How to Argue - Induction & Abduction: Crash Course Philosophy #3

Summary

This Crash Course Philosophy episode explores inductive and abductive reasoning, essential tools in philosophy and everyday life. Inductive reasoning predicts future events based on past patterns, though it offers no certainty. Abduction, or inference to the best explanation, involves eliminating impossible scenarios to arrive at the most plausible conclusion. The episode also discusses the Socratic method, emphasizing the pursuit of truth over winning arguments, and introduces the concept of counterarguments in philosophical discourse.

Takeaways

• 🧠 Induction is a method of reasoning that relies on the predictability of nature, using past experiences to predict future outcomes.
• 💊 The example of aspirin illustrates inductive reasoning, where past effectiveness is used to predict future relief from headaches.
• 🎬 Inductive reasoning can also apply to non-scientific matters, such as predicting enjoyment of a new Marvel movie based on past experiences.
• 🔮 Unlike deductive reasoning, which provides certainty, inductive reasoning only offers probabilities and potential for false results.
• 🤔 The problem of induction is highlighted by the potential for the future to differ from the past, as patterns can have exceptions.
• 💎 Nelson Goodman's 'grue' thought experiment demonstrates the potential flaws in inductive reasoning by showing contradictory conclusions.
• 🕵️‍♂️ Abduction, or 'inference to the best explanation,' is a reasoning method that involves eliminating impossible explanations to find the most plausible one.
• 🧩 Abduction is useful in situations where there is incomplete or unclear evidence, such as medical diagnosis or detective work.
• 📚 The Socratic method involves a dialogue between interlocutors, where counterarguments are used to refine and strengthen beliefs towards the truth.
• 🏆 Philosophical arguments aim not to 'win' but to discover truth, with counterarguments serving as a tool for eliminating falsehoods.
• 🌐 Squarespace is highlighted as a sponsor, offering easy website creation for sharing passions and ideas without the need for coding.

Q & A

What is the main focus of the Crash Course Philosophy episode discussed in the transcript?

The main focus of the episode is on the types of philosophical reasoning, specifically inductive and abductive reasoning, and how they are used to make predictions and arguments in philosophy and everyday life.

How does the script define inductive reasoning?

Inductive reasoning is defined as a method that relies on the predictability of nature to suggest that the future is likely to resemble the past, often in important ways. It works in terms of probabilities and does not provide certainty but rather likelihood of being true.

What is an example of inductive reasoning provided in the script?

An example given is the belief that aspirin will cure a headache because countless aspirin tablets have cured countless headaches in the past.

What is the difference between deductive and inductive reasoning as per the script?

Deductive reasoning provides certain answers based on general information leading to a specific conclusion, often something that is kind of obvious. In contrast, inductive reasoning starts with specific observations and makes broader generalizations or predictions about the future.

What is the problem with inductive reasoning as highlighted in the script?

The problem with inductive reasoning is that it does not guarantee accurate results because the future does not always resemble the past, and every pattern has its outliers, leading to the potential for false conclusions.

Can you explain the concept of 'grue' introduced by Nelson Goodman as per the script?

The concept of 'grue' is a thought experiment by Nelson Goodman to illustrate the problems of induction. Gruesome objects are green before a certain time 't' and blue after it. It demonstrates how inductive reasoning can lead to contradictory conclusions based on the same evidence.

What is abduction as described in the script?

Abduction, also known as 'inference to the best explanation,' is a reasoning process that involves eliminating possible explanations until the most plausible one is left, given the evidence at hand. It does not provide certainty but is useful for puzzling situations with unclear evidence.

How does the script relate abduction to Sherlock Holmes?

The script quotes Sherlock Holmes from 'The Sign of the Four' who said, 'When you have eliminated the impossible, whatever remains, however improbable, must be the truth.' This is an example of abduction, where the most plausible explanation is chosen after ruling out the impossible ones.

What is a counterargument according to the script?

A counterargument is an argument offered in opposition to another argument. It is used in philosophical discussions to challenge a conclusion and is part of the process of refining beliefs and getting closer to the truth.

What is the Socratic method and how does it relate to philosophical arguments?

The Socratic method is a form of dialogue popularized by Socrates that aims to bring interlocutors closer to the truth through the exchange of ideas and arguments. It is not about winning but about finding truth, and counterarguments are seen as a way to refine beliefs rather than defeat an opponent.

How does the script describe the role of counterarguments in philosophical discussions?

The script describes counterarguments as essential to philosophical discussions. They are used to challenge conclusions and refine beliefs. A good philosopher appreciates a counterargument that they cannot respond to, as it helps them reject false beliefs and build stronger ones.

Outlines

00:00

🧠 Inductive and Deductive Reasoning in Philosophy

This paragraph introduces the concepts of inductive and deductive reasoning, highlighting their importance in everyday life and philosophy. Inductive reasoning is based on the predictability of nature and the idea that the future is likely to resemble the past, as exemplified by the common use of aspirin for headaches and the anticipation of enjoying a new Marvel movie based on past experiences. Deductive reasoning, while certain, often relies on general information to reach a specific and perhaps obvious conclusion. The paragraph emphasizes the need for additional reasoning methods beyond deduction, such as induction, to make predictions and rule out impossibilities, which are crucial for developing skillful arguments in philosophy.

05:02

🕵️‍♂️ Abductive Reasoning and the Philosophical Exchange

The second paragraph delves into abductive reasoning, also known as 'inference to the best explanation,' which involves eliminating possible explanations until the most plausible one remains, given the evidence. Examples provided include a student dropping a physics class and a case of food poisoning potentially caused by sushi. This method of reasoning is contrasted with deductive and inductive reasoning, with the latter being probabilistic and the former not guaranteeing certainty. The paragraph also discusses the Socratic method of philosophical dialogue, where the goal is to arrive at the truth through reasoned argument and counterargument, rather than to simply 'win' a debate. The importance of counterarguments and the collaborative pursuit of truth in philosophical discussions are highlighted, along with the role of abduction in everyday reasoning, such as in diagnosing illnesses or solving crimes.

Keywords

💡Induction

Induction is a method of reasoning that involves drawing general conclusions from specific observations. It is central to the video's theme as it is used to explain how we make predictions about the future based on past experiences. For example, the script mentions that because many aspirin tablets have cured headaches in the past, we predict that a current aspirin tablet will cure a headache.

💡Deductive reasoning

Deductive reasoning is a form of logic where conclusions are drawn from one or more general premises. It is contrasted with inductive reasoning in the script to highlight that while deductive arguments provide certainty, they often deal with information that is already known and somewhat obvious, unlike induction which deals with probabilities and the unknown.

💡Aspirin

Aspirin is used in the script as a practical example of inductive reasoning. It is a medication known for its pain-relieving properties, and the script uses the predictability of aspirin's effect to illustrate how we use past experiences to anticipate its effect on a headache.

💡Abduction

Abduction, also known as 'inference to the best explanation,' is a form of reasoning that involves making the best plausible explanation from available evidence. The script introduces this concept as a way to approach situations where there is no clear evidence, using the example of a student's absence from class to infer that they dropped the course.

💡Counterargument

A counterargument is an argument presented in opposition to another argument. The script discusses counterarguments in the context of philosophical discourse, emphasizing that they should be used to refine beliefs and get closer to the truth rather than to 'win' a debate.

💡Socratic method

The Socratic method is a form of dialogue used to stimulate critical thinking and to illuminate ideas. It was popularized by Socrates and involves asking and answering questions. The script mentions this method as a way of exchanging ideas in philosophy, where the goal is to discover truth rather than to defeat an opponent.

💡Inference

Inference is the process of deriving logical conclusions from premises known or assumed to be true. The script discusses different types of inferences, such as inductive and abductive, as they relate to the process of reasoning and forming conclusions.

💡Grue

The concept of 'grue' is introduced in the script as a thought experiment by philosopher Nelson Goodman to illustrate the potential flaws in inductive reasoning. Gruesome objects are green before a certain time and blue afterward, challenging the predictability of induction.

💡Truth

Truth is a central theme in the script, particularly in the context of philosophical reasoning and the pursuit of knowledge. The script emphasizes that the goal of philosophical argumentation is to find truth, not to win an argument.

💡Sherlock Holmes

Sherlock Holmes is referenced in the script as an example of a character who uses abductive reasoning to solve mysteries. His famous quote about eliminating the impossible to find the truth is used to illustrate the concept of abduction.

💡Interlocutor

An interlocutor is a person involved in a dialogue or conversation. The script uses this term to describe the participants in a philosophical exchange, where each party either advances an argument or offers a counterargument.

Highlights

Inductive reasoning is essential for predicting future events based on past experiences.

Deductive arguments provide certainty but are limited by the need for general information to reach specific conclusions.

Philosophy and life require reasoning beyond deductive logic to account for the unpredictability of the world.

Induction uses past experiences to make predictions about the future, but does not guarantee certainty.

The effectiveness of aspirin for headaches is an example of inductive reasoning based on research and personal experience.

Inductive reasoning can lead to false conclusions because it only provides likelihood, not certainty.

Nelson Goodman's grue thought experiment highlights the potential flaws in inductive reasoning.

Abduction, or inference to the best explanation, is a reasoning process that eliminates impossible explanations to find the most plausible one.

Abduction is used in situations where clear evidence is lacking, such as in medical diagnosis and detective work.

The Socratic method, popularized by Socrates, involves a dialogue to bring interlocutors closer to the truth rather than winning an argument.

Counterarguments are essential in philosophical discourse, allowing for the refinement of beliefs and arguments.

Philosophers engage in argumentation with higher standards, focusing on the strength of reasoning rather than personal preferences.

The goal of philosophical argumentation is to find truth, not to defeat an opponent.

The transcript discusses the practical applications of different reasoning methods in everyday life and philosophical inquiry.

The episode is sponsored by Squarespace, emphasizing the platform's ease of use for creating professional websites without coding.

Crash Course Philosophy is produced in collaboration with PBS Digital Studios, showcasing a variety of educational content.

The importance of reasoning techniques in forming arguments and counterarguments in the philosophical discourse is underscored.

Transcripts

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How do you know that aspirin will take care of your headache?

Why do you really want to see the new Marvel movie, even though you haven’t heard anything about it, good or bad?

Your ability to do things like predict how a medication will affect you, or what movie

you might like, or even things like what the perfect gift might be for your best friend,

or what’s the fastest way to get to campus –- all of this stuff, you know through induction.

Deductive arguments are great because they give us certain answers.

But unfortunately, much of the world cannot be summed up in a neat deductive proof.

Deduction requires a fair amount of general information to give you a specific conclusion

that is, frankly, probably kind of obvious.

So, philosophy -- and basically, you know, life as well -- require that you have other ways of reasoning.

In addition to knowing how one fact leads to another, you also need to take what you’ve

experienced before, and use that to predict what might happen in the future.

And you need to be able to rule out what can’t be true, so you can focus on what can.

Through these kinds of reasoning, you’re not only able to figure out stuff like how

to fix your headache, and why your roommate might be acting weird. You can also come up

with better, more skillful arguments — and counterarguments — which are some of the

most important maneuvers in the philosophical game.

And maybe the best part is, you already know how to use these techniques.

In fact, I bet you’ve used them this very day. You know this!

[Theme Music]

If you possess any ability to really predict the future, it lies in your ability to reason inductively.

Inductive reasoning relies on the predictability of nature to reveal that the future is likely

to resemble the past, often in important ways.

For example, there’s tons of research to support the knowledge that aspirin -- acetylsalicylic

acid -- is an effective treatment for pain, like headaches.

And you probably have personal experience with the effects of aspirin, too.

So, you believe that this aspirin tablet will cure the headache you have right now, because

countless aspirin tablets have cured countless headaches in the past.

Likewise, you want to see the new Marvel movie, because you liked most of the other ones,

so you believe that they’ll continue to deliver for you, entertainment-wise.

But it’s important to remember that, unlike deduction, where true premises entail true

conclusions, inductive premises only mean that the conclusion is likely to be true.

Inductive arguments don’t provide you with certainty. Instead, they work in terms of probabilities.

And they’re useful for more than predicting what’s going to happen. For example:

Most men in ancient Athens had beards. Socrates was a man who lived in ancient Athens.

Therefore, Socrates probably had a beard

This is an inductive argument, because it starts with what we already know – about

the grooming habits of ancient Athenian men, and about the time and place in which Socrates

lived – and makes an educated guess based on that information.

There’s no guarantee that the conclusion is correct, but what’s known would seem to support it.

Reasoning like this is incredibly useful, which is why it’s so common. But there’s also a problem.

The future doesn’t always resemble the past. And every pattern has its outliers.

So induction always has the potential to produce false results. Aspirin might not work on a

really bad headache. The new Marvel movie might be awful. And, yeah, maybe a specific

guy in Athens had a beard but it’s possible he didn’t!

While the world tends to work according to predictable rules, sometimes those rules are violated.

And you know what you need when that happens? A little Flash Philosophy. Off to the Thought Bubble.

Contemporary American philosopher Nelson Goodman confronts the problems of induction, using

a thought exercise about a hypothetical substance called grue.

According to Goodman’s scenario, grue is anything that’s the color green before a

certain time, a time that we will call t.

And another property of grue is that, while it’s green before time t, it’s blue after it.

Now, let’s assume that we’re living in a time before t. T could happen a hundred

years from now or tomorrow, but we know that all of the emeralds we’ve ever seen are green

So, inductive reasoning lets us conclude that all emeralds are green, and will remain green

after time t -- since emeralds haven’t been known to change color.

BUT! All emeralds are grue! Because it's not yet time t, and they're green, which is part of the definition of grue.

So we have no choice but to conclude that the emeralds will be blue after time t arrives.

Now we’ve got a problem. Because inductive reasoning has led us to conclude that emeralds

will be blue after time t, but inductive reasoning also tells us that they’ll remain green.

Goodman’s riddle reminds us that inductive evidence can be flawed, or contradictory.

It can make you think that you can predict the future, when of course you can’t.

So, there are times when you need to get at the truth in other ways. Like by eliminating

what’s obviously not true, and considering what’s most likely.

And for this, we turn our attention to one of the most important philosophical figures

of 19th century England: Sherlock Holmes.

In chapter six of Sir Arthur Conan Doyle’s “The Sign of the Four,” Mr. Holmes says, and I quote:

“When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

This is probably the best, most succinct description ever given of the kind of reasoning known as abduction.

Which I know, it sounds like we’re talking about a kidnapping or something, but abduction

is a thought process sometimes described as “inference to the best explanation.“

Abduction doesn’t reason straight from a premise to a conclusion, as we’ve seen in deduction and induction.

Instead, it reasons by ruling out possible explanations until you’re left with the

most plausible one, given the evidence. Consider this:

Anna told you she failed her physics midterm.

Anna hasn’t been in physics class since your teacher graded the exams.

Anna has been in sociology class, which meets right after physics.

Anna dropped physics.

Now, with only these premises, we can’t deductively or inductively prove our conclusion

– that she dropped physics.

But, it’s a justifiable conclusion, because, given what we know, dropping the class is

the most plausible explanation of events.

We know she’s not sick – because she’s still going to sociology – and we know she

had good reason to withdraw from the class, because she was unlikely to pass.

Concluding that she dropped the course makes the most tidy use of our information, without

leaving any loose ends. So let’s look at another one:

You and your roommate ate sushi last night.

You both wake up with violent stomachaches.

You and your roommate ate some bad sushi.

The mere fact that you’re both sick doesn’t prove that the sushi caused the sickness.

But, given that you both ate the same thing and you both have the same symptoms – absent

other information, like that a stomach virus is going around your dorm – the best explanation

is that the sushi caused your intestinal anguish.

Now, like induction, abduction doesn’t give us certainty.

But it is a really useful way to get through puzzling situations when you don’t have

clear evidence from the past to help you out.

Doctors use abduction a lot when they’re diagnosing illnesses, and detectives of course

use it when piecing together evidence.

You probably use it pretty often too – just beware, because abduction must be used carefully!

It uses only information you have at hand -- that’s why doctors and detectives work

so hard to dig up more data, and re-create events from the past, so they can help draw better conclusions.

All right, now that we’ve looked at some argument types, let’s find out how philosophers

use arguments to interact with each other.

Because, philosophers don’t argue like other people do.

It’s not like the conversation you have around the dinner table about whether the

Patriots are better than the Seahawks, or why plain M&Ms are superior to peanut, which

is clearly a preposterous position to take.

Philosophers hold each other to different, higher standards.

They don’t teach each other get away with saying, “I reject your argument because

I don’t like its conclusion.” Or, “That’s preposterous, peanut M&Ms are so good.”

Instead, if you disagree with a conclusion, you need to give reasons, just like the first

person did when they made their case.

Both people involved in this kind of exchange are known as interlocutors, because we have

to name everything. The first one advances an argument, and the second one can either

accept it, or offer a counterargument, which is just what it sounds like – an argument

offered in opposition to another argument.

Think back to Socrates and the beard.

You think Socrates had a beard, and your reasoning is that most men in his time and place had them.

I, however, think you’re wrong. So I give you a counterargument.

Gorgias, a contemporary of Socrates, said Socrates couldn’t grow a beard and that

he would sneak into barbershops and steal discarded clippings to fashion fake beards

for himself. Therefore, Socrates didn’t have a (real) beard.

And I just want to point out that this is an actual philosophy conspiracy theory.

Gorgias was a real guy, who differed with Socrates on many things, and the dispute was

said to have gotten personal.

According to accounts of the time, Gorgias actually spread the rumor that Socrates wore,

like, a beard-wig, in an effort to shame and discredit his rival. I mean, how could you

be a good thinker if you weren’t a good beard-grower.

Gorgias’ gossip didn’t go over well with everyone, and in this instance, let’s say

you are skeptical about it too.

So you counter my counterargument with a counter-counterargument.

Gorgias was known for being a gossip, and for hating Socrates, and trying to make him

look bad. His fake beard tale seems wildly unlikely. Therefore, we can’t take Gorgias’

statement seriously, so we should fall back on the best information we have, which is

that most of the men in his time and place had beards.

And as you can see, arguments of different styles can be used in the same exchange.

Like, the original argument, about Socrates probably having a beard, was inductive.

But this last counterargument is abductive. And that’s fine.

Arguments are meant to be useful, so we don’t have to use the same kind of reasoning when we argue.

This way of exchanging ideas through dialogue was popularized by Socrates, and so has become

known as the Socratic method.

Socrates thought dialogue was the best way to learn, and to get at truth.

And it’s important to note that, while philosophers have a reputation for being an argumentative

lot, they don’t think of the Socratic method as something that results in a winner and a loser.

Rather, it’s an exercise that brings both interlocutors closer to the truth.

The goal of the philosopher is not to win, but to find truth, so you shouldn’t be disappointed

if someone presents a counterargument that you can’t find a response to.

When that happens, a good philosopher will be grateful to their interlocutor for helping

them reject false beliefs and build stronger ones.

Today you learned about two more types of philosophical reasoning, induction and abduction.

You’ve seen their strengths, and their weaknesses. And you’ve also learned about counterarguments,

and the Socratic method.

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