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Notes on video lecture:
How We Know Things
Choose from these words to fill the blanks below:
evolutionary, permanence, deductions, suspicion, exist, thinking, nothing, cause, inference, snack, errors, false, battery, equally, prove, others, doubt, logical, assertions, how, few, difficult, claimant, simulation, vat, scientific, certain, placebo
to know if something is true, we need to know        we know what we know
this is actually a                    question
has a massive literature in philosophy
what do we mean by knowledge
justified true beliefs
from very early philosophy people have been skeptical that we can know anything at all
Socrates: "I know one thing: that I know               ."
to get around this problem, René Descartes, tried to prove what it was that one could actually            that one knows
how do you show that you indeed know something
"I know that I exist because I'm                 "
it could be that you are a brain in a       
you could be dreaming
we might all be in a computer                      set up by a society of the future trying to figure out how things might have gone differently
you can't show any of this for               
in theory, as a Cartesian skeptic, you realize you know very        things about the world, e.g. that you exist because you think and 1+1=2
in practice, however, you don't want to be a Cartesian skeptic, because it would be very difficult to live life if you doubted everything               , e.g. that the food you eat or the floor you walk on is not real
and if you don't want be a Cartesian skeptic, you need to understand that we know what we know based on evidence we have for different                     , and how strong that evidence needs to be depends on the reason we need this particular piece of information, e.g.
to make a traffic stop requires reasonable                   
to make an arrest requires probably           
to convict someone of a crime requires evidence that is beyond a reasonable           
five key types of evidence
1. proof
anything that can be determined through mathematical or                reasoning
a. logical proofs
since thinking imples existence, since I am thinking, I know that I           
b. mathematical proofs
1+1=2
2. claims
statements we have heard or read from             
examples
New York is American's largest city (true)
It takes seven years to digest gum. (          )
three things to evaluate claims
a. plausibility
is it relatively likely
b. expertise of the                 
to what extent does the person who made the claim have the ability to know what they are claiming
e.g. is the explanation of how a root canal is performed coming from your dentist or a friend
c. reliability of the claimant
how accurate as the source been in the past
how often has the source admitted and correct              in the past
3. experience
things we have watched or directly encountered
compare to claim which are indirect
examples
it hurts to touch hot things
John ate lunch at noon
reliability of observations
maybe John was not eating lunch but was having a            and ate lunch later
consider any optical illusions
4. inference
extensions that we make from other evidence
examples
object                     
babies think objects go in and out of existence depending on if they are currently experiencing them
                         theory
making the logical step from observed evidence such as the fossil record to explain what has happened in the past
John likes pizza because I saw him eating pizza
quality depends on
quality of evidence
how big the leap of                    is
how many times did you see Tom eat pizza
5. deductive testing
the                      method
the most systematic way we have of gaining information
we make a hypothesis, set up a test, and have numerous people who doubt the results test it
examples of hypotheses to test
acetaminophen outperforms a               
get two groups and give them both
the Earth goes around the Sun
gather information about how planets, stars, and Sun moves around in the sky and make                     
the television is not broken
make sure it is plugged in
make sure the remote control has a               
make sure the battery is not dead
quality of testing
how rigorously was the scientific method adhered to

Ideas and Concepts:

How to avoid Cartesian skepticism via tonight's Fake News and Alternative Facts class:

"To know if something is true, we need to know how we know what we know. But when you begin to think about and research how we know what we know, this turns out to be a quite difficult question that has a massive literature in philosophy.

Generally by knowledge, we mean justified true beliefs. But since very early philosophy, people have been skeptical that we cannot justifiably know anything at all. Socrates, for instance, argued quite convincingly that he could know nothing for certain except that he knows nothing for certain.

To get around this problem, René Descartes tried to prove what it was that one could actually prove that one knows. His conclusion was that he could prove that he knows he exists because he was thinking, but this really isn't useful when you consider that you can't even know for certain that your world you live in is even real, since you could be a brain in a vat, or you could be dreaming, or we might all be in a computer simulation set up by a society of the future trying to figure out how things might have gone differently. You can't show any of this is not the case for certain.

In theory, we logically have to be Cartesian skeptics, and can only know for certain that e.g. something exists, that we are thinking, and that certain mathematical statements such as 1+1=2 are certain by definition, but any other statement that is made, we cannot be certain of.

In practice, however, you don't want to be a Cartesian skeptic, because it would be very difficult to live your life sanely if you doubted everything equally, e.g. that the food you eat was safe, or the floor you walk on was real.

And if you don't want be a Cartesian skeptic, you need to understand that we know what we know based on evidence we have for different assertions, and how strong that evidence needs to be, depends on the reason we need to know this particular piece of information.

For instance, for a traffic cop to make a traffic stop requires reasonable suspicion, for a police officer to make an arrest requires probably cause, and for a court to convict someone of a crime requires evidence that is beyond a reasonable doubt.

This is just the beginning of how we can claim we know what we know, and by respecting the various degrees of evidence that are required to know that various statements about the world are true to various degrees, will show you that we can indeed know quite a bit about the world, and quite accurately."
The kinds of evidence that help us determine the extent to which what we know about the world is true, via this morning's Fake News and Alternative Facts class:

"In our constant analysis of what we think is true in our world and what is not and to what degree, there are five key types of evidence we use:

1. PROOF:Anything that can be determined through mathematical or logical reasoning

This includes (a) logical proofs, e.g. since thinking implies existence, since I am thinking, I know that I exist, and (b) mathematical proofs e.g. 1 + 1 = 2.

2. CLAIMS:Statements we have heard or read from others

For example, we might read that New York is American's largest city, which can be shown to be true, or we may hear from a friend that it takes seven years to digest gum, which can be shown to be false.

To evaluate claims, we consider (a) PLAUSIBILITY, e.g. the more experienced and educated you become, the less plausible stories about UFO abductions, bigfoot sightings, miracle cures, and get-rich-quick schemes seem to you, (b) EXPERTISE OF THE CLAIMANT, e.g. to what extent the person who makes the claim has the ability to know what they are claiming, so the explanation of how a root canal is performed coming from your dentist is more reliable than from a friend who is not a dentist, and (c) RELIABILITY OF THE CLAIMANT, e.g. how accurate has the source been in the past, so if someone makes claims which you point out to have fallacies and contradictions, and they regularly ignore these attacks on their argument, you tend to trust what they say less in the future.

3. EXPERIENCE:things we have watched or directly encountered

Examples of evidence from experience is (a) that it hurts to touch hot things, or (b) John ate lunch at noon.

While experience is more direct and therefore usually more accurate than claims, we still need to consider the reliability of own observations, e.g. it may be true that even though we saw John eating lunch, that he was not eating lunch at all, but was having a snack and then ate lunch later. And we need to learn about the numerous kinds of optical illusions and other deficiencies of our brains especially in incidents of high emotion, we often have memories which can be shown to be wrong, e.g. what clothes a person was wearing or what color hair they had.

4. INFERENCE:extensions that we make from other evidence

Examples are (a) OBJECT PERMANENCE, i.e. that even though we can't see an object anymore, we assume it is still there and will be there if we go look for it again, (b) EVOLUTIONARY THEORY, i.e. making the logical step from observed evidence such as the fossil record to explain what has happened in the past, (c) JOHN LIKES PIZZA which we say we know since we saw him eating pizza.

The quality of our inference depends on the quality of evidence and how large the leap of inference is, e.g. how many fossils have been found or how many times did you see Tom eat pizza.

5. DEDUCTIVE TESTING, often referred to as the scientific method

This is the most systematic way we have of gaining information:We make a hypothesis, set up a test, and have numerous people who doubt the hypothesis perform the test with the intention of proving it wrong.

Examples of hypotheses that we test are, (a) ACETAMINOPHEN OUTPERFORMS A PLACEBO, for which we get two groups and give them each a different pill and record their experiences, (b) THE EARTH GOES AROUND THE SUN, in which we gather information about how planets, stars, and Sun moves around in the sky and make deductions based on these observations, then make predictions and observations to see how accurate our predictions are based on our hypotheses, and (c) THE TELEVISION IS NOT BROKEN, which try to prove by checking if it is plugged in, by checking that the remote control has a battery, and by checking that the battery is not dead.

The quality of our deductive reasoning depends on the amount of rigor involved in applying the scientific method."
How We Know Things
Democratic News Consumption: The Ideal and the Reality
The Definition of Propaganda and Fake News
Seven Types of Inaccurate News
How News Has Changed
Accuracy in the Digital Era