Philosophy of Science
Lecture 1
What is science?
We are going to think about the question whether psychology is a science
Abbreviations
Exploring humans (EH)
Hans Dooremalen (HD)
Program today
1. What is philosophy of science?
2. What is the importance of philosophy of science for you?
3. Epistemology: rationalism vs empiricism
4. Summary and conclusion
5. Preview
What is philosophy of science
= Critical reflection on what science is, does and how it generates knowledge
e.g. why do Stephen Hawking’s claims about black holes fall within the realm of science and Joke
Damman’s claims about white ghosts do not?
What is science:
We use the word ‘science’ often and use it in the right manner
But what are the characteristics of science?
We have an idea of what science is, but no clear answer. i.e. we use the work correctly and
can tell when people do not use it properly, but it is not easy to answer the question what
exactly is science?
What is the importance of philosophy of science for you?
As an academic you should be able to explain why psychology is classified as a science
this requires knowledge: one needs to know different answers that have been given in the history
of thinking about science to ‘what is science’
and skills: to reflect on questions like: ‘is psychology a science?’
and character knowledge and skills built this
By thinking critically about science, and about scientific status of psychology, one can gain insight in
psychology as a science, and thus become better psychologists.
TUI understanding society advancing society
Epistemology
= theory of knowledge
3 questions:
1. What is (certain) knowledge?
2. How can we justify that knowledge?
3. What is the source of knowledge?
, Philosophy of Science
Two views traditionally:
1. Rationalism = real knowledge is derived from the ratio, reason; proper use of out reasoning
capacities (comes from Plato)
2. Empiricism = real knowledge comes from sensory experience (goes back to Aristotle)
Is it possible to have real knowledge?
rationalists and empiricists say so
Scepticism
= “perhaps the conclusion must even be that we do not know anything at all, and never will”
Socrates in the market square asked difficult questions
it is not certain knowledge that keeps the building of science standing, it is faith
Rationalism
General claim: real knowledge stems from our reason (ratio)
Associated claim: there is innate knowledge/inborn nativism
There are things that we can be certain of!
1. Plato
Plato is radical rationalism not the general view of rationalism
To learn is to remember (=anamnèsis)
There is no new knowledge – you do not really learn anything (you already have all
knowledge when born, but you just forgot it)
Why did he claim this? Plato believed in reincarnation
Plato believed that before you were born, you had all real knowledge (and you lost that knowledge
when you were born)
so, no new knowledge, but remembered knowledge
Epistème = knowledge of how the things are
Doxa = opinion about how the things are these can be wrong sceptics belong to this according
to Plato
Plato knowledge = justified & true belief
Heraclites said: if in our world (the world we perceive with our senses) everything changes
constantly, then nothing is panta rhei
And that means we can only acquire doxa (belief), not epistème (which would amount to scepticism)
Plato did not want scepticism
So, he said: if knowledge is not possible about this world, there should be knowledge about another
world (a different world than the world we perceive with our senses) knowledge =/= perception
Ideas/forms exist apart from us in a World of Ideas/World of Forms
The soul is akin to this world
Acquiring knowledge is to remember these Ideas – anamnèsis
illustrated with Allegory of the Cave (prisoners in a cave only perceive shadows, but not the actual
objects)
We cannot gain knowledge about these Forms with our bodily senses, but we can gain knowledge
using our capacity for reasoning rationalism
, Philosophy of Science
Empiricism
General claim: empiricists believe that the source of knowledge is the experience gained through
sensory perception
This is a common-sense view if you want to know how something is, you have to look (or listen)
Associated claim: if all knowledge comes from experience via perception, there is no innate
knowledge
Empiricist =/= empirical
Empirical is the oppositive of purely hypothetical
1. Aristotle
Rejected Plato’s two-worlds theory: there is only one world, and that is the one we can perceive with
our senses
This implies a rejection of innate ideas: man is a tabula rasa (= blank slate)
Peripatetic principle = nothing is in the intellect which was not first in the senses (Aquinas)
Is Aquinas’ interpretation of Aristotle correct?
The key the Aristotle’s epistemology is indeed sensory perception
In that sense we can rightly call Aristotle an empiricist
But he does have some rationalist elements in his ‘empiricist’ epistemology
Aristotle rejects the Ideas World (e.g. Idea Chair)
But he accepts only the existence of concrete, individual things (individual chair)
how then do we arrive at a universal, abstract concept (the concept ‘chair’ that applies to all
individual chairs)?
Induction = empirical procedure by which we move from concrete to universal (epagogè)
= conclusions based on observation of some cases in which A was also B or was followed by B, that A
is always B or is always followed by B
e.g. you perceived a few humans that were mortal, so you can establish that all humans are
mortal
Problem with induction
Are you sure that all humans are mortal?
No: on the basis of observation alone one can not tell that this statement is true, it’s just a
correlation
Yet Aristotle did believe that ‘all humans are mortal’ was necessarily true
Aristotle’s solution
Induction is only a first step
Second step: through our unfailing intellectual capacity of the mind we can understand that
abstractions like ‘all humans are mortal’ are necessary truths
Intuitive induction (= understanding)
But that is a rationalistic element in his epistemology!
Aquinas may have misclassified Aristotle as an empiricist (however he is often seen as empiricist)
Role of Aristotle in the late middle ages
Catholic church had a lot of power in the Middle Ages
Issues relating to knowledge and reality were resolved either by quoting the Bible or by quoting
Aristotle (lived before Christ); two paths to the truth:
1. Revelation
2. To use your good sense
, Philosophy of Science
Aquinas tried to unite Christian teaching with the pagan ideas of Aristotle (‘The Philosopher’)
Example:
Aristotle had a theory about matter and form. Matter (e.g. marble) is potentially something (e.g. a
statue). The shape makes something that actual thing. The statue can break again process of
creation and decay (like what Heraclites said: everything changes constantly)
Aquinas argued that God has put this process of creation and decay in motion (God is the first
cause/unmoved mover)
One could not just simply disagree with Aristotle, for what he has said was the truth that was in the
Bible attacking Aristotle implied attacking the Bible
Aristotle’s view on experiments
Aristotle did no experiments because he thought that they would not teach us anything about the
natural world
Reason: acquiring knowledge about natural world with the method of observation, by manipulating
we make the world go against the natural way of things, so we do not learn anything about the
natural world
Consequence; in the Middle Ages both philosophy and science came to a halt for science to
continue, we needed to reject Aristotle’s view
Lecture 1
What is science?
We are going to think about the question whether psychology is a science
Abbreviations
Exploring humans (EH)
Hans Dooremalen (HD)
Program today
1. What is philosophy of science?
2. What is the importance of philosophy of science for you?
3. Epistemology: rationalism vs empiricism
4. Summary and conclusion
5. Preview
What is philosophy of science
= Critical reflection on what science is, does and how it generates knowledge
e.g. why do Stephen Hawking’s claims about black holes fall within the realm of science and Joke
Damman’s claims about white ghosts do not?
What is science:
We use the word ‘science’ often and use it in the right manner
But what are the characteristics of science?
We have an idea of what science is, but no clear answer. i.e. we use the work correctly and
can tell when people do not use it properly, but it is not easy to answer the question what
exactly is science?
What is the importance of philosophy of science for you?
As an academic you should be able to explain why psychology is classified as a science
this requires knowledge: one needs to know different answers that have been given in the history
of thinking about science to ‘what is science’
and skills: to reflect on questions like: ‘is psychology a science?’
and character knowledge and skills built this
By thinking critically about science, and about scientific status of psychology, one can gain insight in
psychology as a science, and thus become better psychologists.
TUI understanding society advancing society
Epistemology
= theory of knowledge
3 questions:
1. What is (certain) knowledge?
2. How can we justify that knowledge?
3. What is the source of knowledge?
, Philosophy of Science
Two views traditionally:
1. Rationalism = real knowledge is derived from the ratio, reason; proper use of out reasoning
capacities (comes from Plato)
2. Empiricism = real knowledge comes from sensory experience (goes back to Aristotle)
Is it possible to have real knowledge?
rationalists and empiricists say so
Scepticism
= “perhaps the conclusion must even be that we do not know anything at all, and never will”
Socrates in the market square asked difficult questions
it is not certain knowledge that keeps the building of science standing, it is faith
Rationalism
General claim: real knowledge stems from our reason (ratio)
Associated claim: there is innate knowledge/inborn nativism
There are things that we can be certain of!
1. Plato
Plato is radical rationalism not the general view of rationalism
To learn is to remember (=anamnèsis)
There is no new knowledge – you do not really learn anything (you already have all
knowledge when born, but you just forgot it)
Why did he claim this? Plato believed in reincarnation
Plato believed that before you were born, you had all real knowledge (and you lost that knowledge
when you were born)
so, no new knowledge, but remembered knowledge
Epistème = knowledge of how the things are
Doxa = opinion about how the things are these can be wrong sceptics belong to this according
to Plato
Plato knowledge = justified & true belief
Heraclites said: if in our world (the world we perceive with our senses) everything changes
constantly, then nothing is panta rhei
And that means we can only acquire doxa (belief), not epistème (which would amount to scepticism)
Plato did not want scepticism
So, he said: if knowledge is not possible about this world, there should be knowledge about another
world (a different world than the world we perceive with our senses) knowledge =/= perception
Ideas/forms exist apart from us in a World of Ideas/World of Forms
The soul is akin to this world
Acquiring knowledge is to remember these Ideas – anamnèsis
illustrated with Allegory of the Cave (prisoners in a cave only perceive shadows, but not the actual
objects)
We cannot gain knowledge about these Forms with our bodily senses, but we can gain knowledge
using our capacity for reasoning rationalism
, Philosophy of Science
Empiricism
General claim: empiricists believe that the source of knowledge is the experience gained through
sensory perception
This is a common-sense view if you want to know how something is, you have to look (or listen)
Associated claim: if all knowledge comes from experience via perception, there is no innate
knowledge
Empiricist =/= empirical
Empirical is the oppositive of purely hypothetical
1. Aristotle
Rejected Plato’s two-worlds theory: there is only one world, and that is the one we can perceive with
our senses
This implies a rejection of innate ideas: man is a tabula rasa (= blank slate)
Peripatetic principle = nothing is in the intellect which was not first in the senses (Aquinas)
Is Aquinas’ interpretation of Aristotle correct?
The key the Aristotle’s epistemology is indeed sensory perception
In that sense we can rightly call Aristotle an empiricist
But he does have some rationalist elements in his ‘empiricist’ epistemology
Aristotle rejects the Ideas World (e.g. Idea Chair)
But he accepts only the existence of concrete, individual things (individual chair)
how then do we arrive at a universal, abstract concept (the concept ‘chair’ that applies to all
individual chairs)?
Induction = empirical procedure by which we move from concrete to universal (epagogè)
= conclusions based on observation of some cases in which A was also B or was followed by B, that A
is always B or is always followed by B
e.g. you perceived a few humans that were mortal, so you can establish that all humans are
mortal
Problem with induction
Are you sure that all humans are mortal?
No: on the basis of observation alone one can not tell that this statement is true, it’s just a
correlation
Yet Aristotle did believe that ‘all humans are mortal’ was necessarily true
Aristotle’s solution
Induction is only a first step
Second step: through our unfailing intellectual capacity of the mind we can understand that
abstractions like ‘all humans are mortal’ are necessary truths
Intuitive induction (= understanding)
But that is a rationalistic element in his epistemology!
Aquinas may have misclassified Aristotle as an empiricist (however he is often seen as empiricist)
Role of Aristotle in the late middle ages
Catholic church had a lot of power in the Middle Ages
Issues relating to knowledge and reality were resolved either by quoting the Bible or by quoting
Aristotle (lived before Christ); two paths to the truth:
1. Revelation
2. To use your good sense
, Philosophy of Science
Aquinas tried to unite Christian teaching with the pagan ideas of Aristotle (‘The Philosopher’)
Example:
Aristotle had a theory about matter and form. Matter (e.g. marble) is potentially something (e.g. a
statue). The shape makes something that actual thing. The statue can break again process of
creation and decay (like what Heraclites said: everything changes constantly)
Aquinas argued that God has put this process of creation and decay in motion (God is the first
cause/unmoved mover)
One could not just simply disagree with Aristotle, for what he has said was the truth that was in the
Bible attacking Aristotle implied attacking the Bible
Aristotle’s view on experiments
Aristotle did no experiments because he thought that they would not teach us anything about the
natural world
Reason: acquiring knowledge about natural world with the method of observation, by manipulating
we make the world go against the natural way of things, so we do not learn anything about the
natural world
Consequence; in the Middle Ages both philosophy and science came to a halt for science to
continue, we needed to reject Aristotle’s view
