Outline
Introduction to Scientific
Thinking
The importance of science
Defining science
Recipes for science
Chapter 1: What Is Science?
The importance of science
A practical concern: global warming
Paris Agreement signed in 2016: keeping temperature rise below
2° Celsius in this century
Increasing concentrations of greenhouse gases (mainly CO2 and
methane) increase the earth’s temperature.
Why so serious?
Temperature rise changes the climate. As a result, some animal
and plant species go extinct and ecosystems collapse, extreme
weather becomes more frequent. Risks of drinking water
shortage, more frequent hurricanes, floods and droughts. As a
result, social conditions destabilize.
The importance of science
Increasing concentration of CO2 was first observed by C. D.
Keeling in 1958. It is called the Keeling curve.
Chapter 1, Figure 1.2
The importance of science
The Keeling Curve
May 30th 2017 CO2 recording: 409.39
Human activities (mostly the burning of fossil fuels) are a major
reason of rise in temperature.
410
400
CO2 concentration (ppm)
390
380
θ=
69
We know all about this because of science.
Physics: How heat radiation works
Physical chemistry: How CO2 in atmosphere traps heat
(greenhouse effect)
370
360
350
340
Dr. Charles Keeling
(1928–2005)
Annual Cycle
330
320
310
θ = 44
1960
1965
1970
Jan Apr Jul Oct Jan
1975
1980
1985
1990
1995
2000
2005
2010
2015
Years recorded at Mauna Loa Observatory
The importance of science
Public understanding and acceptance of climate science and
global warming are still poor.
Understanding how science works and how it produces
trustworthy knowledge are important for citizens in a
democracy.
The importance of science
Why is science important?
Limitations of science:
Science aims to produce knowledge.
In its traditional definition, knowledge is justified true belief.
A belief is justified if you have good reasons for believing it.
Justified beliefs may or may not be true.
True beliefs may or may not be justified.
Science cannot replace non-scientific intellectual pursuits (like
literature or philosophy).
Basic research: Aiming knowledge for its own sake; to explain
how things work in nature
Applied research: Aiming knowledge to develop products that
will improve the human condition
Science cannot decide by itself what should be done about
climate change. In addition to scientific knowledge, political
decisions are needed.
Science does not deal with the supernatural or with miracles. So,
science is silent with respect to theological questions. (perhaps
debatable)
Defining science
Defining science
Climatology is a science whereas astrology is not. Therefore, we
should trust climatologists but not astrologists.
1. Defining science by its history:
What kind of activities have been called science in the past?
Why? What is science and why does it deserve our trust?
Scientia: Knowledge
We attempt to demarcate science from pseudoscience so that we
know whom to trust as experts, what to teach in schools, which
ideas about the world to take seriously, etc.
Scientific revolution (1550-1700): The birth of modern science
Copernicus, Galileo, Newton, etc.
It is not easy to give an exceptionless definition of science. We
will look at three different attempts.
Defining science
One defining feature of the scientific revolution is the transition
from the geocentric to the heliocentric view of the cosmos.
In 1543, Copernicus presented the heliocentric view. At that
time, the two views were not clearly superior to each other.
Research by Kepler and Galileo changed that.
Kepler suggested elliptical rather than circular orbits.
Using a new telescope, Galileo observed moons orbiting Jupiter,
which suggested that the earth is not the centre of the cosmos
around which everything orbits.
Perhaps science can be defined as everything that has descended
from the Scientific Revolution.
Before that, the Islamic Golden Age of science (8th-13th
centuries): Razi, Kharizmi, Haytham, Biruni, Ibn Sina, etc.
Defining science
One problem with this suggestion is that the Scientific
Revolution included philosophical and theological ideas which
we do not consider scientific today.
During the Islamic Golden Age, science, philosophy and
theology were not distinguished at all.
Another problem is that disciplines such as linguistics,
economics, etc. were not recognized as science during the
Scientific Revolution.
Both the subject natter and the methods of science today differ
from those during the Scientific Revolution.
Defining science
Defining science
2. Defining science by its subject matter:
What do scientists investigate?
Natural phenomena are occurrences observable either directly or
with the help of technology.
One problem with this suggestion is that scientists investigate
almost everything: quarks, DNA, emotions, institutions, etc.
Natural explanations invoke only natural phenomena to explain
other natural phenomena (methodological naturalism).
What do all this subject matter have in common that is not
shared by pseudoscience? Probably nothing.
(Ontological naturalism: Nothing apart from natural phenomena
exists.)
Perhaps what distinguishes science is that it attempts to provide
natural explanations to natural phenomena (unlike religion,
literature or art).
Supernatural phenomena are not governed by natural laws and
might be unobservable.
Defining science
Defining science
«Science cannot tell us anything about supernatural phenomena
such as miracles, ghosts. They are outside the realm of science.»
This is also debatable. (see also Exercise 1.16, p. 30)
3. Defining science by its methods:
How do we go about doing science? Which general principles do
we follow?
Still, pursuit of natural explanations for natural phenomena is
not something unique to science. When trying to solve a murder
case, a police detective does the same thing.
Scientific investigation involves empirical evidence.
Evidentialism: Whether a belief is justified is determined by how
well it is supported by evidence.
Falsificationism: Scientific ideas are tested against evidence that
might potentially refute (falsify) them.
Naturalism is an essential feature of science but it is not enough
to demarcate science from non-science.
Defining science
Defining science
There are two aspects to falsificationism:
Two other characteristics of scientific inquiry:
i) Any scientific claim should be falsifiable. You should have an
answer to the question: «What evidence, if obtained, would
falsify your claim?» If no evidence could potentially falsify it,
your claim is not scientific. True claims can still be falsiable:
False, falsified and falsifiable are different concepts.
Quantitative analysis: Using mathematical techniques to
measure, describe or summarize natural phenomena
ii) Any scientific claim, however plausible, should be abandoned
if there is sufficient evidence that falsifies it: openness to
falsification. This is related to honesty: You should accept defeat
when your claim is falsified.
Defining science
The nature of science (see Table 1.1, p. 27):
Aiming to generate knowledge (scientia)
Historical basis in the Scientific Revolution
Commitment to (methodological) naturalism
Empirical investigation (rather than pure thinking)
Evidentialism
Falsifiability (claims) and openness to falsification (scientists)
The use of mathematics
Social structure
The previous example of climate change is consistent with these
features.
Science has a social and institutional structure: Scientific inquiry
is not an individual endeavour. Science relies on communities of
many people working on similar projects. They sometimes
cooperate and sometimes compete with each other.
Defining science
Astrology is a typical example of a pseudoscience.
Its claims are usually not falsifiable because of vague
predictions.
Basic principles of astrology are inconsistent with
well-understood phenomena in physics, biology and psychology.
More recent examples of pseudoscience (or science denial) are
climate change denial, anti-vaccination campaigns, and
creationism and intelligent design (denial of evolutionary
theory). They are inconsistent with our current scientific
understanding of physics and biology.
Recipes for science
«The scientific method is a myth»:
There is no single scientific method.
Instead, there are «recipes» used by scientists. Like good
cooking, good science is a highly variable and creative process.
Descriptive claims: How things in fact are and why they are that
way.
Normative claims: How things ought to be (with reference to a
norm or value).
How humans actually reason, vs.
How they should reason (norms of rational thinking)
Recipes for science
Recipes for science
Flaws in human reasoning:
Scientific method protects us from common flaws of reasoning
Confirmation bias: We seek information that fits our beliefs and
avoid information that would challenge them. Thus, we avoid
the potential falsification of our favoured beliefs.
Observer-expectancy effect: The scientist’s expectations
unconsciously influence how the experimental subjects behave.
Example: Clever Hans, investigated by Pfungst
Condition 1: using blinders on Hans
Condition 2: using an ignorant questioner
Result: Hans cannot answer correctly; body language
Recipes for science
Norms of science protect us from flaws of reasoning.
2. Norms of the scientific community
1. Norms of individual investigators
Science is a collaborative effort. Individual scientists and
communities of science should be able to trust each other:
Be trustable and trust others
Plagiarism: Presenting someone else’s work (findings, ideas,
etc.) without giving credit to that person, creating the impression
that it is one’s own work
Faking data: Presenting non-existing findings as real
Conflicts of interest: Personal or financial gains can influence
research findings. Any potential conflict of interest should be
disclosed by the scientist: transparency
But not blind trust: critical evaluation of research findings
Replication: Doing the same study to see if you can get the same
results
Peer review: Research findings are checkef for accuracy by other
scientists before they are published in scientific journals
Recipes for science
Methods in science:
Scientific method also protects against flaws of reasoning
Three steps:
Formulation of hypotheses
Deriving testable predictions (expectation) from hypotheses
Testing predictions by comparing them to actual observations
Beyond simple observations, scientists make theoretical claims
about entities that are not directly observable. Theoretical claims
aim to explain observable phenomena.
Example: All salt dissolves in water.
Recipes for science
Observations:
Passive observation vs. observation after intervention
Example: Sage and mint leaves smell similar unless you crush
them.
Intervention requires doing an experiment: Chapter 2
Recipes for science
Science is concerned with a special kind of claim called a
hypothesis. It is a guess about what the world is like. It is not yet
known whether it is true, so it needs to be tested.
Hypotheses may be formulated before any observations are
made using imagination, or they can be formulated on the basis
of preliminary evidence or background knowledge.
Expectations (predictions):
What should we observe if the hypothesis is true?
Example: What should we observe through the telescope if there
is a black hole over there? (A black hole cannot be directly
observed.)