Plato and the Forms

• According to Plato, common sense is wrong. We do not sense the world as it really is.• The senses present the world in a confused way.•The mind ‘sees deeper’. It sees the true natures of things.•Plato explained this with the Allegory of the Cave

The analogy of the cave:

ordinary mortals see only the shadows of

reality.

The real things – forms – exist

outside.

The forms project their

shadows onto the cave wall…

…just as the forms are somehow

dimly projected into

real things.

The Forms

• Reality contains forms. They are the timeless and changeless natures of things.

• They contrast with particular things in the ordinary world (of appearances) which are constantly changing.

• But why believe this story? How do acquire knowledge?

So, beauty can’t belong to the

world open to the senses.

Plato, Change and Sameness

But there is nevertheless

something stable here: beauty itself. These beautiful things

must ‘share’ it to be all called beautiful.

Beauty itself cannot change or be

destroyed: we could still talk and think

about it in the absence of beautiful things.

Beauty belongs in a

different realm to the realm of appearances

and it is reason that

gives us access to it.

The world shows signs of both stability and change,

difference and plurality.

A beautiful painting must be created, may be adjusted and may be destroyed: all

examples of change.

Two beautiful pictures may look very different

yet both be beautiful.

There can be many beautiful things.

The senses only reveal a world of

change.

The Imperfection Argument

We know many truths about

circles

Area = πr2

360o in a circle.

But no circles we see or draw

are perfect.

So, our knowledge must

be of some perfect circle - the Form of the circle.

CircleMagnified section of

circumference

Ideal geometrical circles have unjagged circumferences with no width and are infinitely thin.

And since it can’t be sensed, it must

be grasped by reason.

The Knowledge Argument

Knowledge is of truths - if you know something, it can’t

be false.

In the world of appearances, everything is

changing.

It is sunny now but it might not be later.

I cannot therefore know it is sunny.

I can merely have the opinion or believe that it

is.

Knowledge must be of changeless things…

…the forms…

…which cannot exist in the world of

appearances accessible to my senses …

…and so exist in a separate realm

accessible to reason.

The “One Over Many” Argument

The “one over many” argument: if x and y are badgers, there must be something – the

Form of the badger – that they have in common. They both “participate in” the Form of

the badger.

What makes something the kind of thing it is?

What makes a badger a badger?

What makes two things members of the same kind?

What makes these two things badgers?

Participation

World of appearances World of forms

Form (archetype) of the badger

There must be some explanation for why things belong in kinds.

These days, philosophers talk of universals instead of forms.

The Form of a badger is not present where the badgers are but exists in a different realm.

The universal badger exists in each and every badger. It is quite unlike an ordinary object, as an object can be only in one place at any one time. Objects are a type of particular. But the universal

exists in many places at once – it is repeated throughout its instantiations – and hence is called a

universal.

Fundamentally, however, we’re talking about the same thing – an entity that makes a particular belong to a

kind or makes it the kind of thing it is.

Aristotle thought forms were immanent – located in the physical realm where their instantiations are (he would have understood them as universals) whereas Plato

thought they were transcendental – located in another realm altogether.

Why study the forms?

This is useful: we like beautiful things and we want to praise acts of

goodness and punish badness.

He was searching for the nature or essence or, to use Plato’s word, the form of beauty.

But we also want to go deeper and ask what it is that we recognise.

We recognise examples of beauty and goodness.

Socrates would ask, “What is beauty? Truth? Justice?”

There is obviously a practical angle. People differ over what they think is right.

People are sometimes uncertain. We need to remedy this.

But there is also a purely philosophical angle: simply finding out the nature of the

reality we inhabit.

The Context Argument (*)

Something F in one context may

not be F in another.

Picture A may be beautiful in relation

to picture B...

Context 1 Context 2

...but not in relation to picture C.

Since the painting can be beautiful and not

beautiful, it can't provide us with a definition of

what is beautiful.

Whatever beauty is, it can't fail to be beautiful. Since any thing that we find beautiful could fail to be beautiful in another context, we

can't simply collect beautiful things together and hope that they will share some simple

sensory property that we can identify as the property of being

beautiful.

We have to look for the Form of the beautiful or beauty: the thing

that makes beautiful things beautiful. It is the essence of

beauty. But it cannot be detected by the senses, only reason. Why? Take a beautiful painting. In one context beautiful, in another not.

But nothing about how the painting appears changes. So,

we're looking in the wrong place if we look for beauty amongst

perceptible properties.

Plato and the Forms: Summary

Reason gives us knowledge of the Forms (universals)–

the essences of things.

The Imperfection Argument: No perfect circle can exist in the sensible world, only

approximations. No actual circle can be infinitely thin and perfectly curved.

The Knowledge/Change Argument:

the Forms are unchanging. Sensory experience reveals a

changing world. So, the Forms are non-sensible.

The Context Argument:

whether a painting is beautiful or not varies with the context but its sensible features do not. So, the Forms can’t be sensible.

Before we were born, our souls

lived in the world of Forms.

In this embodied life, our knowledge of the forms is buried

and must be unearthed by exercising reason – doing

philosophy.

The Forms cannot be detected with the senses

but only with reason.

One Over Many:If x and y are both F, then there must be something, F, that

they have in common.

Knowledge of the forms: Meno and the Slave-boy

How do we know about the form? Because we have

innate ideas, gained from when our souls existed in

the world of forms.

If ABCD is a square and AD is 2 feet, then the area

is……4 ft2

So, if AD = DL, then AL= ?…4ft.

And so the area of ALKJ is…?…8 ft2

This shows that the boy knew all

along the relevant principles of

geometry.

Plato demonstrates this by getting Meno’s slave

boy to prove a mathematical theorem.

No – for ABCD is 4ft2 and there are how

many such squares in ALKJ?Four.

So the area is…?16ft2

Now, BDNM is composed of four parts each of which has what area? 2ft2

So, the area of BDNM is..? 8ft2

By asking a series of questions, Socrates gets the slave boy to work out the area of two squares

When we are born, our soul ‘forgets’ the ideas and they need to be recollected.

Problem: Learning or recollecting?

Was Socrates asking fair questions?

Or was he giving the boy the right answers disguised as questions?

We might defend Plato thus.

Sometimes, all a teacher can do is get you to work

through examples until you ‘get it’ with a flash of understanding.

For example, it might be that you suddenly see how

to calculate a percentage…

…or understand an argument,

such as the ones we’ve looked at

here.

Problem: Forms can’t be sensed.

Common sense tells us that we should believe

our eyes.

But we can’t sense the forms.

We can’t sense God or numbers or

atoms either.

We believe in them as they provide the best

explanation of the world we can sense.

So that is how we should judge whether to

believe in forms or not.

…We must ask whether there’s a

better explanation.

Problem: Will appearance do?

Socrates tells us there is a form of beauty but not of

hair.

There’s no such thing as perfect

hair!

But then how do we identify

hair?

Examples of hair are just like examples of beautiful

things: they differ from one another, change and can

be destroyed

Socrates tells us that appearances

will do.

So, we identify hair on the basis of

(perhaps) what it is made out of, what it looks like, where

it is found.

But why not say the same about beautiful

things?

If we could, we wouldn’t need to say that there is beauty

itself as a strange thing in a realm of forms.

Question: Will ideas do?

Why don’t we say that there isn’t really a perfect

circle ‘out there’…

…it’s just an idea in my mind.

But what about when you think of

it?

It is an idea in

your mind as well.

But what guarantees we have the same

idea?

Perhaps nothing! Just as people have different ideas

about what is right and wrong, why not about maths

and geometry?

Question: Will ideas do?

This won’t work.

…Every people that have ever thought about maths have arrived at the same ideas about numbers and

shapes. Surely this shows there’s just one

true set of ideas.

It is inconceivable

that 2+2=5. Try making it work!

If 2+2=5, then 2=3? And 0=1???

Even babies have some

innate mathematical

skills!

If by putting 2 by 2 I get 5, I could fill the

universe!

And I could change the past by simply thinking about two people I met

yesterday alongside two other people I met yesterday – I could now make a

fifth person appear then!