How to Argue - Philosophical Reasoning: Crash Course Philosophy #2

Summary

This Crash Course Philosophy episode explores the concept of rationality as a defining human trait, contrasting it with irrationality often seen in everyday arguments. It delves into Plato's tripartite soul theory, highlighting the rational, spirited, and appetitive aspects of the human psyche. The episode uses Bertrand Russell's barber paradox to emphasize the importance of sound reasoning and introduces deductive arguments, illustrating how premises must lead to a valid conclusion to ensure logical consistency and truth.

Takeaways

• 🧠 Aristotle considered rationality as the defining characteristic of humans, setting them apart from animals.
• 🤔 Despite the potential for irrationality, people can often be persuaded by logical arguments, highlighting the importance of reason.
• 🗣️ Arguments are a common tool for persuasion, used in everyday life, but often lack the structured logic that philosophers employ.
• 📚 Learning about arguments and reasoning can enhance one's persuasive abilities and make one a more convincing communicator.
• 📚📚 The script introduces the concept of a 'tripartite soul' by Plato, dividing the human psyche into rational, spirited, and appetitive parts.
• 🧐 Plato believed that the rational part of the soul should govern, and that those ruled by spirited or appetitive aspects are less human.
• 🤝 Modern philosophy agrees with Plato that reason should govern, even if the concept of the tripartite soul is not universally accepted.
• 💭 The script uses thought experiments and puzzles to test and improve reasoning skills, as favored by philosophers.
• 🪒 Bertrand Russell's barber paradox is presented to illustrate the importance of self-consistency in logical groups and reasoning.
• 📉 An argument in philosophy is structured by premises that support a conclusion, with deductive arguments being a key type.
• 🔍 Deductive arguments are valid when the truth of the premises guarantees the truth of the conclusion, but validity does not equate to the truth of the premises.
• 📚 The script emphasizes the value of sound reasoning and the pursuit of valid and sound arguments for clear and effective communication.

Q & A

What did Aristotle describe humans as, and how does the script interpret this description?

Aristotle described humans as 'the rational animal.' The script interprets this by explaining that rationality is our distinguishing characteristic, setting us apart from other animals, and that despite disagreements, people can generally be persuaded by arguments.

Why does the script suggest that most people are not good at arguments?

The script suggests that most people are not good at arguments because they often confuse making a good argument with having witty comebacks or shouting louder, rather than building a case on a solid foundation of logic.

What is the significance of learning about arguments and strong reasoning according to the script?

Learning about arguments and strong reasoning is significant because it not only makes one a better philosopher but also sets one up to be a more persuasive person, someone who is convincing and whose opinions are more likely to be listened to.

What is Plato's concept of the tripartite soul, as mentioned in the script?

Plato's concept of the tripartite soul divides the human psyche into three parts: the rational part, which seeks truth and is swayed by facts and arguments; the spirited part, which is about emotions and actions driven by feelings; and the appetitive part, which is shared with animals and drives basic desires and self-preservation.

How does the script describe the difference between the rational, spirited, and appetitive parts of the soul?

The rational part is associated with cool reason and truth-seeking. The spirited part is about emotions that fuel actions, such as righteous anger and ambition. The appetitive part is about basic desires like eating and protecting oneself, driven by temptations.

What is the barber paradox presented by Bertrand Russell, and what does it illustrate?

The barber paradox is a thought experiment where a town's barber shaves only those who do not shave themselves. The paradox questions whether the barber shaves himself, leading to a logical contradiction. It illustrates that a group must always be a member of itself, and if the logic behind a group's existence doesn't hold, then the group cannot exist.

What is the main rule of deductive arguments as described in the script?

The main rule of deductive arguments is that if the premises are true, then the conclusion must also be true. This type of reasoning is called entailment.

How does the script differentiate between a valid argument and a sound argument?

A valid argument is one where if the premises are true, the conclusion cannot be false. A sound argument, however, is not only valid but also has all true premises, guaranteeing the truth of the conclusion.

What is the difference between validity and truth as it pertains to arguments?

Validity refers to the logical structure of an argument, ensuring that if the premises are true, the conclusion must also be true. Truth, on the other hand, refers to the actual correctness of the premises and conclusion. An argument can be valid but have a false conclusion if the premises are not true.

Why are deductive truths usually not very surprising, according to the script?

Deductive truths are usually not surprising because they start with known, true premises and lead to conclusions that are logically entailed by those premises. They do not typically lead to new or startling information.

What is the script's final point about the importance of reason and argument structure?

The script concludes by emphasizing the value of reason and the importance of understanding the structure of arguments, particularly deductive reasoning, to ensure that one's beliefs are backed by sound premises and valid reasoning.

Outlines

00:00

🤔 The Nature of Rationality and Argumentation

This paragraph delves into the concept of rationality as a defining human trait, as Aristotle suggested, and contrasts it with the common occurrence of irrational behavior in everyday arguments. It highlights the importance of logical argumentation in persuading others, rather than relying on emotional outbursts or wit. The paragraph introduces the idea that understanding and mastering the art of argumentation can enhance one's ability to be persuasive and convincing. It also sets the stage for a discussion on the historical development of reason, starting with Plato's tripartite soul theory, which differentiates between the rational, spirited, and appetitive aspects of the human psyche. The paragraph concludes with a thought experiment by Bertrand Russell to illustrate the complexities and potential paradoxes that can arise from flawed reasoning.

05:01

📚 The Structure and Types of Arguments in Philosophy

The second paragraph provides an in-depth exploration of philosophical arguments, emphasizing the need for sound reasoning supported by premises. It distinguishes between various types of arguments, with a focus on deductive arguments, which are structured to guarantee the truth of the conclusion if the premises are true. The paragraph explains the concept of entailment and validity in deductive reasoning, using the example of Socrates' mortality to illustrate a valid argument. It also clarifies the difference between a valid argument and one that is both valid and sound, highlighting the importance of having true premises. The discussion extends to the limitations of deductive reasoning, noting its reliance on certain premises, which are not always readily available. The paragraph concludes by setting the stage for further exploration of other types of arguments in future discussions.

Keywords

💡Rationality

Rationality refers to the ability to think logically and make decisions based on reason. In the script, it is presented as a defining human characteristic that distinguishes us from animals, as Aristotle suggested. The theme of the video revolves around the importance of rationality in argumentation and decision-making, emphasizing that despite moments of irrationality, humans generally have the capacity to be persuaded by logical arguments.

💡Argument

An argument, in the context of this video, is a set of statements or claims intended to persuade or convince others to believe or do something. The script discusses how people often engage in arguments without adhering to logical structures, contrasting common misconceptions with the philosophical approach to constructing a solid and persuasive argument.

💡Tripartite Soul

The tripartite soul is a concept introduced by Plato, dividing the human psyche into three parts: the rational, spirited, and appetitive. The script uses this concept to explain the different motivational aspects of human behavior, illustrating how the rational part should ideally govern the other two, aligning with the video's theme of the supremacy of reason.

💡Deductive Argument

A deductive argument is a type of logical reasoning where the conclusion is necessarily true if the premises are true. The script provides an example of a deductive argument with the classic 'All humans are mortal' scenario, highlighting the importance of validity and soundness in reasoning, which is central to the video's exploration of rational argument construction.

💡Entailment

Entailment in logic refers to the relationship between statements where the truth of one requires the truth of another. The script explains this concept using the deductive argument about Socrates' mortality, illustrating how one fact necessitates another within a valid argument, which is key to the video's educational goal of teaching sound reasoning.

💡Validity

Validity in the context of arguments means that if the premises are true, the conclusion must also be true. The script clarifies the difference between a valid argument and one with a true conclusion, using examples to show that an argument can be valid without being sound if its premises are false, which is crucial for understanding the structure of logical arguments.

💡Soundness

Soundness in logic is achieved when an argument is both valid and all its premises are true, ensuring the conclusion is also true. The script emphasizes the goal of constructing sound arguments as the epitome of rationality, which is integral to the video's message on the value of reason.

💡Premise

A premise is a statement or proposition that forms the basis of an argument, providing evidence for the conclusion. The script dissects the anatomy of an argument, explaining that premises are the building blocks that support the conclusion, and their truth is essential for the argument's validity.

💡Conclusion

The conclusion is the final statement or result of an argument, which follows logically from the premises. The script uses the deductive argument example to show how the conclusion about Socrates' mortality is derived from the premises about human mortality, illustrating the role of the conclusion in the structure of an argument.

💡Barber Paradox

The Barber Paradox, introduced by Bertrand Russell, is a thought experiment presented in the script to illustrate logical self-reference and the limitations of certain types of reasoning. It challenges the viewer to consider whether the barber shaves himself, a question that leads to a logical impasse, thereby demonstrating the importance of coherent and non-contradictory reasoning.

💡Persuasion

Persuasion is the act of convincing someone to believe or do something through argument or evidence. The script suggests that learning about arguments and strong reasoning can make one a more persuasive person, which ties into the video's overarching theme of the power and value of rational discourse.

Highlights

Aristotle described humans as 'the rational animal', emphasizing rationality as a distinguishing characteristic.

People can often be persuaded by arguments, highlighting the importance of rational discourse.

Arguments are used in everyday life, not just in philosophical discussions.

The common mistake of confusing a good argument with loud or witty responses.

Learning about arguments and reasoning can enhance persuasive abilities.

Introduction to Plato's concept of a tripartite soul, dividing the self into rational, spirited, and appetitive parts.

The rational part of the soul seeks truth and is swayed by facts and arguments.

The spirited soul is linked to emotions and actions, responding to righteousness and ambition.

The appetitive part is shared with animals, driven by basic desires and temptations.

Plato believed the best humans are ruled by their rational soul, keeping other parts in check.

Modern philosophy agrees that reason should guide our actions, despite not fully adopting the tripartite soul concept.

Flash Philosophy introduces thought experiments to test reasoning skills.

Bertrand Russell's barber paradox illustrates logical inconsistencies and the importance of self-membership in groups.

The anatomy of an argument includes premises that support a conclusion.

Deductive arguments require that if premises are true, the conclusion must also be true.

Deductive reasoning starts with general premises and reasons to a specific conclusion.

The difference between a valid argument and a sound argument, with sound arguments being both valid and based on true premises.

The limitations of deductive reasoning due to the rarity of having only true premises.

The value of deductive reasoning for providing certainty, despite its limitations.

The episode concludes with an introduction to Squarespace and other Crash Course productions.

Transcripts

Crash Course Philosophy is brought to you by Squarespace.

Squarespace: share your passion with the world.

Aristotle once described humans as “the rational animal.”

Well, actually, he said that “man is the rational animal,” but we don’t have to

be sexist just because he was.

And if you’ve ever gotten into an argument with someone about religion or politics or which

Hemsworth is the hottest, then you’ve experienced how irrational people can be about their opinions.

But what Aristotle meant is that rationality is our distinguishing characteristic – it’s

what sets us apart from the beasts.

And no matter how much you disagree with someone about God or Obama or Chris Hemsworth, you

can at least grant that they are not beasts.

Because, most of the time at least, people can be persuaded. By arguments.

You use arguments all the time -- in the comments, at family dinners, with your friends -- you

probably just don’t think of them the same way that philosophers do.

When you try and convince your parents to loan you the car, or when you’re talking

up Crash Course to your friends, you are using arguments. Thanks, by the way.

Each time you tell someone to do or believe something -- or when you’re explaining why

you do or believe something -- you are giving an argument.

The problem is, the vast majority of people aren’t really good at arguments.

We tend to confuse making a good argument with, like, having witty comebacks, or just

making your points more loudly and angrily, instead of building a case on a solid foundation

of logic. Which can be harder than it sounds.

But learning about arguments and strong reasoning will not only make you a better philosopher,

it will also set you up to be a more persuasive person. Someone who people will listen to.

Someone who’s convincing.

So, yeah, these skills are beneficial no matter what you want to do with your life.

So you might as well know how to argue properly.

[Theme Music]

If you want to learn how to argue, then you should probably start about 2400 years ago,

when Plato was laying out how reason can, and should, function in the human mind.

He believed that we all have what he called a tripartite soul – what you might think

of as your “self,” or your psyche, divided into three parts.

First, there’s the rational, or logical part of the soul, which represents cool reason.

This is the aspect of your self that seeks the truth and is swayed by facts and arguments.

When you decide to stop eating bacon for two meals a day because, as delicious as it is,

it’s bad for you, then you make that decision with the guidance of the rational part of your soul.

But then there’s the spirited aspect, often described as the emotional part of the self,

although that doesn’t really quite capture it.

The spirited soul isn’t just about feeling -- it’s also about how your feelings fuel your actions.

It’s the part that responds in righteous anger at injustice, the part that drives your

ambition, and calls upon you to protect others.

It gives you a sense of honor and duty, and is swayed by sympathy.

So if you decide to stop eating bacon because you just finished reading Charlotte’s Web,

and now you’re in love with Wilbur, then you’re being guided by the spirited part of your soul.

But we share the next part of our soul with other animals, be they pig, or moose, or aardvark.

The appetitive part is what drives you to eat, have sex, and protect yourself from danger.

It is swayed by temptations that are carnal, and visceral.

So at those times when you go ahead and just EAT ALL THE BACON because it just smells so

dang good, the appetitive aspect of your soul is in control.

Now, Plato believed that the best human beings -- and I should point out here that Plato

most definitely did believe that some people were better than others -- are always ruled

by the rational part of their soul, because it works to keep the spirited and the appetitive parts in check.

People who allow themselves to be ruled by their spirited or appetitive selves are base,

he believed, and not fully, properly human.

Now, most of us don’t buy into the concept of the tripartite soul anymore -- or the idea

that some humans are less human than others.

But we do understand that we’re all motivated by physical desires, emotional impulses, and rational arguments.

And philosophers continue to agree with Plato that reason should be in the driver’s seat.

So, how do you know if you’re good at it? How can you test your reasoning?

Well, let’s head over to the Thought Bubble for some Flash Philosophy.

Throughout this course, we’re going to apply our philosophical skills by pondering puzzles, paradoxes, and thought experiments.

Because remember: Philosophers love thinking about questions -- especially ones that don’t have ready answers.

So think of these exercises as philosophical wind-sprints -- quick tests of your mental abilities.

And here’s a doozy, from 20th century British thinker Bertrand Russell, one of the pioneers

of what’s known as analytic philosophy.

Say there’s a town in which all men are required by law to be clean-shaven. This town

has only one barber, a man, who must follow strict rules:

Rule number one: He must shave all men who do not shave themselves.

Rule number two: He must not shave any man who does shave himself.

It’s the nightmare of every libertarian and every mustachio’d hipster. But here’s the question:

Does the barber shave himself?

Cause think about it: The barber only shaves men who don’t shave themselves. So if he does

shave himself, then he must not, because the barber’s not allowed to shave guys who shave themselves.

But, if he doesn’t shave himself, then he has to be shaved by the barber, because that’s the law.

Russell came up with this puzzle to illustrate the fact that a group must always be a member of itself.

That means, in this case, that “all men who shave themselves” has to include every

guy who shaves himself, including the barber.

Otherwise, the logic that dictates the group’s existence just doesn’t hold up.

And if the barber is a logical impossibility, then he can’t exist, which means the reasoning

behind his existence is inherently flawed.

And philosophy doesn’t tolerate flawed reasoning.

So, how do we make sure that we’re ruled by good, sound, not-flawed reason?

By perfecting the art of the argument.

An argument, in philosophy, isn’t just a shouting match.

Instead, philosophers maintain that your beliefs should always be backed up by reasons,

which we call premises.

Premises form the structure of your argument. They offer evidence for your belief, and you

can have as many premises as you like, as long as they support your conclusion, which

is the thing that you actually believe.

So, let’s dissect the anatomy of an argument.

There are actually several different species of arguments. Probably the most familiar,

and the easiest to carry out, is the deductive argument.

The main rule of a deductive arguments is: if your premises are true, then your conclusion must be true.

And knowing that something is actually true is very rare, and awesome.

So, here’s a boiled-down version of a good deductive argument:

Premise 1: All humans are mortal.

Premise 2: Socrates is a human.

Conclusion: Socrates is mortal.

This kind of reasoning, where one fact leads to another, is called entailment.

Once we know that all humans are mortal, and that Socrates is a human, those facts entail that Socrates is mortal.

Deduction begins with the general – in this case, what we know about human mortality – and

reasons down to the specific – Socrates in particular.

What’s great about deductive arguments is that the truth of the premises must lead to

the truth of the conclusion.

When this happens, we say that the argument is valid – there’s just no way for the

conclusion to be false if the premises are true.

Now check out this argument:

All humans are mortal. Socrates is a human. Therefore, Socrates was Plato’s teacher

That argument is invalid, because nothing about human mortality can prove that Socrates was Plato’s teacher.

As you might have noticed, there are plenty of mortal humans who never taught Plato.

What’s interesting, though, is that this argument does happen to have a true conclusion,

which leads us to another issue. And that is:

Validity is not the same as truth.

All ‘valid’ really means is that if the premises are true, then your conclusion can’t be false.

But that doesn’t mean that your premises prove your conclusion to be correct.

Like, in the case of whether Socrates was Plato’s teacher, the premises are true,

and the conclusion is true, but the argument is still not valid -- because the premises

don’t in any way prove the conclusion. It just happens to be true.

So, if your premises don’t guarantee the truth of your conclusion, then you can end up with some really crappy arguments.

Like this one: - All cats are mammals

- I’m a mammal - Therefore, I’m a cat

As much as part of me would like to be my cat, this is invalid because the conclusion

doesn’t entail from the premises…at all.

I mean, all cats are mammals, but all mammals aren’t cats. Which means there are such

things as non-cat mammals, which I am just one example of.

And it probably goes without saying, but you can have a perfectly valid argument and still have a false

conclusion, if any of your premises are false. For example: - All humans have tails

- My brother John is a human - Therefore, John Green has a tail!

The argument is totally valid! – Because the premises entail the conclusion! The reasoning totally stands up!

It’s just that one of the premises is flawed.

Since I’m reasonably certain that John doesn’t have a tail -- I’ve seen him in a bathing

suit -- this argument is not deductively sound.

And a deductively sound argument is one that’s free of formal flaws or defects.

It’s an argument whose premises are all true, and that’s valid, which means its

conclusion is guaranteed to be true.

So, sound arguments should always be your goal.

The reason that deduction is prized by philosophers -- and lots of other important kinds of thinkers

-- is that it’s the only kind of argument that can give you a real certainty.

But it’s limited, because it only works if you’re starting with known, true premises, which are hard to come by.

And for what it’s worth, deductive truths are usually pretty obvious. They don’t tend

to lead us to startlingly new information, like the fact that I’m not a cat, or that John doesn’t have a tail.

So instead of starting with premises that are already certain, like deduction does,

you’re gonna have to know how to determine the truth of, and your confidence in, your premises.

Which means you’re going to have to acquaint yourself with the other species of arguments,

which we’re gonna do next time.

But today, we talked about the value of reason, the structure of arguments, and we took a

close look at one kind of argument: deductive reasoning.

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