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ToK: Natural Science

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Chris Kirby

on 24 September 2013

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Transcript of ToK: Natural Science

photo credit Nasa / Goddard Space Flight Center / Reto Stöckli
Natural Science
What is an 'experiment' in science? Think back to a time when you conducted an 'experiment' in physics, chemistry or biology. What did you do and why did you do it? What did you learn? Was it possible for you to claim that the experiment worked or did not work? What does it mean to say an experiment worked?
Opening Question:
Stage 1: Observation
Stage 2: Information
Stage 3: Generalization
Stage 4: Theory
Stage 5: Explanation and Prediction
The Basic Scientific Method:
The basic scientific method requires both kinds of logic: inductive and deductive
Stage 1: Observation
Stage 2: Information - using induction leads to...
Stage 3: Generalization
Stage 4: Theory - using deductive logic leads to...
Stage 5: Explanation and prediction
Problem #2: The Logic Problem/The Problem of Induction
Created by Karl Popper
Sidesteps the problem of induction
Scientists do NOT begin by making basic scientific observations - rather, they begin with an IDEA or informed theory based on previous theories
Using this idea they create a hypothesis, but they DO NOT assume their proposition is true
The hypothesis is then tested with the sole aim of proving it FALSE
The Scientific Method #2
Can you falsify the following statement:
People become mass murderers because of certain traumatic events they experienced in childhood.
More controversially, what does this say for hypotheses from disciplines such as psychiatry?
Which seems a more accurate depiction of how science progresses?
is an obsession of the 20th and 21st centuries
is a provider of facts
is reliable, precise, objective, testable, and self-correcting
uses the scientific method
attempts to describe the physical reality of the world we live in
Natural Science...
attempts to study the phenomena of the physical universe
has four broad categories....which are?
Natural Science...
Natural Science: 4 Broad Fields
Earth Science
Aerobiology: nature/distribution of pollen, spore, etc
Agrobiology: soil and plant nutrition
Astrobiology: extraterrestrial life
Bacteriology: bacteria
Biochemistry: chemical processes in plants
Biometry: stat methods in biological investigations
Biophysics: applying the laws of physics to organisms
Cybernetics: control and communication within organisms
Further Specialization is Possible:
The basic scientific method begins with observation
At least 3 factors influence the information we gather through observation:
Perceptual Problems
The success of scientific undertakings depends on the reliability of our senses - and we've already discussed how unreliable those can be
Problems with the Basic Method: Observation
Predictions made using this model can be accurate, and in practice this method works - MOSTLY
Problem #2: The Observation Statement
Observations have to be described using language - there has to be an observation statement
Because our observation statements use language, they assume theories embedded in our language
EX: The highest tide was recorded at 14.42.
What assumptions are made in that statement?
Problems with the Basic Method: Observation
The highest tide was recorded at 14.42.
That there is such a thing as a tide
That there is such a thing as a HIGHEST tide (which implies a LOWEST tide as well)
That water has a HEIGHT
Problems with the Basic Method: Observation
However neutral the observational statement attempts to be, the language used in the statement invariably influences the neutrality
The Choice of What is Observed
What influences what a scientist CHOOSES to observe? Money? Society? Trends?
Some scientists can have their observations influenced by random accidents or chance
Problems with the Basic Method: Observation
The use of deduction between stages 4 and 5 is no problem.
The use of induction between stages 2, 3 and 4 IS a problem
Problem #2: The Logic Problem/The Problem of Induction
Problem #2: The Logic Problem/The Problem of Induction
Science is looking for certainty, but we have previously established that induction CAN'T GIVE US certainty
Deductively, we could then argue:
1. The scientific method demands certainty.
2. Inductive logic can never be certain
3. Therefore, the scientific method cannot use inductive logic
1. It Works!
Science delivers - medication works, we can pretty much predict the tides
It may not be perfect, but it's pretty good, and right now it's the best we have
A PROBLEM with this argument is that it uses a generalization to defend induction - an inductive argument cannot be used to defend induction
Some solutions to the problems:
2. Probabilism
Laws of nature may not be certain, but they PROBABLY are
The more observations we make, the more information we have confirming what we know, the more likely it is to be true
Some solutions to the problems:
3. Denial
The basic scientific method is not REALLY the basis of scientific knowledge. The real model is different. If the real model doesn't use induction, then the problem of induction doesn't exist.
Some solutions to the problem:
The Falsification Model
State conditions under which hypothesis would be disproved (falsified)
Test hypothesis with the aim of falsifying it
If hypothesis is not falsified by the experiment, it can be accepted provisionally, waiting for future tests
If hypothesis is falsified, it must be modified or rejected
Popper's Metaphor for Science
Science is like a building built on piles in a swamp - without any natural or given base. We cease driving piles down when we have support to carry the structure - NOT because we have reached firm ground.
Observation is just as important in Popper's theory as it is in the Basic Scientific Method
However - note where observation is placed
This model is STILL subject to the problem of observation
However, it is NOT subject to the problem of induction. No induction is needed in Popper's model; thus no inductive logic is used.
Observation and Falsificationism
1. Certainty
If one single false example shows the hypothesis to be unacceptable, it is unsatisfactory - it CANNOT be scientific
Therefore, a certainty is achieved - the certainty that there is no certainty!
Advantages of Falsificationism
2. Scientific Relevance
Falsificationism can be used to distinguish scientific, valid hypotheses from non-scientific hypotheses
A hypothesis that cannot be falsified CANNOT be scientific
Ex: CAN BE tested and falsified
Earthquakes under the Pacific Ocean always occur in June
Ex: CANNOT be falsified
There will, or will not, be earthquakes under the Pacific Ocean in June.
Advantages of Falsificationism
3. Scientific Growth
Falsificationism encourages the growth of scientific knowledge
Science progresses when hypotheses are falsified and new, better theories replace them
If you cannot at least theoretically falsify a hypothesis, then it will not lead to new knowledge
Advantages of Falsificationism
2 Examples suggest that Popper's scientific method is NOT an accurate description of science:

Copernicus TRIED to falsify the Ptolemaic view of the universe, but it took CENTURIES before his ideas were accepted
Newton's laws of gravity and motion were accepted and applied for centuries - but some of his theories were falsified soon after he published them. It took Einstein in the 20th century to show that they needed to be revised.
Is Falsification Historically Accurate?
Is Popper's view of scientific discovery advantageous? Is it practical? Is it realistic?
Thomas Kuhn argues against BOTH the basic scientific method AND falsificationism
Kuhn argues that science only progresses through revolutions
a scientific revolution is one in which one system is replaced, dramatically, by another system
Scientific Method #3: Scientific Revolutions
Normal science paradigm: scientists engaged in 'clean-up' work
Crisis: The paradigm fails
New Paradigm
New paradigm accepted as normal science
Normal science paradigm
Kuhn's Revolutionary Science Method
Smooth Progress
Given what you now know about paradigms, what does this say about our view of truth and knowledge?
Some reject Kuhn's ideas because they seem to regard truth as relative. Do you agree?
Evaluation of Kuhn's Theory
Yes - if we limit ourselves to only the physical, natural world
There IS a more absolute area of knowledge in which justification is absolutely independent of observation. What is it?
Is science the most reliable area of knowledge? Is it the BEST justified true belief?
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