P.B. Medawar. Advice to a young scientist. Basic Books. 1979.

1

Medawars Experimentation Models Computer
Science

• P.B. Medawar. Advice to a young scientist. Basic
  Books. 1979.

2
Peter Medawar

• Nobel Prize for Medicine 1960
• 1915- 1987, born in Rio de Janeiro, son of a
  Lebanese business man who was a naturalized
  British subject.
• Bachelors degree from Oxford in 1932.
• Worked on tissue grafts and transplants

3
Solutions

• Solving a problem simply means representing it so
  as to make the solution transparent.
• 
  Herbert Simon
• Research is the art of the soluble.
• 
  Peter Medawar

4
How Do we look at things?

• El Greco test

5
Medawars Experiments and Discovery

• Four kinds
• Baconian (observe)
• Aristotelian (effect)
• Galilean (hypothesis)
• Kantian (thought)
• What does it mean to do experiments in CS?

6
1. Baconian Experimentation

• Find truths by careful examination of things as
  they are
• Compilation of facts
• Contrived performance rather than natural
  occurrance
• No control group, no theory
• Examples
• Magnetising nails
• Static electricity in silk
• Trying things out or mucking about

7
Baconian experimentation in CS

• Early IR
• KWIC/ KWOC indices
• Zipf distribution
• Counting word occurrences and distributions

8
2. Aristotelian Experimentation(John Glanville,
Royal Soc. 1636-84)

• Demonstrate some preconceived idea
• Ring a bell before giving the dog his dinner
• Effect without theory
• Examples of X
• CS??

9
Aristolelian Experiments in CS

• Eliza
• Bob
• Pop up ads
• IR data visualizations

10
Post hoc, ergo prompter hoc

• Psych Why do you flail your arms around like
  that?
• Patient Keeps the wild elephants at bay.
• Psych But there arent any wild elephants here.
• Patient Thats right. Effective, isnt it!

11
4. Kantian Experiment

• Thought experiments
• Examples
• non-Euclidian spaces
• Parallel lines that meet
• Lets look at that differently

12
Kant meets CS

• N-dimensional vector spaces
• Shneiderman data walls
• Hypercube
• Web graph
• Data visualization

13
3. Galilean Experimentation

• Expose hypothesis to a test
• Dropping of canon balls off Pisa tower to test
  his hypothesis of gravitational acceleration
• Leads to the null hypothesis
• Experiments can not really prove anything!
• Best you can do is refute the null hypothesis
• I.e., that you have done better than wild good
  luck
• Looking at results of differences of observations
• Be prepared to take no difference as an answer

14
Hypotheses

• I cannot give any scientist of any age better
  advice than this the intensity of the conviction
  that a hypothesis is true has no bearing on
  whether it is true or not.
• Medawar

15
Galilean Experimentation in CS

• Algorithm efficiency
• Algorithm effectiveness
• User preference
• Etc

16
Not withstanding

• Simpsons Paradox
• 2 data sets -gt separately support a conclusion
• BUT the union supports the opposite conclusion
• Will Rogers Phenomena
• In a patient study, it is possible to transfer a
  patient from one group to another and improve the
  statistics of both groups
• Mark Twains Observation
• Lies, damned lies and statistics!

17
How to be prepared to do research I

• Mastering the literature
• Too much
• Confine the imagination
• Psychological substitute for research
• Too little
• Make an idiot of yourself
• Mix some eclectic breadth with selected depth
• Eg. ACM Communications and IJHCI

18
How to prepare II

• Get on with it
• Get results
• Repeat others work
• Try variations
• Try other data
• Join the discussion
• When I tried that
• I got exactly the same results when I
• I agree, for this purpose x is better then y

19
How to prepare III

• Follow the art of the soluble
• Start with a soft underbelly problem
• Quantification of vague phenomenon
• Isolating factors
• Selecting feature sets
• To quantify is not to be a scientist,
• but it does help. (Medawar)

20
Also part of the Scientific Process

• Devising hypotheses that can be tested in a
  practical manner
• Imaginative guesswork
• Exercise of common sense
• All experimentation is a form of criticism
• Having the right slot in your mind to put a new
  observation or idea
• Good luck counts
• Accept flux. Science as a Maoist microcosm of
  continuing revolution.

21
(No Transcript)