Transcript what_is_science_cu

What is Science?
Human Biology
1/18/16
• … a tool that allows us to get and organize
knowledge of the physical and natural world and
society through a well-established method.
-OSU grad student
• … anything we do that employs the scientific
method… Thus, science could be used to describe
anything, from experimenting which spice is best for
the soup or theorizing how black holes function.
-OSU grad student
• … a way of thinking; an analytical mindset. It is a
systematic way to answer questions or solve
problems.
-OSU grad student
• A process whose essential characteristics are 1)
guided by natural law; 2) is explanatory by natural
law; 3) is testable against the empirical world; 4) is
falsifiable.
– William R. Overton, U.S. District Judge in a ruling prohibiting
an AR law giving balanced time for creation-science and
evolution, 1982
• The observation, identification, description,
experimental investigation, and theoretical
explanation of natural phenomena.
– American Heritage Dictionary
• Above all it is a methodology for acquiring testable
knowledge about the natural world.
– Stephen Jay Gould
• A process: methodology for generating new
knowledge based on cycling the following
progression: observation, explanation,
prediction, test, results, conclusion.
A product: new knowledge with the following
characteristics: it is cumulative, knowledge
expanding, explanatory, predictive, systematic,
testable, verifiable, tentative, self-correcting.
-OSU professor
• OR…
… a way of baffling the uninitiated with incomprehensible
jargon. It is a way of obtaining fat government grants. It is a
way of achieving mastery over the physical world by
threatening it with chaos and destruction.
Scientific Method
• Observation
• Hypothesis
• Prediction
• Test of prediction
Scientific Method
Test of prediction
– Treatment versus control group
• Independent vs dependent variables
• “control” confounding variables
– large sample size
– Cause and effect conclusions
Scientific Method
• Types of (dependent) variables
1. Categorical (color, sex)
2. Discrete (number of fingers or leaves)
3. Continuous (weight, height)
• Appropriate ways to graph the above?
Scientific Method
Test of prediction
– Hypothesis vs null hypothesis
– Statistics is a tool
Scientific Method
3 Criteria of a good prediction
1.Improbability
2.Deducibility
3.Testable
Scientific Method
• Prediction is true – reject the null hypothesis
– Conclude: data are consistent with the hypothesis
– NOT: data prove the hypothesis
• Or prediction is false
Scientific Method
• Conclusions are published
• Conclusions are challenged by others
Scientific Method
Think about the Scientific Method
Think about bacteria: what do you know about
bacteria? Where does it occur? What does it do?
What does it need to grow?
• In groups of 3-4, list some observations about
bacteria
• Generate possible explanations (hypotheses) that
could explain your observations
Is Science Objective?
• “The objectivity of SCIENCE, imperfect as it is, is
not a function of the objectivity of SCIENTISTS. It
is a function of the “logical” rules of the game.
These are embodied in the specification of a good
test, and thus in Conditions 1 and 2. So there is
no reason why scientists should not try to justify
their hypotheses and be very disappointed if they
are refuted. The rules of the game ensure that
the harder one tries to get a good justification,
the greater the risk of refutation – unless the
hypothesis is indeed on the right track.”
– R.N. Giere, 1984. Understanding Scientific Reasoning
Science and Society
• What obligations does Science have towards
Society?
– Tax dollars support a lot of scientific research
– Ethical questions
Deductive Arguments
• Moves from the general to the specific
• If the premises are true, then it is impossible
for the conclusion to be false (valid).
Examples of Deductive Arguments
All CU students are mammals.
All mammals have lungs.
Therefore, all CU students have lungs.
• Valid, true premises; sound
If it is snowing, then CU cancels classes.
It is snowing.
Thus, CU cancels classes.
• Valid, false premise; unsound
Inductive Arguments
• Move from the specific to the general
• Strong: if premises are true then it’s probable
that the conclusion is true.
• Cogent: an inductive argument that is strong and
has all true premises
Examples of Inductive arguments
Bill is a partier.
Most business majors are partiers.
Thus, Bill is probably a business major.
• Strong but not necessary support for conclusion
Deductive vs Inductive
Which tends to expand knowledge?
Which tends to preserve truth?
Which has valid, sound arguments?
Which has cogent, strong arguments?
Deductive vs Inductive
Which tends to expand knowledge?
– inductive
Which tends to preserve truth?
– deductive
Which has valid, sound arguments?
– deductive
Which has cogent, strong arguments?
– inductive
3 Types of Scientific Inquiry
1. Discovery science
– relies upon making observations and descriptions
of nature
– Gathers and catalogs facts via discovery and
detection of patterns
– Asks who, what, where and when
3 Types of Scientific Inquiry
2. Hypothesis-based (theoretical) Science
– Explains and predicts by generating and testing
models
– Involves the proposal of hypotheses or possible
explanations
– Asks why and how
3 Types of Scientific Inquiry
3. Technological Science
– New methodology or process
– Problem solving
Models
• Models are used to represent reality
• They are used to make predictions about reality
Facts, Laws and Theories
• Observation
– Example: it’s raining outside
• Law
– Example: Dalton’s Law
• Theory – a “meta-hypothesis” that explains why
an observation occurs
“A theory is a metascientific elaboration, distinct
from the results of observation but consistent
with them. By means of it a series of
independent data and facts can be related and
interpreted in a unified explanation. A theory’s
validity depends on whether or not it can be
tested against the facts; wherever it can no
longer explain the latter, it shows its limitations
and unsuitability. It must then be rethought,”
– John Paul II. 1997. The Pope’s Message on Evolution.
Quarterly Review of Biology 72(4): 381-383
Deformed and declining populations of
amphibians
Could a parasite be blamed?
Observational study
• Johnson et al. (1999) surveyed ponds to
determine that frogs with deformities were
only present if the parasite’s intermediate
host snail was also present
Controlled lab experiment
Field experiment