lecture 1 - the basis for the scientific method

7/30/2019 Lecture 1 - The Basis for the Scientific Method

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Lund University, Lund, Sweden

Department of Water Resources Engineering

On the importance of the wordErgo

Intro to some of fundamentals in the Scientific

Methodology

Presentation at TPU October/November 2012


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The six virtues of science

About the value of arguments

Deduction and Induction

Occams razor Bayes rule

The art of making 1 + 1 = 3

The Menu


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The Six Main Virtues of Science/Rationality:

Curiosity (if you dont ask questions you will never get any answers)

Scholarship (study many sciences and absorb their power as your own)

Realism/Humility (to be humble is to take specific actions in anticipation ofyour own errors)

Empiricism (the roots of knowledge are in observation and its fruit is prediction)

Precision (better be precisely wrong than vaguely right)

Argument/Rational reasoning (Normatively, any argument relieson an evidential base which consists of supporting data whose relationship to the claim iselaborated through the warrant, which in turn, may be dependent on a set of underlyingassumptions)

Fundamentals in the Scientific Methodology


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< Statement or Proposition >

[BECAUSE]

Karena Omdat

Porque

Fordi

Because/Therefore

Ergo



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Possible arguments:

The Earth is Flat as a Pancake!

The Earth is Flat as a Pancake BECAUSE the pope

dictates so and will kill me if I say otherwise....

The Earth is Flat as a Pancake BECAUSE I cantunderstand why it could be spherical....

The Earth is Flat as a Pancake BECAUSE my eyes tellme that it looks flat....



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Picture from a 1550 edition of On the Sphere ofthe World, the most influential astronomytextbook of 16th century Europe

The Earth is flat because:1. The space agencies of the world are involved in an

international conspiracy to dupe the public for vast profit2. The impossibilities of holding unsecured objects in place

on a curved surface


Aristotle (384322 BC), the famous Greek

natural philosopher, reports thatmathematicians had allegedly evaluatedthe dimension of Earth at 40.000 stadia,adding:From their supposition, it followsthat the shape of Earth must be a sphereand also that its size be small relative tothe distance of other celestial bodies.

Images of the earth how it wasseen (by the catholic church)during the dark middle age (1000-1500 BC)...


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The two main approaches in modern science:

Deduction (general theories predictions):inference by reasoning from generals toparticulars, or the process of deducing from

something known or assumed

Induction (observations general theories): theprocess of inferring a general law or principle

from observation of particular instances...

Sherlock Holmes (The Sign of Four):I never guess. It is a capital mistake to

theorize before one has data. Insensibly onebegins to twist facts to suit theories, instead

of theories to suit facts.



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Occams Razor (looking for the simplestexplanation with the fewest assumptions)

"We are to admit no more causes ofnatural things than such as are both trueand sufficient to explain their

appearances"

"If you have two theories that bothexplain the observed facts, then youshould use the simplest until moreevidence comes along" KISS...!

Keep It Simple, Stupid!

"The explanation requiring thefewest assumptions is mostlikely to be correct"



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Bayes Rule (accummulating (uncertain) evidence againstan (uncertain) hypothesis)

The essence of the Bayesian approach is to provide:a mathematical rule explaining how you should change

your existing hypothesis in the light of new evidence.In other words, it allows scientists to combine new data withtheir existing knowledge or expertise

A(Hypothesis)

B(Data)



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Example: Evaluating the Posterior Probabilityof thehypothesis that the Earth is a sphere...

10%

20%

30%

40%

50%

60%

70%

80%

90%

55% 60% 65% 70% 75% 80% 85% 90% 95%

Likelihoodofobservin

gX

given

A

Prior probability of A

80%-100%

60%-80%

40%-60%

20%-40%

0%-20%



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Example: Updating the Posteria Probabilitywithrepeated/improved observations

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1 2 3 4 5 6 7Posteriaprobability

thatourtheory(A)istrue

Experiment no

Bayes' Rule - Opdating of Theory via Observations

P(X|A) - L ikelihood of obs P(A|X) - probability that theiry is true

FALSIFICATION....!



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Hegels dialectical method or the principle ofdeduction by counter argument (towards the one and onlythruth.....)

Thesis Anti-Thesis

Syn-Thesis

Anti-Thesis

Syn-Thesis



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...sometimes it is a constructive approach:(union set = improvement/generalisation of theory = both-and)

EinsteinEinsteins general

relativity theory

Newtons

theorythe three

basiclaws

Space

Time

Newton



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...but it does not always work(as so many theories...)

The Earth is spherical....!The Earth is Flat....!

Disjunction set: Shift in paradigm = either or



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Finale:

Scienceis a process of learning to know thenature of everything in the material world, fromatoms to the most complex of living organisms

and inanimate objects... Scienceis not a Belief it is a methodology! No

more, no less...

Terima Kasih



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Break

Examples.....


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lecture 1 - the basis for the scientific method

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