Thinking about Science
Introduction
3 main branches in philosophy:
1. Ethics/political philosophy
a. What is good/bad?
b. How should I behave?
c. How could I live a fulfilling life?
d. What is a good society?
2. Metaphysics/ontology
a. What exists?
b. Why does something exist rather than nothing?
3. Epistemology (focus on this branch)
a. What is knowledge?
b. When is it justified to believe something is the case?
Knowledge science = branch within epistemology
What is science/scientific knowledge? When do we call a belief, a method, a practice scientific?
Why and how does science generate reliable knowledge?
What distinguishes science from non-science and pseudoscience?
Does science actually tell us something about the world? How do we know?
Difference mental map and real world
Lecture 1: Rationalism and empiricism in ancient Greece
Rationalism = the view that knowledge results from the proper use of human reasoning abilities.
Empiricism = the view that knowledge is generated by our sensory capacities.
1.1 INTRODUCTION
Socrates (470 – 399 B.C.):
What is knowledge?
o Kick-off for the philosophy of knowledge = epistemology
Today: how can we justify knowledge?
2 rival approaches: rationalism vs. empiricism
This debate overlooks communication between people
Rationalism
Maintains that true knowledge about reality derives from the proper use of our reasoning capacities
(intellect, reason or ratio)
Our capacity to think generates ideas and concepts which we cannot arrive at by using our sensory
capacities
Based on the work of Plato
Vs.
Empiricism
Sense experience is the ultimate source of knowledge
The senses are reliable indicators of what reality is like
Based on the work of Aristotle (Plato’s pupil)
,1.2 PLATO’S RATIONALISM
Plato (427 – 347 B.C.):
Famous pupil of Socrates (method of dialectic/cross-examination)
Socrates:
Method of Q&A (intellectual midwifery): assisting others in their philosophizing by asking questions in order
to give birth to new ideas goal: essence of concepts
Not knowing is my only certainty examined concepts to determine their essences (ex. beauty or justice)
Sentenced to death for introducing other new divinities
Plato:
Ontology = the study of being in general ‘why is there something rather than nothing?’
Central issue ancient Greece: what exists and what does not? difference between being and becoming
Parmenides of Elea (510 – 440 B.C.)
Heraclites of Ephese (600 – 540 B.C.)
Both associated with 2 opposing views that set the stage for later developments in antiquity and beyond
Heraclites:
Change (‘flux’ in his words) is the heart of existence
Nothing is, everything becomes view captured in the form of the aphorism ‘panta rei’ ‘everything flows’
methaphor: you cannot step twice in the same river
Nothing is, everything changes
Most people are not able to attain knowledge. Only those few people who are capable of grasping the
hidden and fundamental law (Logos), behind appearances can be said to arrive at knowledge
Parmenides:
Change is the essence of reality people’s senses mislead human beings into thinking that things are
changing all the time
Under all the movement we pick up with our senses, there is a permanent and unchanging reality (the wall is
still the wall, even if the color is changed because of the sun going under)
Everything is, nothing becomes real existence means to be without change
We must rely on reason to discover the unchanging truths about eternal reality
Short:
Parmenides: being is real, change is not rationalist
Heraclites: change is real, being is not empiricist
Empiricists: knowledge is perception
Plato: with the perceived world in constant flux, perceptions and hence knowledge, will vary from moment
to moment, from person to person knowledge ≠ perception
Protagoras (490 – 420 B.C.):
Homo mensura: ‘man is the measure for all things’
Opinion is true to each person which he acquires through sensation no one can ever be wrong about
anything (= empiricist)
Plato: truth and knowledge are about how things really are, not about how they are for me or you.
Therefore, knowledge is not perception.
Plato: the real world cannot be the ever-changing world of appearances, but a supernatural realm which contains
the eternal and perfect Forms (or Ideas) of almost everything influence of geometry (certain knowledge about
ideal figures, not particular instances)
Allegory of human existence allegory of the cave
2
, Allegory of the cave
Prisoners in a cave are chained with their hands and necks so
that their gaze is fixed on a wall. Behind the prisoners is a fire.
Between the prisoners and the fire there is a walkway where
people holding up statues and figures of animals are passing by
(comparison to puppet show). The prisoners have never been
out of the cave and have therefore never seen anything but
these projections on the wall. The prisoners will then mistake
the shadows passing before their eyes for real objects. When a
prisoner is released from his chains, he will first be dazzled by
the fire. It will take some time to convince him that the figures
he sees are more real than the shadows. Once out of the cave,
he is blinded by the sunlight. After a while, he will be able to see the real objects of which the statues and figures,
were copies. He will realize reality once the light of the sun reveals all objects.
Conclusion: human beings mistake appearance for reality.
Plato: the universal Forms are the ultimate realities that ground true knowledge.
Empirical investigation is inadequate for knowledge as it only brings us into contact with a reality that is in constant
Hereclitean flux. Hence, the operation of the senses results in mere belief (doxa), not knowledge (episteme).
Because the Forms belong to a supernatural world we cannot perceive them by using our bodily senses. According to
Plato, we can gain knowledge about this transcendental reality through our capacity for reasoning Plato is a
rationalist.
Nativism = the doctrine that human beings possess innate (inborn) ideas
Closely associated with rationalism
Plato: we are all born possessing all knowledge, the knowledge was lost at birth but if we use our reason
correctly, we are able to remember it all.
o That means there is no new knowledge Plato’s theory about reincarnation
Plato’s theory about reincarnation
The immortal soul belongs to the World of Forms, where it has seen them all, but we forgot about them when our
souls were born into our bodies. Fortunately, the Forms are still accessible through our reason. If we reason well,
we can remember the Forms we saw before birth and thereby come to know the real world.
Dialogue Meno
Explains how knowledge is possessed in the soul’s previous existence in the World of Forms can be recollected.
Dialogue with 3 people: Socrates (the character) defending Plato’s theory, Meno and Meno’s slave. The slave is
poorly educated and knows little about geometry. Socrates intends to show
Meno that the slave could remember mathematical knowledge if he would
reason properly (learning-by-recollection).
[Image shows the square used by Socrates to help the slave reason]
According to Socrates, the slave has figured it out. However, Socrates is leading the slave as he elicits assent to the
geometrical truth. Therefore, the slave does not figure things out himself. Meno, however, is convinced that the
slave remembered all this just by using his intellect.
1.3 ARISTOTLE’S EMPIRICISM
Empiricists argue that the source of knowledge is not reason but sensory experience. Our senses bring us into
immediate contact with the world. The experiences we have when we explore the world must therefore constitute
the foundation of knowledge.
Artistotle addressed subjects such as physics, biology and politics. For scientific progress to be made possible, we
must leave abstract theorizing and turn to the empirical facts of nature.
Aristotle:
3
Introduction
3 main branches in philosophy:
1. Ethics/political philosophy
a. What is good/bad?
b. How should I behave?
c. How could I live a fulfilling life?
d. What is a good society?
2. Metaphysics/ontology
a. What exists?
b. Why does something exist rather than nothing?
3. Epistemology (focus on this branch)
a. What is knowledge?
b. When is it justified to believe something is the case?
Knowledge science = branch within epistemology
What is science/scientific knowledge? When do we call a belief, a method, a practice scientific?
Why and how does science generate reliable knowledge?
What distinguishes science from non-science and pseudoscience?
Does science actually tell us something about the world? How do we know?
Difference mental map and real world
Lecture 1: Rationalism and empiricism in ancient Greece
Rationalism = the view that knowledge results from the proper use of human reasoning abilities.
Empiricism = the view that knowledge is generated by our sensory capacities.
1.1 INTRODUCTION
Socrates (470 – 399 B.C.):
What is knowledge?
o Kick-off for the philosophy of knowledge = epistemology
Today: how can we justify knowledge?
2 rival approaches: rationalism vs. empiricism
This debate overlooks communication between people
Rationalism
Maintains that true knowledge about reality derives from the proper use of our reasoning capacities
(intellect, reason or ratio)
Our capacity to think generates ideas and concepts which we cannot arrive at by using our sensory
capacities
Based on the work of Plato
Vs.
Empiricism
Sense experience is the ultimate source of knowledge
The senses are reliable indicators of what reality is like
Based on the work of Aristotle (Plato’s pupil)
,1.2 PLATO’S RATIONALISM
Plato (427 – 347 B.C.):
Famous pupil of Socrates (method of dialectic/cross-examination)
Socrates:
Method of Q&A (intellectual midwifery): assisting others in their philosophizing by asking questions in order
to give birth to new ideas goal: essence of concepts
Not knowing is my only certainty examined concepts to determine their essences (ex. beauty or justice)
Sentenced to death for introducing other new divinities
Plato:
Ontology = the study of being in general ‘why is there something rather than nothing?’
Central issue ancient Greece: what exists and what does not? difference between being and becoming
Parmenides of Elea (510 – 440 B.C.)
Heraclites of Ephese (600 – 540 B.C.)
Both associated with 2 opposing views that set the stage for later developments in antiquity and beyond
Heraclites:
Change (‘flux’ in his words) is the heart of existence
Nothing is, everything becomes view captured in the form of the aphorism ‘panta rei’ ‘everything flows’
methaphor: you cannot step twice in the same river
Nothing is, everything changes
Most people are not able to attain knowledge. Only those few people who are capable of grasping the
hidden and fundamental law (Logos), behind appearances can be said to arrive at knowledge
Parmenides:
Change is the essence of reality people’s senses mislead human beings into thinking that things are
changing all the time
Under all the movement we pick up with our senses, there is a permanent and unchanging reality (the wall is
still the wall, even if the color is changed because of the sun going under)
Everything is, nothing becomes real existence means to be without change
We must rely on reason to discover the unchanging truths about eternal reality
Short:
Parmenides: being is real, change is not rationalist
Heraclites: change is real, being is not empiricist
Empiricists: knowledge is perception
Plato: with the perceived world in constant flux, perceptions and hence knowledge, will vary from moment
to moment, from person to person knowledge ≠ perception
Protagoras (490 – 420 B.C.):
Homo mensura: ‘man is the measure for all things’
Opinion is true to each person which he acquires through sensation no one can ever be wrong about
anything (= empiricist)
Plato: truth and knowledge are about how things really are, not about how they are for me or you.
Therefore, knowledge is not perception.
Plato: the real world cannot be the ever-changing world of appearances, but a supernatural realm which contains
the eternal and perfect Forms (or Ideas) of almost everything influence of geometry (certain knowledge about
ideal figures, not particular instances)
Allegory of human existence allegory of the cave
2
, Allegory of the cave
Prisoners in a cave are chained with their hands and necks so
that their gaze is fixed on a wall. Behind the prisoners is a fire.
Between the prisoners and the fire there is a walkway where
people holding up statues and figures of animals are passing by
(comparison to puppet show). The prisoners have never been
out of the cave and have therefore never seen anything but
these projections on the wall. The prisoners will then mistake
the shadows passing before their eyes for real objects. When a
prisoner is released from his chains, he will first be dazzled by
the fire. It will take some time to convince him that the figures
he sees are more real than the shadows. Once out of the cave,
he is blinded by the sunlight. After a while, he will be able to see the real objects of which the statues and figures,
were copies. He will realize reality once the light of the sun reveals all objects.
Conclusion: human beings mistake appearance for reality.
Plato: the universal Forms are the ultimate realities that ground true knowledge.
Empirical investigation is inadequate for knowledge as it only brings us into contact with a reality that is in constant
Hereclitean flux. Hence, the operation of the senses results in mere belief (doxa), not knowledge (episteme).
Because the Forms belong to a supernatural world we cannot perceive them by using our bodily senses. According to
Plato, we can gain knowledge about this transcendental reality through our capacity for reasoning Plato is a
rationalist.
Nativism = the doctrine that human beings possess innate (inborn) ideas
Closely associated with rationalism
Plato: we are all born possessing all knowledge, the knowledge was lost at birth but if we use our reason
correctly, we are able to remember it all.
o That means there is no new knowledge Plato’s theory about reincarnation
Plato’s theory about reincarnation
The immortal soul belongs to the World of Forms, where it has seen them all, but we forgot about them when our
souls were born into our bodies. Fortunately, the Forms are still accessible through our reason. If we reason well,
we can remember the Forms we saw before birth and thereby come to know the real world.
Dialogue Meno
Explains how knowledge is possessed in the soul’s previous existence in the World of Forms can be recollected.
Dialogue with 3 people: Socrates (the character) defending Plato’s theory, Meno and Meno’s slave. The slave is
poorly educated and knows little about geometry. Socrates intends to show
Meno that the slave could remember mathematical knowledge if he would
reason properly (learning-by-recollection).
[Image shows the square used by Socrates to help the slave reason]
According to Socrates, the slave has figured it out. However, Socrates is leading the slave as he elicits assent to the
geometrical truth. Therefore, the slave does not figure things out himself. Meno, however, is convinced that the
slave remembered all this just by using his intellect.
1.3 ARISTOTLE’S EMPIRICISM
Empiricists argue that the source of knowledge is not reason but sensory experience. Our senses bring us into
immediate contact with the world. The experiences we have when we explore the world must therefore constitute
the foundation of knowledge.
Artistotle addressed subjects such as physics, biology and politics. For scientific progress to be made possible, we
must leave abstract theorizing and turn to the empirical facts of nature.
Aristotle:
3
