Transcript Philosophical Aspects of Science

Philosophical Aspects of
Science
Soraj Hongladarom
Department of Philosophy
Faculty of Arts
Outline
What is science?
 What is scientific methodology?
 Logical structure of scientific knowledge
 How does science differ from other
forms of knowledge?
 Explanation of the success of science
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What is Science?
Standard definition: ‘systematic investigation
of the natural world through empirical
methods and theoretical framework.’
 Problems with the definition
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How can many different disciplines be brought
together under the same heading?
 Physics and biology
 Is psychology a science? Is history a science?
 Why or why not?
 What is meant by ‘systematic’?
Origin of Modern Science
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Aristotle
 Argued
that heavier things fell faster than
lighter things - why?
 Also argued that woman did not contribute
any genetic material to the embryo woman only provided the matter, while the
male provided the form.
 Aristotle’s method - he collected a lot of
samples, but did not experimentation.
Astronomical Systems

Ancient systems
 Some
Greek astronomers argued that the
earth revolved around the sun, so it was
not Copernicus who first brought about the
idea, but the idea did not catch on.
 Ptolemy perfected the system where the
earth is at the center, but he encountered a
lot of problems trying to reconcile the
system with the actually observed data.
Reactions against Aristotle
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Aristotle was the authority of the Church.
Reaction against Aristotle was equal to
reaction against the Church.
Nonetheless, Galileo tried to prove Aristotle
wrong.
This shows the characteristic of modern
science - reliance on the means of knowing
that everybody already has: reasoning and
observation.
Aristotle used that too, but he went too far on
reasoning.
Copernicus

As is well known, Copernicus suggested that
the earth revolved around the sun rather than
the other way round.
 However, he did not observe that the earth
moves around the sun. He simply put forth his
ideas as a hypothesis.
 But his system was much simpler than
Ptolemy’s and as a result was accepted by
astronomers.
 The reason why it faced a lot of resistance
was that it ran against the beliefs at that time
that the earth does not move.
Modern Science

We can pause and look at what modern
science is about.
 Logical structure of science
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Hypothesis
Deductions from the hypothesis
Comparison with actual observed data
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Experimentation
Confirmation or rejection of the hypothesis
The hypothesis becomes a theory when it can
explain a large number of phenomena.
Theory and Law
A scientific theory is a set of statements
serving to explain a number of
phenomena in a systematic and
coherent manner. Deductions from the
theory can be used to test it through
actual observation.
 Examples: Newton’s Gravitational
Theory; Einstein’s Relativity Theory;
Darwin’s Evolution Theory

Theory and Law
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A scientific law, on the other hand, does not
serve to explain phenomena, but succinctly
states how certain phenomena behave.
 Examples: Newton’s three laws of motion;
Boyle’s law on pressure; Einstein’s famous
law -- e = mc2
 Problem - why are there laws in physics and
chemistry, but not in biology?
Scientific Methodology
Many believe that what makes a
science a science is something called
‘scientific methodology’.
 This is believed to be shared by all the
‘scientific’ disciplines, such as biology or
physics, chemistry.

Identification
Form
hypothesis
Test hypothesis
Does the result confirm
the hypothesis?
No – do
further
testing or
reject
hypothesis
Yes – the hypothesis
is confirm. A system
that explains
hypothesis is called
theory.
Problems with the Standard
Picture
What determines the identification of the
problem?
 The picture seems to lead us to think
that scientists are free to identify any
problems that they are interested in.
 But in fact there are a lot of other factors
influencing their choices, most of which
depend on socio-cultural or economic
reasons.
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Problems with the Standard
Picture
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Underdetermination of theories
 Sometimes
the same set of data can
support one or more theories
 Hence it is hard to say which theory is the
true one
How does science differs from
other forms of knowledge?
This is known as the ‘demarcation’ problem
 If we have a standard scientific methodology,
the picture is simple: Whatever follows the
methodology is science; whatever does not is
not.
 But it appears that different sciences follow
the methodology quite differently.
 Biology and astronomy consist mostly of
observation and classification; whereas
chemistry and physics involves a lot of
experimentation.
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Role of theories
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Biology does not rely as much on theories
and laws as do physics and chemistry.
 Some believe that all scientific disciplines can
be reduced to physics, which is regarded as
the most basic.
 But can we use physical theories to explain
biological phenomena?
 The point is that even within science there
are differences.
Karl Popper
The philosopher who advocated the
demarcation problem is Karl Popper.
 His idea is known as ‘hypotheticodeductivism’ -- all scientific knowledge
proceeds through setting up hypotheses
and deduce the consequences. When
the test result does not conflict the
hypothesis, it is accepted as knowledge,
but when it’s not it is rejected.
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How does astronomy differ
from astrology?
Both used to be the same, until
astronomy became ‘scientific’ in the
17th century and distanced itself from
astrology.
 But where exactly are the differences?
 According to Popper, astronomy follows
HD, while astrology does not.
 But astrology can follow HD too!
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HD in astrology
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Hypothesis: Those born under the influence
of Venus are pretty and love sex.
Deductive consequence: Sutheera is born in
May, which falls under Venus.
Therefore, she should be pretty and love sex.
Through observation, Sutheera is really pretty
and she does love sex a lot.
Therefore the hypothesis is confirmed and
astrology is indeed scientific.
HD in astrology
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Hypothesis: Those who are born under the
influence of Jupiter tends to be happy and
optimistic.
Deductive consequence: Pornthep is born in
December, which falls under Jupiter.
Therefore, he should be happy and optimistic.
However, observation shows that he is
anything but happy and optimistic.
Therefore, the hypothesis is contradicted.
But this does not mean that astrology is not
scientific, because there may be other
influences that can explain why this happens.
The demarcation problem
Popper’s demarcation attempt thus
faces a lot of problems. The idea of HD
does not seem to work well.
 We are still searching for the real
demarcation that separates science and
non-science.
 Perhaps the difficulty lies in the fact that
we are still unsure what in fact is
science from the beginning.
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Explanation of the success of
science
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Another way to demarcate science from other
forms of knowledge is that science seems to
be successful.
 So success may be the determining factor.
 But then there seems to be a change in the
rules. Earlier the rule seems to be that
science gets at the truth, whereas other forms
don’t.
 But Popper’s problems prompts those who
want to defend the demarcation to turn to
success. Problem is: Success is not the same
as truth.
Success and truth
There are many indications that
success and truth need not be the same
-- a statement can be successful without
being true.
 But if that is the case, then to argue for
demarcation by relying on success is
changing the rule.It is as if one admits
that science does not always lead to
truth.
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