibilism imply fatalism?
In one sense, fatalism is certainly true:
If event E is determined to occur, then E will, in fact occur. E cannot be prevented except by changing something in the series of causes that determine E.
. . . C3 -> C2 -> C1 -> E
But each member of this series is determined and could not have happened differently given its causes, and so on.
Since no one can change what is in fact determined to happen, then nothing we do can change what happens.
But fatalism is false if it is understood as the view that nothing we do can change what happens (or that whatever is determined to happen will happen whether or not we try to prevent it).
Suppose a fatalist argues as follows:
If I am fated to die by drinking poison, then I will die by drinking poison, and nothing I do can change this. But if I am NOT fated to die by drinking poison, then I will not die by drinking poison. Therefore, whether or not I drink this poison in front of me makes no difference to the question of whether I die by drinking poison.
That is, fatalism supposes that our own choices/actions make no difference to what happens. But this is clearly false.
Suppose you consider whether or not you will follow the advice not to take up smoking.
If you are a fatalist, you will argue that either your smoking or your not smoking is determined, and therefore whatever you decide is irrelevant.
But a compatibilist will respond that your decision is also part of what will determine whether or not you smoke.
The fatalist reply is that how you decide is also determined.
The compatibilist admits this but denies that this gives you a reason not to try to decide well.
9/30/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
What is one thing you are very confident about?
Do you think your confidence is JUSTIFIED?
Voluntarism: having a choice about something
All advice presupposes voluntarism
Rational voluntarism: One OUGHT to be rational
What, exactly, is it to be rational?
Doxastic voluntarism: What you believe is a matter of choice
2+2=5
Eric Sotnak owns a 2020 Honda Accord
2+2=4
Kant: “’Ought’ implies ‘can.’”
You ought to believe rationally
Is doxastic voluntarism true?
Obstinate/willful belief.
(Belief perseverance.)
One ought to be rational.
Why?
Beliefs are action-guiding.
And true beliefs guide actions better than false beliefs.
What, exactly, is it to be rational?
Believing for one kind of reasons rather than others.
Beliefs can be justified/motivated rationally or not depending on the nature of the reasons.
Rationality doesn’t appear to involve believing on the basis of desires, but rather on the basis of OBJECTIVE CONSIDERATIONS. These considerations make the belief MORE LIKELY TO BE TRUE than others (that would call irrational or non-rational).
Rationality is truth-enhancing.
What, exactly, is truth?
What, exactly, is a belief?
A belief is true if and only if the belief corresponds to the facts. (Correspondence theory)
The belief ‘x’ is true if and only if x.
Truth is a property of beliefs (or of statements, claims, propositions, representations).
A belief is a representation (or model) of how things are.
To belief rationally is for one’s belief to be supported by the totality of one’s available information.
Generally speaking, information I provides support for a belief B when I makes B more likely to be true.
What, exactly, is information?
Information consists of data that is capable of being described or creates a representation (a model).
When information can be used to make an inference to a belief, we say that the information is evidence for the belief.
10/2/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
Some people have endorsed the following principle:
“You don’t really know something unless you can explain HOW you know it.”
Do you agree or disagree with this?
Problem of the criterion:
In order to know something, you have to know what the conditions are for knowing it.
Similar:
You can’t know something unless you know that you know it.
What, exactly, is it to believe something?
To believe a proposition is to adopt an attitude of uncoerced acceptance toward it (to assent to it). If someone asks you whether you think it is true, you will sincerely say ‘yes.’
Does belief come in degrees?
Whether or not it does, depends on how one conceives the relation between acceptance and confidence, and how much importance one places on common linguistic practices.
Traditional account of belief distinguishes three doxastic attitudes:
For any proposition that you consider you can:
a) Believe it
b) Disbelieve it
c) Suspend judgment about it
So:
If a claim is supported by one’s total evidence, one should believe it. If a claim is undermined by one’s total evidence, one should disbelieve it. And if one’s total evidence is neutral with respect to a claim, one should suspend judgment about it.
What is the difference between opinion and knowledge?
Socrates (knowing how/why one knows)
Plato
Senses: confused
Forms: clear (grasp the principle behind the belief)
(Logos = Form)
Aristotle
Episteme (scientia) – necessity, universality
Techne
Sophia (theoretical wisdom)
Phronesis (practical wisdom)
<insert scientific revolution here>
Infallibilism: Knowledge =
Complete absence of possible reasons for doubt
Objective Impossibility of error
Rene Descartes
Omnipotent God
Skepticism
Restricted: There are very few things that can be known
Unrestricted: There is nothing that can be known
Unrestricted skepticism appears contradictory because if it is true, then it cannot be known that it is true (it cannot be known that there is nothing that can be known).
“Master argument” for skepticism:
1. For any way that things appear to be, there are multiple possible explanations for why things appear to be that way.
2. There is no way to know with certainty which of these possible explanations is correct.
3. Therefore, there is no way to know with certainty why things appear the way they do.
This kind of skeptical argument motivates a problem that we can find in almost any philosophical tradition in history that can be called ‘the appearance-reality gap.’
Problem with infallibilism:
Practically unsustainable
Fallibilism: (1) We can be in a position to CLAIM knowledge even where we are less than perfectly certain. (We can be in a position to think we know even if we really don’t.) (2) Justification doesn’t have to be perfect; it only has to be good enough (for practical purposes and the common use of ‘know’). (3) If we gain new information that our belief really is in error, we can change our minds.
Why fallibilism?
“ordinary language” approach to philosophy
(Wittgenstein: “meaning is use”)
(Note that the definition of ‘fallibilism’ uses ‘knowledge’. What is knowledge on the fallibilist view?)
The JTB account of knowledge:
S knows that P if and only if the following conditions all obtain:
1. S believes that P is true
2. P is in fact true (you can’t know something that is false)
3. S is adequately justified in believing that P is true
What, exactly, is adequate justification?
“Reasonable person standard”: S is adequately justified in claiming to know P if the average person would accept that S knows P on the basis of S’s justification.
10/7/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
Can you think of a time when you had an “I was right after all!” experience?
In 1963, Edmund Gettier published a very short paper whose influence has far exceeded its length.
“The Gettier Problem”
The paper presents two counterexamples to the JTB analysis of knowledge.
Gettier’s case rests on the possibility of describing situations where a person’ belief is true, and their reasons would normally be “good enough” (justified) but in the case at issue the belief is in some sense only accidentally true (or true merely by luck).
Edmund Gettier’s counterexamples:
- Suppose that Smith and Jones have both applied for a job.
- Smith has very strong evidence that Jones will get the job (suppose he overheard the company president say that the job will go to Jones).
- Smith also saw Jones give someone a dollar bill in exchange for ten dimes, which he then put in his pocket.
- Smith therefore is justified in believing that Jones will get the job, and that Jones has ten coins in his pocket.
- Smith therefore has strong justification for believing that the man who will get the job has ten coins in his pocket.
- But suppose that Smith is the man who will get the job (the company president had mixed up the names of Smith and Jones).
- Suppose, also, that Smith happens to have ten coins in his pocket, though he in unaware of this.
- So, it is true that the man who will get the job has ten coins in his pocket.
- Smith’s belief that the man who will get the job has ten coins in his pocket is justified, and it is true, but it seems wrong to say that Smith knows that the man who will get the job has ten coins in his pocket, since his belief is about Jones, who will not get the job.
(Trick that makes this work is ‘generalization’)
Gettier’s 2nd counterexample.
It is a truth of logic that if a statement A is true, then so is any proposition that has the form “A or B” (no matter what B is). [This is called the rule of addition in formal logic]
- Suppose Smith has strong justification for believing that Jones owns a Ford (he has seen Jones driving a Ford, wearing a “proud Ford owner” t-shirt...)
- Smith doesn’t know where Jones is, and thinks to himself, “maybe Jones is in Boston, of all places”.
- Smith thinks about the logical rule of addition, and thinks to himself, “well, at least I can know that either Jones owns a Ford or Jones is in Boston”.
- Suppose that Jones does not own a Ford after all (the car he has been seen driving is rented, and he bought the shirt at a garage sale for $0.25).
- Suppose, also, that by sheer coincidence Jones is in Boston.
- So, the statement “Either Jones owns a Ford or Jones is in Boston” is true, because Jones is in Boston.
- So, Smith’s belief is justified, and it is true, but it seems wrong to say that Smith knows that “either Jones owns a Ford or Jones is in Boston” is true.
(Trick is the ‘rule of addition’)
One of the first objections to Gettier’s paper highlighted the fact that in both of his examples, the person has a false belief that serves as the basis of the final true belief:
- Jones has 10 coins in his pocket.
- Jones owns a Ford.
It seems easy to fix JTB as follows:
S knows that P if and only if:
1. S believes that P is true.
2. P is in fact true.
3. S is adequately justified in believing that P is true.
4. S’s belief that P is not based on some other belief of S’s that is false.
But it didn’t take long for people to come up with examples showing this won’t work.
Here is my own example of a “Gettier case”:
- Suppose I buy a box of cookies and put them in my desk drawer.
- At 9:00 I leave my desk.
- At 9:01, Zeke steals the cookies from my desk drawer.
- Zelda sees this.
- At 9:02, Zeke leaves his desk.
- At 9:03, Zelda takes the cookies from Zeke’s desk and puts them back in my desk.
- At 9:10 I return to my desk and think to myself, “There is a box of cookies in my desk drawer.”
- My belief is true. There IS a box of cookies in my desk drawer. I am justified in believing this. My reasons for believing it are good enough for fallibilism.
- But it doesn’t seem that I know there are cookies in my desk, because I don’t know about the theft and replacement of the cookies. (My belief is only true because I got lucky in how things turned out.)
Another example:
(This is a realistic fake sheep)
- Ferd buys 100 fake life-sized sheep and puts them out in his field.
- Ferd’s neighbor, Gerd has a flock of real sheep.
- One day, one of Gerd’s sheep wanders into Ferd’s field.
- Herd is out walking, looks into Ferd’s field, and sees Gerd’s sheep.
- Herd believes he is looking at a live sheep.
- Herd’s belief is true, and his reasons for believing it are good enough for fallibilism.
- But it doesn’t seem Herd knows he is looking at a real sheep (his chances of looking at a real sheep are only 1 in 101 – his belief turned out to be true only by luck).
It is common for people to overlook the fact that a counterexample to the JTB analysis requires that the belief the person holds has to actually be true as well as justified. It doesn’t work if someone holds a justified belief that is actually false.
Despite the difficulties of Gettier cases, few philosophers advocate returning to infallibilism.
It seems that there is an easy fix which is just to add that S’s belief can’t be accidentally true:
S knows that P if and only if:
1. S believes that P.
2. P is true.
3. S is justified in believing P.
4. S’s belief that P is not true only by accident (or luck).
But it is unclear what being “true only by accident” means.
If a waiter drops a tray and I witness it, I believe the waiter has dropped a tray, it’s true, I’m justified, but isn’t it only true by accident?
Well, that’s not what “accidentally true” means, right?
But then what DOES it mean?
Suppose that in the cookie theft case, Zelda plans to steal Zeke’s cookies, but is deterred by the fact that Zoe is near Zeke’s desk (which is very unusual for her). My cookie belief (Zeke has cookies in his desk today) is true only by virtue of good luck.
Or:
Delbert has excellent evidence that the Earth is round. But Delbert irrationally becomes persuaded of a conspiracy theory that the Earth is flat. One day when playing baseball, Delbert is hit in the head by a wild pitch which damages his ability to believe conspiracy theories, so he now believes the Earth is round. But isn’t this only by accident/luck?
10/9/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
Do you agree with the following?
“It is wrong, always, everywhere, and for everyone, to believe anything upon insufficient evidence." (William Clifford)
What, exactly, does ‘wrong’ mean in Clifford’s maxim?
The most natural interpretation is that Clifford thinks it is morally wrong to believe upon insufficient evidence. (This is also supported by Clifford’s examples.)
Internalism: The view that evidence is internal to the believer (it is what is in a person’s mind/memory… what is cognitively accessible).
Externalism: Evidence is a matter of what a person has access to in the world (not just in their minds).
Here is an argument to support Clifford:
1. If belief B1 guides action better than belief B2, then it is wrong to believe B2.
2. True beliefs guide actions better than false beliefs.
3. Beliefs supported by sufficient evidence are much more likely to be true than beliefs that are not.
4. Therefore, it is wrong to hold beliefs upon insufficient evidence.
To refute Clifford, it suffices to come up with a counterexample showing one case where it is NOT wrong to believe something on insufficient evidence.
Counterexamples don’t have to be ACTUAL.
(Why not?)
Which of these numbers do you think I’m thinking of?
| 83 | 47 | 65 | 91 |
| 52 | 78 | 14 | 66 |
| 39 | 88 | 73 | 54 |
| 27 | 95 | 61 | 42 |
Suppose you believe that I’m thinking of the number you picked.
Are you wrong for believing this?
Irrational, yes.
But no plausible moral principle is violated by this case.
Even if Clifford’s claim is too strong, most people sympathize with the claim that, in some sense, one OUGHT to be rational.
The term for this is ‘epistemic obligation.’
Some have rejected epistemic obligations on the grounds that it presupposes doxastic voluntarism.
Does it?
Can prudential considerations justify belief?
- “Believe in yourself”
- Medical risk (medical option with small chance of success)
- Relationship trust
- Pascal’s Wager (and similar)
[discuss]
Remember this:
If belief B1 guides action better than belief B2, then it is wrong to believe B2. (One ought to believe B1, instead.)
It is true that beliefs are action-guiding.
But it is a mistake to think that ONLY beliefs are action-guiding.
Feelings are also action-guiding.
Is it always wrong to be guided by beliefs than by feelings?
Some have tried to suggest that feelings can always be expressed in terms of beliefs.
“Schlick trick”
“It is wrong, always, everywhere, and for everyone, to believe anything upon insufficient evidence."
What is the evidence for this?
10/14/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
What’s an example of a dumb thing to do?
(Bonus if it’s something you’ve actually done.)
There are two basic types of reasoning: Deductive and inductive.
Deductive reasoning is based on logical relations that make “perfect inferences” possible. An inference connects the premises of an argument to a conclusion (The conclusion is inferred from the premises). In a deductive inference, IF the premises are true, the conclusion MUST also be true (purely as a function of how logic works).
Example:
1. Maureen plays Bridge every Tuesday.
2. Today is Tuesday.
3. Maureen plays Bridge today.
Inductive reasoning: In an inductive inference, if the premises are true, the conclusion is PROBABLY true.
Example:
1. Maureen has played Bridge every Tuesday for the past 20 years.
2. Today is Tuesday.
3. Maureen will play Bridge today.
Basic rule of inductive inference is: The future will continue to resemble the past.
David Hume (1711-1776)
Empiricism: All knowledge derived from experience.
Divided knowledge into:
1. Relations of ideas
2. Matters of fact
Relations of ideas are known to be true by definition or analysis (analytic truths/statements)(a priori truths)
- All vixens are female.
- All triangles have three sides.
- Anyone born in Nebraska is a US citizen.
Matters of fact are only known to be true by experience (synthetic truths/statements)(a posteriori truths)
- Some bananas are purple.
- My son has blue eyes.
- Triceratopses are extinct.
- Water freezes at 0 degrees C.
What is the status of the following two claims?
(1) Every event must have a cause. (Universal causation.)
(2) The same causes must always produce the same effects. (Causal uniformity.)
What, exactly, is causation?
How, exactly, does causation work?
Causation is a relational concept: Nothing is a cause except insofar as it relates to an effect. Nothing is an effect except insofar as it relates to a cause.
Is every event necessarily either a cause or an effect?
Neither of these are true by definition or analysis – they are not analytic truths.
So, they must be synthetic truths – known by experience.
But what, exactly, do we experience?
Suppose I light one candle.
1. This candle burns when lit.
2. Therefore, all candles will burn when lit.
I cross my fingers before scratching off a lottery ticket.
1. I won money after crossing my fingers.
2. Therefore, I will always win money after crossing my fingers.
Why is my inference good with candles, but not with scratch off tickets?
That is, some things happen in the world as a result of what we call laws of nature while others are just happenstance.
Correlation is not always causation.
Coincidence is not causation.
There is a difference between science and superstition. (The former is grounded in causation, the latter in coincidence (or fear).)
But how do we know/think the difference?
What, exactly, is a cause?
Cause-effect idea:
- Spatial & temporal proximity (cause & effect are close together in space and time)
- Temporal asymmetry of cause-effect (causes always come before effects)
- *Necessary connection (causes and effects are necessarily connected)
Hume suggests the following argument:
1. Laws of nature are not analytic truths. (relations of ideas)
2. But necessary truths can only be analytic.
3. Therefore, laws of nature are not necessary truths.
Hume says the connection between cause and effect is not logically necessary.
It is always possible to conceive/imagine any two causally connected events occurring separately.
If some event is conceivable without contradiction, then it is possible.
If causes and effects are not logically connected (logically necessary), then what OTHER type of connection can there be?
Can there be another kind of necessity than logical necessity? (Physical necessity.)
Where COULD the idea of physical necessity come from in experience?
So how do we learn such connections?
Ivan Pavlov
10/16/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
A popular definition of insanity is doing the same thing while expecting different results. Have you ever been guilty of this?
(Bonus if you can give a
specific example.)
Hume says we learn cause-effect relations by “custom” (or habit).
Hume claims that the connection between cause and effect isn’t really necessary. It just FEELS necessary to us because our minds have been habituated to connect them.
There seems to be, for Hume, no difference between BEING causally necessary and FEELING causally necessary.
This seems to imply that causal beliefs are somehow not RATIONAL.
(This poses an obvious threat to science. (Major motivation for later philosophy (in particular, Immanuel Kant).))
A possible response to the apparent skepticism of Hume’s analysis of causation is to hold that causal beliefs are not DEDUCTIVELY rational, but they are INDUCTIVELY rational.
Deductive reasoning depends on logical structures that are defined in certain ways.
Consider the argument:
1. Either Wilma or Betty is the winner.
2. Wilma is not the winner.
3. Therefore, Betty is the winner.
If we ask how we know that deductive reasoning is reliable, the answer is that once we understand how deductive reasoning works, we understand that it HAS TO work.
Inductive reasoning is different, though.
Consider the argument:
1. All the ravens I’ve ever seen are black.
2. Therefore, all ravens are black.
The general form of this argument is:
1. All the x I’ve ever seen are y.
2. Therefore, all x are y.
Clearly, the form of this argument doesn’t make it so that “all x are y” has to be true.
It’s the nature of inductive reasoning that it is fallible. (Another point in favor of fallibilism.)
But the question remains as to why inductive reasoning is ever any good to begin with.
At the heart of inductive reasoning is this claim:
The future will resemble the past.
Is this necessarily true? No.
So, it is only known by experience. How do we know it?
Answer: Because in the past, the future has turned out to resemble the past.
To put it another way:
There is no deductive argument that inductive reasoning is reliable.
The argument for the reliability of inductive reasoning relies on inductive reasoning. Which is circular reasoning.
The problem Hume identifies here has been called The Problem of (the justification of) Induction.
In brief: Inductive reasoning cannot be deductively justified and can’t be inductively justified without presupposing that inductive reasoning is justified.
Is circular reasoning bad?
(For purposes of explanation, yes. “X because X” doesn’t really explain anything.)
The problem of induction is puzzling, but not necessarily all that worrisome.
There are other cases where one needs/uses X in order to do X.
Here are two examples from computer science:
Self-hosting: It is possible for compilers or interpreters to be written in the same language they compile or interpret (for example, an implementation of Python can be written in Python).
Recursive functions: Some functions can call themselves as part of their procedure.
Example:
def factorial(n):
if n == 0 or n == 1:
return 1
else: return n * factorial(n - 1)
Another example is that it is impossible to give a definition of ‘language’ that isn’t given in language.
Suppose we accept that inductive inference is reliable (as it seems we should).
That is, we can, in good conscience, accept that:
The future will continue to resemble the past.
Nelson Goodman suggests that we still have a problem.
Imagine that one day space aliens land on Earth in search of emeralds.
Because emeralds have the most beautiful color – “grue”.
In the alien language, “grue” means “green if observed before 1/1/2026 and blue thereafter.”
They also like sapphires, because sapphires are “bleen” – blue if observed prior to 1/1/2026 and green thereafter.
As an Earthling, you believe that all emeralds are green, and all sapphires are blue.
The alien believes that all emeralds are grue and all sapphires are bleen.
But (since 1/1/2026 isn’t here yet) you and the alien have exactly the same inductive evidence for the claims:
(A) All emeralds are green.
(B) All emeralds are grue.
You say, “All the emeralds I’ve observed in the past have been green, so inductive reasoning tells me that all the emeralds I observe in the future (including after 1/1/2026) will also be green.”
The alien says, “All the emeralds I’ve observed in the past have been grue, so inductive reasoning tells me that all the emeralds I observe in the future (including after 1/1/2026) will also be grue.”
You say, “But that’s crazy, because if an emerald is grue, it will change color from green to blue on 1/1/2026.”
The alien responds, “No, you’re the one who is crazy, because if an emerald is green, it will change color from grue to bleen on 1/1/2026.”
Goodman’s point is that the rule “the future will resemble the past” doesn’t help unless we can answer the question of what, exactly, it means for the future to resemble the past.
If all emeralds really are grue, then if emeralds all change from green to blue on 1/1/2026, then the future will turn out to have resembled the past in respect of grue -ness, but if they don’t change from green to blue on 1/1/2026, then the future will turn out to have resembled the past in respect of green -ness.
Whether the future resembles the past or not is not just a function of inductive reasoning, but also of the concepts we apply to things in the first place.
We think the concepts we use are “correct” and the concepts the alien uses are “weird.” But what determines that this is true?
Most people think the grue problem is just an intellectual curiosity. But it actually has important and far-reaching implications because it forces us to ask whether our concepts are the only or right ones.
How do we know our concepts are the best model for reality?
Representationalism: We don’t perceive the world directly. Rather, our perceptions involve filters from our senses, but also from our language, concepts, …
Important application: Data ontologies
What is a correct description of something?
What is the correct way to distinguish things from one another? (What, exactly, is a THING?)
What criteria can/should we use to describe conditions?
Example: Suppose I am designing an app that connects to my phone.
What different ways could I determine what “my phone” is for the app?
10/21/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
Do you believe animals have souls?
History of the concept of the soul
What is the soul supposed to do?
2 primary functions concepts of soul were intended to perform:
- Explain life (difference between living and non-living things) = vitalism (soul = principle of life): something needs to be added to a body to have life
- Explain cognition/consciousness/reason
Today, no one in the sciences accepts vitalism
The view that the soul explains (or is need to explain cognition) is now generally called “dualism”
Rene Descartes argues that the mind/soul is a distinct substance from the body (and can exist without it):
- Substance dualism
- Interactionist dualism
- Cartesian dualism
- Mind-body dualism
What are the arguments for mind-body dualism?
Main type of argument:
Argument from divergent properties:
1. The mind has properties that the body doesn’t have (or vice versa), i.e., they have divergent properties.
2. If x and y have divergent properties, then x and y can’t be the same.
3. Therefore, the mind is not the same as the body.
Shift from mechanics to function
The discovery of the electro-chemical nature of the brain shifts focus away from mechanics
The invention of electronic computing (electro-mechanical switches)
A neuron and the basic components of computers work in the same basic way:
Computers are based on on-off switches
Brains are based on firing-nonfiring neurons
What is the mind?
Dualism (substance dualism): mind = a non-physical entity (=soul) that associates with the body/brain but is distinct from it
Main arguments for dualism:
- Divergent properties arguments (minds and brains/bodies have divergent properties)
- Appeal to religious belief (non-rational)
- Appeal to paranormal experiences
Identity theory: mind = functioning brain, or rather, every mental state JUST IS a brain state
- Progress in brain science
Functionalism: mind is a function of a brain or analogous information-processing system
(“The mind is what the brain does.” – Marvin Minsky)
- Thought experiments
- Progress in artificial intelligence
Both identity theory and functionalism are physicalist: (they are consistent with the thesis that only physical things exist)
10/23/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
Are you able to form mental images (pictures)?
What, exactly, is the mind?
Three main theories of mind:
- Dualism – the mind is a thing in its own right that interacts with the body/brain and is necessary in order to perform certain cognitive operations (reason, grasping universals, abstracting, understanding, consciousness, free will, …)(mind, soul, spirit, self)
- Identity theory (every mental state is identical to a brain state)(Mind = set of mental states)(Most extreme version = eliminative materialism)
- Functionalism (mental states are functional states of material systems)
Descartes: The foundation of knowledge is INTROSPECTION.
The dominant view after Descartes is that to think is to have IDEAS.
Representational theory of mind/cognition.
Tho think is to have ideas.
After Newton, science becomes primarily about observation and measurement.
Can there be a SCIENCE of Psychology? (Some have thought not)
The mind appears to be unobservable as an object of scientific study.
One approach is to rely entirely on self-reports.
For example:
How could I possibly verify your experience?
There are often good reasons to reject self-reports.
Here is an example. If you think you are a 1 or a 2 on the above aphantasia test, picture a pine tree.
Now, count the number of branches on the tree.
Could you count the needles?
Is there anything behind the tree?
Is the tree in dirt? Grass? Does it have roots?
What kind of light is illuminating the tree? Are any of the branches in shadow?
These questions suggest that picturing a tree is different from looking at one, because the mental image is constructed, and the construction process is updated when trying to answer the questions.
What, exactly, is a mental image?
What, exactly, is an idea?
Behaviorism in psychology: We can’t know the inner contents of minds.
We can’t observe thoughts, intentions, beliefs, or feelings.
We can only know what we can observe: behavior. (Mind as “black box”) Stimulus & response are the only proper variables for a science of psychology.
Behaviorism in philosophy: We can’t know minds directly. We can only know inputs and outputs. But ALSO: If we can’t empirically confirm a statement, it is meaningless (logical positivism). So, terms like “mind” turn out to be meaningless.
Early AI holds that to think is to give the “right” sorts of outputs in response to the “right” sorts of inputs.
10/28/2025
[Philosophy Club every Tuesday at 5:00pm in CAS 436 ("The Cave")]
[Challenge for today: Try to think of (and possibly ask) at least one question.]
Do you think animals can feel pain?
If the mind is not observable, then what criteria determine whether or not someone or something is thinking?
Behaviorist approaches say it can only be behavior. If something acts like it is thinking, we have to say that it is.
Of course, “acts like” must be construed broadly.
Turing Test: If a computer gives the same kinds of outputs in response to inputs as a human being, then the same reasons I say the human is intelligent should make me concede that the computer is intelligent.
Multiple realizability (the same function can be performed by different things – sometimes radically different)
Input-output (or “black box”) functionalism (standard view in traditional AI):
To be intelligent is to give the “right kinds” of outputs in response to the right kinds of inputs
(Intelligence/thought/cognition must be defined operationally) (relates to “the problem of other minds”)
If a machine/animal/other system behaves in operationally relevantly similar ways to me when I am thinking, then it must also be thinking. (Cognitive equivalence = behavioral equivalence)
The internal details are irrelevant because there can be different ways of doing the same thing. (multiple realizability)
Is artificial intelligence real intelligence?
LLMs can now (mostly) pass the Turing Test
Does this mean they think?
Do they understand?
Me: “What makes a movie scary?”
ChatGPT: “Excellent question — and one that horror directors, psychologists, and audiences have been debating for a century. There’s no single formula, but truly scary movies usually tap into both biological reflexes (what startles us) and psychological vulnerabilities (what disturbs us).”
Does ChatGPT understand what “scary” means?
Horizontal vs. vertical understanding
(syntactic vs semantic meaning)
Somewhere around the 1980s attitudes in philosophy of mind began to shift away from functionalism and behaviorism in particular.
Shift represents a return to the reality of the subjective.
“Eliminative materialism” is the view that terms like “belief” “feeling” need to be eliminated from a scientific description of mind/behavior/cognition, ….
These terms operate like the term “sunset.”
On the introspective account, we should always know what we believe, feel, etc.
But do we?
Two figures in philosophy that represent the turn back toward the subjective are Frank Jackson and Thomas Nagel
Both emphasize the ineliminability of the subjective
Nagel: “What is it like to be a bat?”
The phenomenon of consciousness can only be understood from the subjective point of view.
This means that reductionist and eliminativist programs, including functionalism, are wrong.
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