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


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. This episode of Crash Course Philosophy is
made possible by Squarespace. Squarespace is a way to create a website, blog or online
store for you and your ideas. Squarespace features a user-friendly interface, custom
templates and 24/7 customer support. Try Squarespace at squarespace.com/crashcourse for a special
offer. Crash Course Philosophy is produced in association
with PBS Digital Studios. You can head over to their channel to check out amazing shows like The
Art Assignment, The Chatterbox, and Blank on Blank. This episode of Crash Course was filmed in
the Doctor Cheryl C. Kinney Crash Course Studio with the help of all of these amazing people
and our Graphics Team is Thought Cafe.

100 Replies to “How to Argue – Philosophical Reasoning: Crash Course Philosophy #2”

  1. Aristotle's three acts of the mind:
     terms ( clarity , ambiguity )
     judgement ( truth of premises )
    reasoning ( rules of inference )

  2. This should be required viewing followed up by a written test before anyone is even allowed to be on social media.

  3. 'Man' was originally a term that referred to humankind as a whole. No need to find sexism where there isn't any.

  4. But if the group "all men who shaves himself" includes the barber. Doesn't that mean he shouldn't shave himself because of rule 2 of the barbershop rules?

  5. Hey its the sci show guy! This guy is great, I love the emphasis and hand gestures he uses when articulating the finer points of the lesson. I'm always glad to see a video with him in it. Thus I have now subscribed.

  6. Sherlock Holme's version of deduction:

    >Cats have fur.
    >You have fur on you
    >You have a cat.

    Rarely do write him to make more sense like:

    >Endangered cat is missing
    >You have the fur DNA proven to belong to the species
    >You've been around the cat or some one who has.

  7. "But we don't have to be sexist, just because he was." Anyone who starts a discussion on logic and rational vs irrational behavior with such an irrational and juvenile comment should be viewed skeptically, if at all.

  8. The identity of barber is only active when they are barbering. Shaving one's own face isn't barbering and thus it's not a paradox because abstract identities are performative and not inherent characteristics.

  9. Deductive reasoning:

    Premise 1) Batman has black hair
    Premise 2) I have black hair : Invalid
    Conclusion: I am Batman!

    Premise 1) All males have a penis
    Premise 2) I have a penis :Valid and True
    Conclusion: I am a male

  10. 0:14 He is saying Man as in Mankind. Whether Man or woMan. So when you hear Man and automatically think male, YOU'RE being the sexist.

  11. "a group must always be a member of itself" hard to wrap my head around that. I wish it was explained more deeply.

  12. The distortions of facts are unrelenting in this video. Don't watch this unless you want to lose IQ points. It contains several mistakes, on the most basic facts.

  13. "Man" during the time of Aristotle did imply "people" rather than MEN *Exclusive. But, whatever makes your channel adapt to the mainstream.

  14. well at 5:57 it stated that all humans were mortal yet how do you know that all humans are mortal. Have you met all humans? do you know what they know? What is a human? Unless a human is defined as a mortal or if you know all humans now and in the future there is no way to conclude that humans are mortal. So that wouldn't make sense.

  15. Quite a minimalistic approach to argumentation. Maybe looking into Toulmin, McCormick, Aristotle, or even Perelman would give a much more comprehensive insight into what makes a good argument.

  16. I’m good at philosophical reasoning. I win most arguments and end up being right but I’m just learning of philosophy and how it works, heck I don’t even know how to use the word in a sentence so is watching this video gonna help me even tho i know how to argue?

  17. I think I just found the best channel on YouTube..? Mate, your videos are amazing. It's so reassuring (and faith restoring) to see folk like yourself sharing philosophy and inspiring others to embrace it more actively in daily life. Probably one of the single most vital tools for the development of both self and society. Namaste 😊🙏

  18. Even though this is 2019 I love you guys, everything is beautifully said and presented. LOGIC! 😎👐👌🏼

  19. The Barber's paradox is a faulty problem setup, the problem is with point of view. When you set up this reasoning, all men who do not provide the service of shaving to themselves must have it provided for them by the designated third party. In the case of the barber you come to the paradox that he is both client and third party. This is the root of the paradox. When he shaves himself, he is not doing so as the barber, but as himself. The difference here is that self-shaving is a different action then having the shaving be provided for you, being shaved. So if the barber is the only barber, he can only self-shave. He is physically incapable of having someone else do his shaving and have that someone be himself.

  20. الفلسفة كما تعرض هنا غارقة في الجدل والحجج المقبولة وغير المقبولة
    فهي محاولة غالبا لن تنجح في تغيير موقف الخصم
    حتى الجدل الهيجلي الثلاثي يخضع لسطوة التاريخ وأحداثه
    ينبغي أن نتذكر دائما أن الفلسفة طريقة حياة

  21. Believing that some people are better than others doesn't mean that you think they're less human.

    A Chevrolet is no "less car" than a BMW. Fulfills the same funcitions, but it's not wrong to say that one is a better car than the other. Same principle

  22. I wish crash course has a website page where all of their scripts is written into notes , these notes can be useful when u want to skim over the topics.

  23. the barbershop rules says that:
    1. barber must shave all men who do not shave themselves
    2. barber must not shave any man who does shave himself.

    so the barber should shave himself first and the following time he shouldn't right?

    because it says that any man who shave themselves should not be shaved by the barber. but the BARBER HADN'T SHAVED HIMSELF (meaning he still isnt part of the "men who shave themselves") so the second rule still wouldn't be violated. but after he shaved himself( meaning he is now part of the "men who shave himself") he isnt allowed to shave himself coz as the rule says he isn't allowed to shave any man who shave himself

    my own interpretation hehe

  24. Im sorry but is it not obvious that throughout history using the term "men" meant human beings in general. Otherwise we could interpret the scripture that says "It is appointed unto MEN once to die, and then the judgment." really means that the author meant to say that Males will die once but females have many lives. For someone who has made a video attempting to teach philosophy, that seems to me to be an irrational and quick handed attempt to virtue signal by accusing the founders of philosophical thought to be "sexist".

  25. This video makes me think about how flat-earthers probably think that if they argue loudly or angrily enough even with no evidence, they can turn the earth flat. They argue like they want round earthers to turn the earth flat.

  26. It is extremely uncomfortable watching this video, i feel out of breath just watching it. My goodness!!!! Can you shut up for a second? Take a break to breath buddy, There are absolutely no pauses between all those words.

  27. "we don't have to be sexist just because he was"

    Never clicked off of a video so fast. Thank you for the early red flags.

  28. Nice introduction to Western Logic. I was also looking into Indian logic called Pramanas. Both are good stuff.

  29. Haha damn so we starting with an attack on Ariatotle’s character eh? On an episode on how to argue! You cant get any more anti-intellectual than here folks.

  30. A cat that doesn't chase a mouse is less of a cat.
    A human that doesn't feel emotion is less of a human.
    A fish that can walk on the sand is less of a fish.

  31. Calling Aristotle a sexist in the first 20 seconds was stupid. The guy lived 2,000 years ago. I think we can cut him some slack.

  32. What're some of the top books regarding Philosophical Reasoning? Any specific books by Plato in mind? Thanks. loving the videos 🙂

  33. Nitpicking but Aristotle never said "Man is a rational animal.". It was tacit assumption in his theories.

    He said, "man is a political animal" and "man is a social animal."

  34. Question? Why isn't King Solomon consider one of the earliest philosopher? He comes about 504 years before Plato.

  35. "learning about arguments and strong reasoning will not only make you a better philosopher, it'll also set you up to be a more persuasive person"
    I think that this is just optimism. If the people/vast majority is bad at reasoning then why reasoning structurally well would even be something they could be sensible of? In my experience it's almost impossible to get somewhere in any discussion

  36. On the barber paradox, it seems quite easy to solve the puzzle without falling into some existential crisis bs.

    You simply must observe what makes up the reality of what the a barber differs from a simple man and what is the logic behind shaving oneself.

    I had teachers that thought himself of teachers only on the job, just so their students wont annoy them after work, if such is the case, then the barber, when he shaves himself out of his worktime, he is effectively meeting the criteria of the second rule, which is "the barber must not shave any man that shaves himself", if the barber shaves himself during worktime, then he is meeting the criteria for the first rule.

    However, if we think of the job of a barber as a inherent trait permanently carried by the holder of such trait, that it is when it get complex, but it is just a matter of semantics though, people can have aptittude for a barber, but may not be a barber, hence, why the skill =/= being a barber, if the barber trait is in fact something that you can be only named as such if you have the job, then we can conclude once again that the barber shaving himself during worktime or outside of worktime, meets the criteria of one or the other rule,.

    It is deeply complex though, I liked it.

  37. Now let's revisit what Plato said because science has proven that some people are less human than others fact. A Russian scientist discovered that all white people past or present have Neanderthal DNA they were never fully human beings the only full human beings you would ever find came from Africa, therefore some people are less human than others.

  38. @CrashCourse cut the PC please, it's politics, i'm here for knowledge.

    you can't say Aristotle was a sexist, because that would be by today's standards. If he treated women respectfully by the definitions of his own time then he wasn't a sexist, and if those times were sexist by definition, then everybody in that age was a sexist, in which case the mentioning of it is obsolete…
    Ironically the rest of this episode centres around men-based examples… What's wrong with 'women getting a haircut' instead of 'men getting a shave'?
    You disappointed me, CrashCourse

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