六天重建世界

《Meditations on First Philosophy》（1641）

Descartes最重要philosophical work

六个"meditations"（沉思）——

每个=一天的philosophical journey

从complete doubt——

到certainty about:

  • Self（我）
  • God（上帝）
  • External world（外部世界）
  • Mind-body distinction（心身分别）

Like spiritual exercises——

Reader invited同行此journey

不只是read——

而是meditate with Descartes

重新经历doubt和discovery

写作背景

为什么拉丁语？

不像《方法论》（法语）——

《沉思录》用拉丁语written

For learned audience：

Philosophers、theologians

尤其：

希望获得Church approval

Objections and Replies

Descartes sends manuscript to scholars——

收集objections

然后publish《沉思录》with：

  • Original text
  • Six sets of objections（from various philosophers、theologians）
  • Descartes’s replies

包括objections from：

Hobbes、Gassendi、Arnauld

这format=valuable：

See challenges、Descartes defend

Dialectical

First Meditation：怀疑的深渊

“What can be called into doubt”

Project

Demolish all former opinions——

Start fresh

不是examine每个belief individually——

而是attack foundations

If foundations crumble——

Everything built on them falls

三层怀疑

1. Sensory deception

Senses sometimes deceive：

Tower远看圆，近看方

Stick在水中显得弯

“Whatever has once deceived me——

I never trust again”

所以：

Can’t trust senses about anything

但objection：

Certain things seem undeniable：

我坐在火炉旁——

穿着dressing gown——

This paper在hand

How could这些be false？

2. Dream argument

Descartes’s response：

Madmen think类似things（when actually not true）

但"I’m not mad"

However：

Dreams！

在dreams中——

I’ve thought我坐在火炉旁——

When actually在bed asleep

“How often夜晚persuade me——

Familiar things（sitting、wearing clothes）——

When实际naked in bed！”

No certain signs区分waking和dreaming

所以：

Maybe this moment=dream

Everything I perceive=illusion

3. Evil demon（恶魔假设）

但即使dreaming——

Certain truths seem remain：

Mathematics：

2+3=5

Square有四边

这些true——

Whether awake或dreaming

Descartes pushes further：

Suppose不是benevolent上帝创造我——

而是evil demon——

Supremely powerful、cunning

Devoted to deceiving me

This demon make me think：

2+3=5（when actually不是）

我有body（when I don’t）

External world exists（when doesn’t）

如果这样的demon——

Then nothing certain

连mathematics都可疑

Meditation结束

Descartes end First Meditation in despair：

一切可疑

没有firm ground

Trapped in doubt

但他说：

必须resist old beliefs——

保持这doubt——

Deliberately——

Like prisoner who enjoy imaginary freedom in dreams——

怕醒来回到painful waking

这是为什么assume evil demon：

Help maintain skepticism

Until find certainty

Second Meditation：我思故我在

“The nature of the human mind”

Cogito的Discovery

昨天：complete doubt

今天：seek certainty

Descartes realize：

即使evil demon deceive me about everything——

有一件事certain：

我exist

Why？

To be deceived，我必须exist

Demon can make me think错things——

但can’t make non-existent thing think

所以：

“I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.”

这是famous cogito——

虽然exact phrase"cogito ergo sum"不在《沉思录》——

（在《方法论》和其他works）

但idea same

我是什么？

Now know我exist——

但what am I？

Previously thought我=：

  • Body with face、hands
  • Nourished by food
  • Walk、sense
  • Think

但body可疑（demon可能deceive）

所以can’t be certain我=body

但thought？

这不可疑！

即使all thoughts=false——

Thinking itself=certain

结论：

我=thinking thing（res cogitans）

“What am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, wills, refuses, and also imagines and senses.”

All these=modes of thinking

这是我的essence

Wax argument

Famous example clarify mind>body knowledge：

Take piece of wax——

Fresh from honeycomb：

  • Sweet taste（honey）
  • Floral scent
  • Particular color、shape
  • Hard、cold
  • Makes sound when struck

Now bring near fire：

  • Taste去
  • Scent evaporates
  • Color changes
  • Shape变
  • Becomes liquid、hot
  • No sound when struck

所有sensory properties changed——

但仍same wax

What remains？

Not sensory qualities——

而是：

Extended、flexible、changeable thing

这是通过intellect grasp——

不是senses

Conclusion：

物质本质=通过mind知道——

不是senses

And：

Mind itself更easily known than body！

因为every time我perceive anything——

I’m aware of my thinking

Third Meditation：上帝的证明

“The existence of God”

Inventory of ideas

Now certain我exist as thinking thing——

但external world？

First：examine我的ideas

Three types：

1. Innate（天赋）：

Born with me

Example：idea of thought、existence

2. Adventitious（外来）：

From outside

Example：heat（feels like from fire）

3. Invented（虚构）：

Created by me

Example：mermaids、unicorns

Idea of God

我有idea of：

Infinite、perfect being（上帝）

Question：

Where这idea come from？

Can’t be invented——

因为我=finite、imperfect

How could finite create idea of infinite？

Effect不能greater than cause

Can’t be from external things——

They’re finite too

所以：

Must be innate——

Placed in me by上帝

Like craftsman’s mark on work

结论：

上帝must exist——

To put this idea in me

Causal argument

More formally：

Idea of perfection requires cause——

至少as perfect as content of idea

我=imperfect（我doubt、lack things）

所以我can’t be cause

只有actually perfect being——

Can cause this idea

Therefore上帝exists

上帝不欺骗

Important conclusion：

上帝=perfect

Deception=imperfection（依赖cunning，indicates weakness）

所以上帝不deceive

This will be crucial later——

For trusting clear and distinct perceptions

Fourth Meditation：错误的来源

“Truth and falsity”

Problem

如果上帝perfect、不deceive——

Why do I make errors？

Isn’t error=kind of deception？

Descartes’s solution

上帝给我两faculties：

1. Intellect（理智）：

Perceives ideas

Itself不err——

只是represents

2. Will（意志）：

Judges、affirms、denies

Infinite scope——

Can affirm anything

错误来自：

Will exceeding intellect

我judge关于things——

我don’t clearly perceive

这是my fault，不是上帝’s

上帝给我freedom——

我misuse it

Remedy

只assent to clear and distinct perceptions

Withhold judgment when unclear

这way avoid error

Fifth Meditation：物质本质与上帝

“The essence of material things”

物质的essence

我can clearly and distinctly perceive：

物质=extended substance

Extension=essence of body/matter

这include：

  • Size
  • Shape
  • Position
  • Motion

Mathematical properties

Ontological argument

Second proof of上帝：

Consider idea of most perfect being

Existence=perfection

（如same way triangle必有three angles）

所以：

上帝必exist

不能conceive perfect being without existence——

Like不能conceive triangle without three angles

This is Anselm’s argument（version）

Controversial！

Later Kant demolish（他说）

Sixth Meditation：物质事物的存在

“The existence of material things”

Mind-body distinction

我clearly perceive：

Mind=thinking、unextended

Body=extended、non-thinking

Clear and distinct=real distinction

所以：

Mind和body=two distinct substances

我can exist without body

（Though currently united）

External world的proof

我有sensory ideas（colors、sounds、etc.）

这些come to me involuntarily

Not from my will

所以must have external cause

Options：

1. 上帝directly cause them

2. Some other substance

3. Material things themselves

如果(1)或(2)——

And no material things——

Then上帝deceive me

（Because strong inclination believe in material world）

但上帝不deceive

所以：

Material things exist！

Mind-body union

但mind和body不只是distinct——

Also intimately united：

我不只是in body——

Like pilot in ship

Rather：

Intermingled with it

Evidence：

Pain——

不只是intellectual awareness of damage——

而是felt directly

Hunger、thirst——

Confused sensations——

Result of union

Errors of senses

Senses sometimes err——

Example：

Dropsy patient feel thirst——

但drinking=harmful

Nature（mind-body composite）mislead

但这不=上帝欺骗

因为：

Senses designed for usual cases——

Not sickness

Body=machine——

Sometimes malfunction

We should use reason correct sensory errors

核心困难

Cartesian circle

Biggest criticism：

Descartes need上帝——

To guarantee clear and distinct perceptions true

但he used clear and distinct perceptions——

To prove上帝！

Circular？

Descartes’s defense unclear

Maybe：

Cogito和上帝proofs=self-evident when attending——

不需要上帝guarantee

上帝只guarantee memory of past clear perceptions？

Scholars debate

Mind-body interaction

如果mind=unextended——

Body=extended

Completely different substances——

How interact？

Descartes说：through pineal gland

但HOW？

Mechanism unexplained

This problem plague后来

Solutions tried：

  • Occasionalism（Malebranche）：上帝coordinate
  • Pre-established harmony（Leibniz）：pre-programmed
  • Materialism：no separate mind
  • Idealism：no separate matter

Descartes start debate——

Still not fully resolved

遗产

Method

Systematic doubt

Build from certain foundations

这成为philosophical ideal（for some）

Rationalism

Knowledge through reason

Innate ideas

Mathematics as model

Inspire Spinoza、Leibniz

Subjectivity

“I think”=starting point

Epistemology=primary

This shape modern philosophy

Mind-body problem

Dualism=influential but problematic

Generate centuries of debate

现代读者的体验

诚邀亲历

《沉思录》designed for reader meditate along

不只是read arguments

Try doubt yourself——

See if你can resist

Experience cogito的force

Contemplate上帝

这是experiential、not just logical

某些arguments unconvincing

Especially上帝proofs——

Modern readers often skeptical

但cogito仍powerful

Mind-body distinction=intuitive for many

（Though也many materialists now）

Historical importance>truth？

Maybe Descartes’s arguments不都succeed——

但undeniably shape后来thought

Must understand Descartes——

To understand modern philosophy

实践沉思

Day 1：Doubt

Try怀疑：

What can you really be certain of？

Senses？Dreams？

Scary but clarifying

Day 2：Self

What survives doubt？

Awareness itself？

“I think”=undeniable

Day 3-4：Foundations

What grounds知识？

For Descartes=上帝

For you=？

Reason？Experience？

Day 5-6：World

How know external world real？

Descartes’s proof unconvincing to many

但problem=real

How bridge gap between mind和world？

六日旅程——

From complete doubt——

Through"我思"——

到上帝——

到world

Descartes rebuild——

From cogito

一切

Ambitious！

Succeed？

Parts yes——

Parts questionable

但attempt=magnificent

Invite us——

Think for ourselves——

Doubt、question、seek certainty

这spirit——

更important than

Specific conclusions

每个人——

Can take——

Own six days

Own meditations

Own journey——

From doubt——

To truth

Descartes show——

It’s possible

“我思，故我在”

Start here

See where——

You end up