Philosophy of Science
Summary
Lecture 1
Philosophy of science: Critical reflection on what science is, does, and how it generates knowledge
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
~ What exactly is science?
As an academic, you should be able to explain why psychology is classified as a science.
This requires knowledge: You need to know the different answers that have been given in the history
of thinking about science to the question ‘What is science?’.
Besides having the knowledge, you also need to have the skills to reflect on questions like:
~ Is psychology a science? / Is it justified to call a psychology a science?
~ Is it justified that science has the monopoly on acquiring knowledge?
Knowledge and skills also serve another goal: building of character (understand why you are doing
this/seeking knowledge/being a therapist/etc.). By thinking critically about science, and about the
scientific status of psychology, the gained insight in psychology as a science might make us better
psychologists.
Epistemology = Theory of knowledge
Epistemology asks three questions:
~ What is (certain) knowledge?
~ How can we justify that knowledge?
~ What is the source of knowledge?
Traditionally there are two views:
~ Rationalism: real knowledge is derived from the ratio (reason)
~ Empiricism: real knowledge comes from sensory experience
Skepticism: ‘perhaps the conclusion must even be that we do not know anything at all, and never
will.’ Skepticism is all about the idea that you cannot be certain of anything.
Socrates in the market square asking difficult questions is an example of skepticism.
Rationalism
General claim of rationalism is that real knowledge stems from our reason/ratio. Rationalism also has
an associated claim: there is innate knowledge (=nativism).
Plato:
Plato’s rationalism is only one specific kind of rationalism, and therefore not a good definition of
rationalism in general.
He argued, to learn something is to remember (=anamnesis). So, in other words, there is no new
knowledge. You do not really learn anything, but simply remember.
Plato believed in reincarnation: before you were born, you had all real knowledge, which you lost
when you were born.
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,He made a distinction between episteme (knowledge of how the things are) and doxa (opinion about
how the things are).
Knowledge/episteme is defined by Plato as justified and true belief. This means the world is actually
the way the mental state depicts it (the true part), while you’re able to explain how you know it is
true (the justified part).
A skeptic would say you are never able to explain how you know it is true, so as a true skeptic you
would never make a statement about the world.
Heraclites said that everything is changing/flux (=Panta rhei). If in our world (the world we perceive
with our senses) everything changes constantly, then nothing is. This would mean we can only
acquire doxa, not episteme, as we cannot make claims anymore about things that are, when they’re
constantly changing (and that would amount to skepticism).
Plato responds to Heraclites with the idea that there is a world where things are not changing, but
where things are.
World of ideas/forms: a world in which things do not change.
Your soul belongs to this world of ideas, and your soul has seen these ideas (forms/things). When
your soul is born in your body, that is when you forget.
Anamnesis: acquiring knowledge is to remember these ideas
Plato’s allegory of the cave: people chained in a cave see shadows of things and perceive the
shadows as the real thing, while the real deal is in another world (world of ideas).
Meno: Plato’s book that is written in dialogue, with Socrates and Meno as characters. Socrates
explains the world of ideas to Meno, a landowner with slaves. He does this by asking one of the
slaves to double the surface of a square. The slave gets it wrong at first, but Socrates (fictional)
corrects the answer, and the slave then suddenly ‘remembers’ it. The dialogue is unacceptable, as
Socrates (fictional) puts the slave of Meno words in the mouth to get a point across.
This kind of rationalism is very extreme.
Empiricism
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
use another sense). The central claim thus is that you gain knowledge from the experiences you
have. The associated claim is then that there is no innate knowledge, when all knowledge comes
from experience via perception.
Take note! There is a difference between empiricist and empirical.
Empiricist refers to empiricism, which is the opposite of rationalist.
Empirical refers to the scientific method, which uses observational or experimental data to infer
conclusions about the world. Empirical is the opposite of purely hypothetical.
Aristotle:
Was Plato’s student, but rejected Plato’s two-worlds theory: there is only one world, and that is the
one we can perceive with our senses.
This also implies a rejection of innate ideas: Man is a tabula rasa (= a blank wax tablet), born without
knowledge.
Aristotle was the founder of the Lyceum, where he taught while walking (peripateo in Greek). Hence
Aquinas later called the empiricist principle peripatetic principle: Nothing is in the intellect which
was not first in the senses. Aquinas’ interpretation of Aristotle is partly correct, as Aristotle can
rightly be called an empiricist as the key to knowledge is sensory perception. However, Aristotle does
have some rationalist elements in his empiricist epistemology:
He argues for universal concepts. While, according to Plato, the idea Chair is an entity existing in the
world of ideas, Aristotle rejects this idea, and accepts only the existence of concrete, individual things
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, (the individual chair). Aristotle called the empirical procedure by which we move from the concrete
to the universal induction (or epagoge in Greek).
Induction is concluding, based on observation of some cases (but not all) in which A was also B or
was followed by B, that A is always B or is always followed by B. However, on the basis of observation
alone one cannot tell that the abstract general proposition (such as ‘all humans are mortal’) is true, it
is just a correlation. Yet Aristotle did believe that the proposition would be necessarily true, so is
knowledge.
In order to solve this problem, induction is therefore only a first step. A second step is needed.
Through our unfailing intellectual capacity of the mind we can understand that abstractions (such as
‘all humans are mortal’) are necessary truths. This is intuitive induction (=understanding), which is a
rationalistic element in his epistemology. (Aristotle was only afterwards classified as empiricist, and
never claimed to be one himself).
When Aristotle had found a general statement, he was not very critical towards that statement. That
is understandable, as he thought he had established via intuitive induction that the statement was
true.
The role of Aristotle in the late Middle Ages:
In the Middle Ages, the Catholic church had a lot of power. Issues relating to knowledge and reality
were resolved either by quoting the bible or by quoting Aristotle. So there were two paths to the
truth, revelation and using your good sense. However, Aristotle lived pre-Christ. Thomas Aquinas
tried to unite Christian teaching with the pagan ideas of Aristotle (‘the Philosopher’). He argued what
the Bible said and what Aristotle said are the same, but worded differently.
An example: Aristotle had a theory about matter and form. Matter (such as a piece of marble) is
potentially something (a statue). The shape makes something that actual thing, such as the statue.
The statue can break again, so it is a process of creation and decay (again a view of flux/panta rhei).
Aquinas argued that God has put this process of creation and decay in motion.
Aristotle’s unmoved mover: the first cause of a chain of causal reactions, which Aquinas argues is
God.
By coupling Aristotle to the bible, one could not just simply disagree with Aristotle, because attacking
him meant attacking the bible. This had consequences for the development of search for truth.
Aristotle did no experiments, because he thought that they would not teach us anything about the
natural world. He used the method of observation. By manipulating, we make the world go against
the natural ways of things and as such we do not learn anything about the natural world.
So in the Middle Ages, both philosophy and science (there was really no difference back then) came
more or less to a halt.
Lecture 2
Francis Bacon had no problem with questioning the Aristotelian worldview. Bacon argued that we
should use experiments to learn about the natural world.
The new method:
a) We need to abandon our epistemic prejudices
b) We need to use the empirical method
c) We need to use induction
a) Epistemic prejudices:
People have persistent epistemological biases (Bacon speaks of idols or false conceptions), which
stand in the way of acquiring knowledge, so we need to be wary not to use these prejudices.
It involves the following biases: idols of the tribe, idols of the cave, idols of the marketplace, and idols
of the theatre.
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