Locke, Berkeley, & Empiricism: Crash Course Philosophy #6

Crash Course Philosophy is brought to
you by Squarespace. Squarespace: share your passion with the world. By the time we’re done today, I just might
have you questioning whether this apple is real or not. Think I can’t do it? Gimme
about ten minutes! I might have you wondering whether I’m a physical object or not. And the same goes for all of this stuff, and your
computer, and Nick behind the camera! And … you! How? By unleashing the power of empiricism. [Theme Music] Last time, we learned about 17th century philosopher
Rene Descartes, and how he upended the apple-basket that was his entire personal belief system,
and descended into a radical skepticism, only to emerge with his conviction that: Cogito
ergo sum – I think, therefore I am. This one idea — the fact that he was thinking
— or really, the fact that he was doubting — allowed him to build back up, one by one,
more beliefs that he thought he could rely on. But in the end, most of the beliefs that Descartes
ended up putting back into his intellectual apple-basket had to do with the immaterial
world. Like, he decided that he could believe that
he existed, as a thinking thing. And he believed that God existed. Ultimately, he lit upon the idea that some
of our thoughts are clear and distinct in a way that somehow guarantees their truth. But, a lot of philosophers disagreed. They
argued that thinking on its own wasn’t enough. Like, just because you’re thinking, doesn’t
mean that your thoughts correspond to material reality in any reliable way. Basically, Descartes’ philosophical opponents
thought that the Cogito was a dead end. So here, we start to see a split between two
different understandings of how we can most reliably get to the nature of reality, and
therefore truth. Both were responses to the constant questioning that is skepticism. On
the one hand, there was rationalism. And on the other: empiricism Descartes, like Plato long before him, was a lover of reason. He met skepticism with rationalism. He believed that the most real things in life were ideas — propositions that can be known through pure reason. Deductive truths, which we talked about before,
fall into this category. And mathematical truths do, too. But by contrast, empiricism is based on the
principle that the most reliable source of knowledge isn’t our ideas, or our reasoning,
but our senses. Sure, we can know things through deduction
and basic logic. But what actually leads us to truth, or at
least gives us our best shot at getting there, are things like induction, and the scientific method — ways of thinking that tell us about the material world. Probably the most famous split among philosophers
between these two camps was the life-long debate between Plato and Aristotle. Plato was convinced that Truth resided in
the immaterial world of Ideas, while Aristotle’s attention was focused firmly on the ground. But what about in Descartes’ day? If he
was the original prototype of the navel-gazing philosopher — a living example of rationalist
thinking — then his foil was was the 17th century English thinker John Locke. This is
where he was born. Locke believed that we’re all born as a
tabula rasa, or a blank slate. He argued that all knowledge is
obtained through experience. He rejected the concept of innate ideas — the
view that we’re born pre-loaded with certain information, like what’s good versus what’s
bad, or what is the nature of God. Locke thought that we are born knowing nothing. And instead, all of our knowledge comes
to us through sense data. But one place where Locke agreed with Descartes
was in the idea that, just because your senses tell you something, that doesn’t mean you
can trust it. After all, sometimes your senses give you
false information, like when you think you see or hear something that’s just not there. Descartes’ response to this, of course,
was to just throw out all sense experience as an unreliable source of knowledge. But Locke didn’t go that far. Instead, in
order to figure out whether the senses accurately reflect the outside world, he introduced a
distinction between what he called the primary and secondary qualities of all things. Primary qualities are qualities that physical
objects themselves have. They’re not in our minds, Locke argued — they’re actually
in the stuff. These primary qualities include things like solidity — the density, weight,
and mass of an object. And also extension — the height, depth, and width that a certain
thing has. He also included figure, or the shape of an object, as well as mobility, which
is this – whether it’s stationary or in motion. So primary qualities, Locke said, belong to
the thing itself. Take this apple. It weighs maybe 150 grams,
is the size of my palm, roundish, but firm, with the slightest bit of give, and right
now it’s moving through the air. Those are its primary qualities. But it has secondary qualities, too. And by Locke’s standards, they are not real.
At least not in any objective, agreed-upon way. They’re just in our minds. But they
get there through the primary qualities. I’m talking about things like its color, taste,
texture, smell, and sound. The secondary qualities of this apple are
its redness, and how it tastes and smells and feels on my tongue and hand. Even how
it sounds when I bite into it. Locke believed that the distinction between
primary and secondary qualities explained the disagreements that we all have about our
perceptions of the outside world. Like, we could measure this apple in a bunch
of ways and all agree on its primary qualities, but its secondary qualities would no doubt
lead to some disputes. Like, is it really red? What kind of red exactly?
Cardinal red? Or carmine red? It’s kind of dark purple at the top — or is it just
like a dark pink? What about the sound it made? Would I call that
crunchy? Or crispy? Or…bite-y? It’s like, apple sound. We could argue about that kind of stuff til
the cows came home. But if we disagree about its primary qualities
– one of us is simply wrong. Because primary qualities have nothing to do with you, or me. Instead they have everything to do with the object itself. Locke’s reasoning was simple, even elegant,
extracting a lot of explanatory power out of very few basic concepts. As a result, it
resonated with a lot people. And one person it resonated strongly with
was the Irish philosopher George Berkeley. He was moved by Locke’s empiricism and took
it seriously — so seriously, in fact, that ended up using Locke’s own logic against
him. He basically took empiricism to its logical
conclusion, dismantling the whole process of perception to the point that he had to
wonder whether anything existed at all. Berkeley began by taking apart the distinction that Locke made between primary and secondary qualities. Like, think about this apple again. How do
you know its shape? Locke said that the apple’s shape, as a
primary quality, is immediately perceivable. But Berkeley pointed out that you don’t
perceive some qualities of an object, while totally disregarding others. Like, you can’t
detect an apple’s shape without first — or at least without also — detecting its color.
When you think about it, you can’t detect any of the primary qualities without also
considering the secondary ones. You can’t see a colorless apple.
You can’t feel a textureless apple. In fact, if you try to strip away the apple’s
secondary qualities in an effort to get at the primary ones, you end up with no apple
at all. Try it: Close your eyes and imagine an apple
made of only primary qualities — so, it has a certain shape and a certain size, but it
doesn’t have any color or texture or taste. You can’t do it. You try to imagine it with no color, but really,
you’re probably imagining one that’s either black or white or transparent — the color
of what’s behind it. And if you try to imagine it as having no
texture, you’ll find there’s still a texture there – it’s just smooth. Remember: Locke asserted that secondary qualities
are not objectively real. They can only be subjectively perceived. But now, Berkeley
has shown that the two are inextricably linked – you can’t have one without the other. Which means that primary qualities can’t
be real, either. They, too, are just what your mind makes of things. So this led Berkeley to a startling conclusion:
There’s just no such thing as matter. There can’t be! Instead, there’s only
perceptions. Berkeley’s famous assertion —
his version of cogito ergo sum — was esse est percepi:
“to be is to be perceived.” In his opinion, there are no objects, only
perceivers – and even then, the perceivers themselves don’t really have any physical
form. They’re just disembodied minds perceiving things that aren’t really there. A little bit terrifying when you start thinking
about it. In Berkeley’s scenario, we’re all set
adrift in a world of nothing but thought. What’s scary about it is this, if everything’s
just perception, then when the perception goes away, there can’t be anything left. So like, please, for the love of Pete, do
not turn away from your computer! If you stop perceiving me, I stop existing! But, what if maybe you don’t care about
me? Still, you’d better not go to sleep, because as soon as you do, you’ll cease
to exist! Because, you won’t be able to perceive yourself! The only guarantee that
you’ll continue to exist in your sleep is to have a friend watch you when you’re sleeping. Which probably is a non-starter, for a number of reasons. But in any case, the second your
friend blinks, you’re gone! So in the end, Berkeley believed there was
only one thing that kept us — and everything else — from disappearing into oblivion. God.
Berkeley believed that God was the Ultimate Perceiver. God is always watching, with unblinking perception that holds objects in existence even when we’re not paying attention. The tough thing about Berkeley is, we all
pretty much think he has to be wrong. Very few of us are willing to give up our belief in the physical world — no matter who’s watching. We are sensory animals!
We really need this apple to exist. Next time, we’re going to take a side journey
into the world of knowledge. And then, in episode 8, we’ll see if Karl Popper can
manage to get the physical world back for us. Today we have learned about empiricism as
a response to skepticism. We talked about John Locke and his distinction between primary
and secondary qualities. And we’ve seen why George Berkeley thinks that distinction
ultimately falls apart — leaving us with literally nothing but our minds, ideas, and
perceptions. 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 some amazing shows like Idea Channel, The Art Assignment, and Gross Science This episode of Crash Course was filmed in
the Doctor Cheryl C. Kinney Crash Course Studio with the help of these awesome people and our equally fantastic graphics team is Thought Cafe.

Comments 100

  • I wish there was a term for a person who subscribes to absurdism, existentialism, objectivism, science, rationalism, empiricism, pragmatism, essentialism, relationism, &interactionism…like yes life is inherently meaningless however in order to continue feeling like I want to live I have to navigate systems &objects through interactional means that will be impacted by me while also making an impact on me…and doing so in a way that leads to my own subjectively constructed "purpose/meaning" if you will

  • 0:15 "(You'll question) Nick behind the camera." No I won't because he's not even perceivable so I have no real evidence to support he exists in the first place.

  • Bruh this dude is trash. Stop talking so fast. You are literally mowing over consonants. How tf you not mention Hume either.

  • I hope crash course reads this! (I am so thankful for your educational videos / slight addiction, due to being dyslexic I learn visually and this is the only platform I can learn and take it in) thank you 🙏🏻

  • Damn you a fast speaker

  • 9 minutes of this video summarized my entire 3 month modern philosophy course at the university.

  • Didn't they basically have the same idea then? All of us can perceive, but without perception there's still something. What's the difference between a being that watches everything all the time, so everything keeps existing, and a ''physical world''?

  • If you want to discuss that until a pig is flying, so the case is close. Pink floyd did it

  • Yikes! Hank ate the apple that he threw on the ground… anyone else notice this?

  • I hope you ate all of that apple sir

  • Wait… Berkeley is bunk. Our labels of matter is the perception. That doesn't mean matter doesn't exist. We call color color, but it's still there.

  • Is that a "red delicious" apple? If so, ABSOLUTELY DISGUSTING.

  • I think this Berkeley guy had too much time on his hands.

  • The idea that "knowledge can only be obtained by experiment," could not be obtained by experiment.

  • I wonder what these philosophers would think if they had access to the knowledge of modern science. Atoms, reactions, chemicals, physics etc

  • There is only the occurrence of perception, it's not necessarily that there is a perceiver (that's a false assumption). Buddhism blows these guys out of the water.

  • This video explained Locke's concepts better than Locke does. It feels like Locke's definitions of Primary and Secondary qualities weren't as consistent in "An Essay Concerning Human Understanding".

  • What about micro-organisms that live on us, don't they perceive parts of us thus making us existant? what if it was just the existence of microscopic beings that are what determine we exist as they perceive we exist?

  • Or cart. Gaycart, full of apples

  • Oh my God, this should be aired in Prime time television in Brazil with this war against Philosophy and Sociology.

  • I’ve never enjoyed studying but man I literally just laughed at how someone has to look at while I’m sleeping so I can exist 😂😂😂😂

  • New achievement unlock! New level unlock! Mind blown!Crushcourse listen, im being paying attention about this topic, and i tried to denied everything too and denying how i went a moment ago and the only exist is my thoughts just like this video, i feel good and i feel it why its feels good to meditate, and i tried to experiment something and i know this sounds weird but im planning to think empiricism which my thoughts only exist while masterbating, when seaman went out, i dont feel pain like after the pop and i feel the goodnes but not the same satisfiction as always be , it feels like all are well equal or just fine like not bad or not good just middle of it, weird right , i did bec. I was curious what will happen if i use my body sense to my thoughts. Reply if you did the same expirement

  • You lectures are most rewarding intellectually.

  • It’s like apple sound.

  • I mean… obviously Locke was wrong

  • Isn't the mind, ideas, and perception another perception?

  • 8:22 But how does God exist? Who's perceiving God? That's a fallacy right there Berkeley; you're reasoning is flawed! Get outta here!!!

  • Einstein, for all his brilliance, thought the moon still was up there even while he was not looking at it. Science, hot on the heels of Berkeley and most Eastern philosophy, has proved him wrong. And Locke? Dinosaur favorite of those not brave enough to go all the way.

  • At 5:50 I thought my ipad was dying

  • Hi Guys! Thanks so much for the amazing videos, but can you make a playlist of this Philosophy course, there doesn't appear to be one currently? It's a lot of info to digest in one go, and a lot of hassle to find where I left off the last time without a dedicated playlist. Thanks again!

  • That seems like a really, really nice apple.

  • "If you stop perceiving me, I stop existing" -Hank Green
    Sounds like a good break-up song! 🎵🎶

  • That apple was on the ground, you animal

  • There's just no such things as matter, only perception. Okay perceiving what exactly?

  • Sounds like philosophers spent a lot of time making ridiculous all or nothing claims and as long as they make a new word to go along with it they are somehow validated. Like how people consider themselves flat earthers.

  • is this Schrödinger's cat?

  • This episode might be the dumbest entry of the series lol

  • What an incredible set of videos!! Just wow!! I watched 6 episodes straight, and then just realized I must comment on this amazing course!

  • I love how somebody makes a great conclusion than somebody comes along and just breaks their whole theory down with two questions

  • Descartes

  • Descartes

  • Descartes believed in his thoughts and mind and he believed in God

  • Descartes

  • I did a thought experiment where I died and went to the nether, a sort of hell where there was no sound, light, nor any other things to be sensed. I was swallowed, both me and my bed, at my time of death, starting from the foot of my bed until the world around me was gone. When the mouth closed around me, somewhere past my head, I immediately felt an utter lack of any feeling at all; most terrifying of all, I moved my arms towards my torso to find that it did not exists, nor did my hands nor any other parts of my body. There was no way to mark the passage of time other than the thoughts scrambling around inside my head, and then I remembered that I probably can't think anything when I'm dead, so I gave up and opened my eyes.

  • Berkeley is pronounced "Barkley', BTW. And you might have mentioned Dr Johnson's refutation of Bishop Berkley's insanity, “After we came out of the church, we stood talking for some time together of Bishop Berkeley’s ingenious sophistry to prove the non-existence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it, ‘I refute it thus.'”(Boswell’s Life of Samuel Johnson, quoted from Wikipedia.)

  • I really disagree with the counter argument in this episode. The reason that primary and secondary qualities SEEM to be linked is because we're viewing and talking about them through the very machines that created them in the first place.
    To imagine a world of no secondary qualities is to imagine a world with no life.

    Or let me put it like this: if a tree falls in the forest, does it make a sound? Well sound is a relationship between airwaves and an eardrum. Without the eardrum to sense and interpret the airwaves, they will only stay as airwaves. BUT that does not mean that the tree never existed in the first place

  • I have a question here: He mentioned that deductive and mathematical truths constitute Rationalism, whereas Empiricism is associated with Induction and the Scientific method. However, we use Induction a lot in several mathematical proofs called Mathematical Induction in Statistics (and my area of study – Actuarial Science). Is that an exception or I am missing something?

  • "I think, therefore i am" apparently means a different thing than what i took it for.
    I thought that meant, the things you believe shape who you are independent of what is true or not, apparently not.

  • So, are we living in a simulation (through the use of perfect VR made by an unknown guy we called "God") or not?

  • Thank god we have Google, Facebook and the likes! We are constantly being "perceived" and consequently we exist!

  • Blind people know the shape of an apple that are know it's color

  • So basically god is bacteria as we are always being observed by the millions, billions? Of bacteria around and inside of us

  • Is God the All Seeing Eye?

  • John Locke was on the right track. John Locke had no knowledge about genetics, and how genetic information do, in deed, influence some kinds of behavior. But, in the final analysis: Humans are as maleable as putty. Behaviorists like Pavlov, and B.F. Skinner knew that humans are as trainable as dogs, and as programmable as computers!

  • Nick is definitely not real!!!

  • "Doesn't one need grounds for doubt?" Ludwig Wittgenstein 'On Certainty'

    "It is a mania shared by philosophers of all ages to deny what exists and explain what does not exist" Jean Jacques Rousseau

  • This reminds me of Elder Scrolls lore concerning CHIM, amaranth, and the Godhead.

  • You can easily buy the Cinco sleepwatching chair to watch your friend sleep or any of them with features such as a note taking pad, an electroshock device to keep yourself awake in case of dozing off during the watch and even a system to detect nightmares and prod them.

  • berkeley believed locke so much he practically disregarded him

  • I left school at 14 – my mind was a tabula rasa – so I filled it with info I was interested in

  • Raise your hand if you're uncomfortable and aren't sure if you really have hands to raise

  • u can be Olympic medal winner for fastest speaking

  • Bible says clearly that we born with the "sense" of what is good and bad. Is like intuition- u feel what's correct and it proves to be true and you can't explain logically why.

  • Another lie of evil- don't use your senses to perceive correct this real world created by God, but instead anulate all his creation.

  • I just watched 6 of these episodes in a row and I feel like I know everything in the universe

  • God, I wanna be a Green brother.

  • What really exists is a headache even for quantum physicists. In one of the interpretations, things do not exist until observed by a mind.

  • I would argue that we never stop sensing ourselves even during sleep.

  • Locke a quantum view of perception

  • This thought may be an exercise in sophistry, as I am writing extemporaneously. So, please be respectful with your replies, as it is very possible that I am wrong. But isn’t it possible, that Locke simply miscategorized his primary and secondary qualities? I can imagine a colorless apple WITH texture. Therefore, isn’t it possible that texture is also a primary quality? Nowadays, we have the technology to determine texture with percision. So hasn’t the technological revolution produced some amount of insight into what should be perceived as a primary quality?


  • "The perceivers themselves don't have any physical form. They're just disembodied minds perceiving things that aren't really there".

    I've been there on a few wild nights in college.

  • If I can't imagine an object with my eyes closed, is it really there? Are my eyes already closed and I'm just imagining the world around me? When people say "imagine an object close your eyes" can they actually experience it, but not like me who can't imagine it at all?

  • philosophy always gives me a fookin headache lmao

  • Um ..

  • For the early Mahayana Buddhist scholars these arguments were mental training exercises . Used to prepare novices for the more advanced studies that they would undertake later on


  • John Locke a smart man but not in this field.

  • If everything around us is how we perceive things, then when we sleep we can't perceive and therefore we cease to exist. This is totally wrong right coz we still exist when we sleep.

  • Beyond awesome. Thank you for this !

  • English Philosopher… Johnlock.

  • Isn't this the same argument for the idea that we live in a simulation?

  • Iam currently taking a minor "philosiphy of social sciences" this makes everything fun. GOD BLESS YOU MANNNNNN

  • Well we know who's side you're on! 8:20 smh

  • I have a theory: if our bodies are just tools for our souls and these tools have so called senses, then our souls might not fully read/understand/sync with these senses which doesn't mean that we cannot trust ourselves but haven't learnt how to recognise the signs.

  • Philosophers presenting Rationalism (Argument) for Empiricism

  • This empiricist version of the cartesian cogito is really interesting.

  • Poor absolutist, things don't have to be all objective or subjective or objective and then subjective they can be both simultaneously, this isn't a problem. The apple has a certain weight, this is objective, it can be reliability measured and proven, the color is subjective because we all perceive colors differently to some degree. It is entirely ok for the apple to be simultaneously objectively a certain weight while being subjectively a certain color. SMH

  • Berkeley’s conclusion is so frustrating, instead of saying there’s a flaw in his thinking he just shoved god into his logic to try and make sense of it.

  • dudes were talking about Musk's Virtual Reality Theory 200 years ago…

  • Alright! freakin' radical, man!

  • When I am hearing about quantum determinancy and observer effects, and the experiments which dont work to prove determinancy, I imagine God already perceived the whole universe for all time, that way they arent wrong and I dont have to think to hard.

  • I'm greek and I have something to tell you
    thank you …..

  • Is there anyway you can teach us math as well ? 🥺

  • Im a skeptical rational empiricist. Covered with a nice saus of misery and truthful loneliness.

  • Why is nobody talking about how perfect that apple is!!

  • Im lost

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