Lecture 05 - Descartes! + Locke & Leibniz

What were the times like when Descartes was alive? How were science and religion operating?

he lived in a world where it was still risky to challenge religious doctrine and authority

he was a devout Catholic himself

he pressed Aristotelian naturalism and the idea that the human body is a non-metaphysical, mechanical thing operated by an immortal soul

impressed by the development of mechanical statues and robots

How did Descartes explain human motion in a mechanical way?

studied bodies and saw lots of nerves and organs that held fluids

proposed that animal spirits flowed through the nerves and pushed and pulled the body in different ways

• classic depiction of a reflex

Where did Descartes focus on in the body?

pineal gland

• he identified the importance of the brain in thought and emotion more so than the heart

How did Descartes describe pain in the body? use foot in fire example

1. foot in fire

2. triggers sensation mediated by animal spirits

3. response goes to brain to say ouch

4. remove foot from fire

How did Descartes describe the soul?

he replaced Aristotle’s vegetative and sensitive soils with a physical substance

• physiological responses and actions happen mechanically

• believed humans were like clocks in the mechanical way

  • extreme take compared to what others were saying

• “the soul of beasts is nothing but their blood”

What was Descartes first rule? How is it related to the Greeks?

“never to accept anything as true unless . . . it presented itself so clearly and distinctly in my mind that there was no reason or occasion to doubt”

• more Platonic than Aristotelian since it has to be convincing in his mind not through observation

In sum, what was Descartes’ philosophy? What was his famous phrase?

soft mind-body dualism (compared to Plato)

emphasized the differences between the world as you perceive it and reality

• imperfect perception

emphasized the distinct individual “soul”/identity associated with rationality: I think therefore I am

a strongly naturalistic perspective but also a strong metaphysical aspect

• part of you may be travelling as a robot, part of you in divine and metaphysical

• mostly ok with the church

Where did Descartes suggest that the body and mind interact?

pineal gland

• compartmentalized all of the processes into this area

• one of the first to believe the soul and brain were related

sensations direct there and non-reflexive actions could spring from there

What is the pineal gland actually responsible for?

release of melatonin and related to sleep

• it is sensitive to light but not in the way Descartes thought

What was Descartes’ legacy?

he located the mind/soul in the brain, not the heart

believe many basic functions of the body are mechanical

animals viewed as machines

correctly saw brain → nerves → motor control BUT got mechanisms wrong

recognized awareness of subtle bodily sensations

Who were Locke and Leibniz?

influential philosophers in the 1600s

revived head-to-head Aristotle vs. Plato conflict

Aristotle and Locke = empiricism

Plato and Leibniz = rationalism

Who was John Locke?

1632-1704

a man of all seasons - philosopher, scientist, physician

established the Royal Society of London as a place for scientific discussion

development of serious empiricism

• “with so many smart people around, how can you decide who is right”

• Descartes’ first rule is not good enough

Why was Locke an empiricist? What was his religious basis for empiricism?

Locke was one of the first scientists that wasn’t Catholic (he was Protestant)

religious basis for empiricism: God gave us senses and it would be an affront not to use them

What did Locke believe about using our senses?

using the sense not just for our convenience but its important for resisting temptation

• to protect ourselves from delusion we have to pay attention to our senses

What did Locke say about tabula rasa? What were the two kinds of experiences?

the mind is a blank slate (tabula rasa) at birth and we gain knowledge through experience

compared the mind to a camera obscura

1. sensations of objects in the external world

2. reflections of the mind’s operations leading to ideas

What was Locke’s beliefs about simple ideas and complex ideas? What are simple and complex ideas?

we develop complex ideas from simple ones and simple ones from reflections on sensations

1. simple - ideas based on the earliest sensations and reflections occurring in infants

2. complex - Ideas produced when simple ideas are consciously combined by the mind

focused on thought experiments

What is the Locke and Molyneux problem?

could a newly sighted blind person visually distinguish a cube vs. a sphere if they could distinguish them by touch before?

• Locke believed you build associations overtime but no innate ideas > build associations through sensations → then they gain sight → no because visual knowledge requires new learned associations

• “the person had never experienced these shapes through vision, their mind could not yet connect visual cues to past touch

new evidence doesn’t fully support this

What was Thomas Hobbes’ view of humanity and how did Locke change it or challenge it?

Hobbes: since people are innately self-centered and aggressive, people have to “contract”/band together for mutual protection

• we need to develop a social contract, to protect yourself you need to band with others

Locke: more optimistic perspective

• everyone entered into a voluntary social contract that allows all perspectives to be respected and considered on their merits

  • the start of democracy?

Who was Gottfried Wilhelm Leibniz? What did he develop/interested in?

1645-1716

German philosopher

very thinking to Locke

admiration of Descartes about mechanical things

designed windmills and earliest calculators

• “let us calculate”

interest in internal sensations

What did Leibniz say about the monad theory?

monad theory suggested that the world is made up of fundamental units that are all alive and aware

What did Leibniz believe?

Favoured a cosmic view of interconnected, unseen forces

• met van Leeuwenhoek (inventor of microscopes) and believed monads came from this

Associated with continental nativism

Locke vs. Leibniz ideas? Which side did the world end up taking?

revived the Socrates/Plato vs. Aristotle debate

Leibniz = importance of innate, unseen things, e.g. monads

everything moved towards empiricism

For Leibniz, what are rational monads and apperception?

Leibniz used his own terms:

rational monads: units corresponding to the conscious souls or minds of humans and capable of apperception

apperception: process that occurs when ideas are registered in consciousness, accompanied by self-awareness and become a subject to focus attention to

To who was the rational mind in control?

Descartes and Locke

Leibniz thought that minute perceptions and minor apperceptions were more common and important than appreciated

• We are experiencing all kinds of sensations all the time/bombarded with minute perceptions all the time

• he provided a basis for unconscious psychological processes

What was Leibniz’s Roar of the Sea?

Day-to-day conscious perception is a lot like watching the waves, it is an impressive experience and causes you to focus on it

• There are also a lot of smaller details and aspects to the overall sensory experience of the waves

Our conscious perception is like watching waves -> actually comprised of many smaller perceptions, some of which may be more important than others

• You are picking and choosing what you are experiencing

wave e.g.

1. When you stand on the beach, you hear a single, loud roaring sound from the crashing waves

2. That loud noise is actually made up of millions of tiny, individual sounds from every single drop of water hitting the shore

3. You cannot hear the sound of one single drop of water by itself. However, you must still perceive each tiny sound faintly, or you could not hear the loud roar of the whole ocean combined