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Philosophy and Nature of Science. Part 1. Philosophy Part 2. Philosophers. Basic Questions. How do we know? What is knowing? Can we know with certainty? Can we believe something with certainty? Are there facts? Is there truth?

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philosophy and nature of science

Philosophy and Nature of Science

Part 1. Philosophy

Part 2. Philosophers

basic questions

Basic Questions

How do we know?

What is knowing?

Can we know with certainty?

Can we believe something with certainty?

Are there facts?

Is there truth?

Can an hypothesis be verified or falsified?

what constitutes evidence

What Constitutes Evidence?

Is there a relationship between evidence and hypothesis?

What evidence does one select to establish an hypothesis?

how does one do science

How Does One Do SCIENCE?

Science does not adhere to the Baconian procedure of observation before hypothesis, hypothesis before testing.

It is more artistically driven. The scientist responds to an observed event by curiosity. The scientist follows up curiosity with persistence having no sure and fixed method to unravel the conundrum. Finally the researcher employs memory to relate one event to another and to avoid redundancy.

questions asked in the philosophy of science
Questions asked in the philosophy of science
  • Is science based on faith?
  • What is the scientific method?
  • How are new discoveries treated?
  • Is everything reducible to physics and mathematics?
  • Is everything reducible to a few rules?
science and faith

Science and Faith

Some Articles of Faith

Science is based on articles of faith:

The universe is consistent over space and time.

The universe is understandable.

We can understand the universe.

What’s valid here is valid there.

The universe is material and not spiritual

The universe is mathematical.

Experiment validates theory

what characterizes science
What Characterizes science?
  • A method for retaining reliable knowledge about the universe due to test and retest
  • Science is a testing community
  • Science seeks consistency not truth
  • Science tells the best minimal story about the universe. Pieces fit into a puzzle
  • Science does not ask why, but asks how, what, where, and when. Science seeks measurement
ideal scientific method
Ideal Scientific Method
  • Observation
  • Repetition
  • Induction(1)


  • Deduction or generalization

Consequence or prediction

  • Testing
  • Induction(2)
  • Induction (1) not successful
critique of the ideal scientific method
Critique of the Ideal scientific Method
  • What’s observed and studied depends on the currently accepted explanation
  • Explanation selects the observation

Explanation Influenced by:

Brain hardware

Gestalt formation

Optical illusions

Brain Software




Observation -----------------> Hypothesis

  • Induction goes from effect to cause.
  • Effect can possibly have many causes.
  • A cause may have a single effect.
  • Hypothesis is a kind of cause



critique of induction
Critique of Induction
  • There is no logical way of going from observation to hypothesis
  • Hypothesis is a simple guess
  • Frequently hypothesis precedes observation
hypothesis theory fact
Hypothesis, Theory, Fact
  • Hypothesis are Guesses not logically derivable from deduction or Induction
  • Theories are statement of Probability
  • Facts do not exist- nothing is 100% certain
verification falsification
Verification & Falsification
  • What is meant by explanation?
  • What is a fact?
  • When is a Fact verified?
  • How many observations needed?
deduction and induction
Deduction and Induction


Observation ------------> Hypothesis


Hypothesis ------------> Observation

  • If there is no cogent way of going from observation to hypothesis
  • Then there is no cogent way of deducing from hypothesis to observation
critique of deduction
Critique of Deduction
  • Modern Science does not seek causes but seeks relationship among variables
  • Independent variables are not causes and dependent variables are not effects
  • If one knows Y =g(x), can one predict (deduce) the future?
verification and falsification
Verification and Falsification
  • Replace Verification with Falsification
  • Verification and falsification are asymmetrical
  • Multiple verification does not establish a theory more than a single verification
  • A single falsification overturns a theory

It takes only one green swan overturns the theory that all swans are white. Observing one million white swans does no more to prove all swans are white than witnessing ten white swans.

  • It is nearly impossible to falsify an hypothesis.
  • Since a test depends on many factors it is difficult to determine whether the hypothesis failed or one of the other factors failed.
  • Some failures of dependent factors:

precision and accuracy of instrumentation, correct interpretation of data, flawless recording of data, improper experimental conditions

transition to immanuel kant

Transition to Immanuel Kant

Rationalism and Empiricism

historical overview
Historical Overview











  • Basic tenets of Empiricism
    • All knowledge comes from experience
    • The mind is a blank slate (tabula rasa)
    • The mind is passive, merely a receptor of sense impressions
  • Hume’s radicalizes these, ending in Skepticism
    • Unbridgeable gap between sense impressions and objects in the world
    • All we know are ‘sensations’ playing in our minds
    • The necessary ‘connectedness’ of experience is problematic Causality is merely superstition, born of habit
  • Basic tenets of Rationalism
    • Reason has access to reality as it really is
    • Reason can go beyond what is given to us in experience
    • Reason can then grasp things, not as they appear, but as they really are
  • The Leibniz-Wolffian School
    • Reason (without experience) can know about God, immortality of the soul, and human freedom
  • Reason has direct access to “meta-physical” knowledge
part 2
Part 2
  • John Locke
  • David Hume
  • Immanuel Kant
  • Thomas Bayes
  • Karl Popper
  • Thomas Kuhn
  • Imre Lakatos
  • B. 1632, son of a small property-owner and lawyer
  • Oxford, 1652-67
  • Studied church-state issues, chemistry and medicine, new mechanical philosophy
  • Involvement in politics through Lord Ashley, whom he treated for a liver abscess
  • Plotted to assassinate King Charles II and his Catholic brother, later James II
  • Exile in Holland, 1683-89
  • 1689: 3 major works published
major works and themes
Major works and themes:

A Letter Concerning Toleration (1689)

  • Argues for religious toleration;
  • Except for atheists, “who deny the Being of a God” and thus cannot be trusted to keep their promises (e.g. in contracts).


- Religious wars and persecution in England and on the Continent.

works cont
Works, cont.

Essay Concerning Human Understanding (1689)

  • Argues against innate ideas
  • For the acquisition of knowledge through the senses: “Intuitionism”
  • Anti-Cartesian (Descartes)
  • Re-opens debate about essentialism vs conventionalism with his views on identity, comparison, classification and natural kinds.
works cont30
Works, cont.

Two Treatises on Government (written 1679/80; published 1689/90)

  • First: Argues against traditional basis for political authority expressed in Filmer’s Patriarcha, divine right of kings;
  • Second: protection of private property, life and liberty = basis for civil government.
locke s basic epistemology
Locke’s Basic Epistemology
  • Human being = tabula rasa (blank slate)
  • receives sense-impressions
  • some of these transformed by Mind into Ideas
  • Ideas represented in language by words
  • However, no Ideas are innate
  • Mind operates (through gradual learning process) w/out reference to any received authority (of Church, State or others)
complex ideas
Complex Ideas
  • Sense-data of primary qualities (PQs) and secondary qualities (SQs), produce ideas in the mind:
  • Ideas are mental results of sense-data
  • -Sense-perceptions
  • -Bodily sensations
  • -Mental images
  • -Thoughts and concepts
primary pq and secondary qualities sq

Primary(PQ) and Secondary Qualities(SQ)

Distinction between perceived aspects of things. The primary qualities are intrinsic features of the thing itself (its size, shape, internal structure, mass, and momentum, for example), while the secondary qualities are merely its powers to produce sensations in us (its color, odor, sound, and taste, for example). This distinction was carefully drawn by Galileo, Descartes, Boyle, and Locke, whose statement of the distinction set the tone for future scientific inquiry. But Foucher, Bayle, and Berkeley argued that the distinction is groundless, so that all sensible qualities exist only in the mind of the perceiver.

attacks innatism descartes
Attacks Innatism (Descartes)

Locke’s objections to innate ideas (“II’s”)

  • Lack of universal assent: II’s not known to idiots, children, illiterates
  • Dependence on authority:
  • “…a Man is not permitted without Censure to follow his own Thoughts in the search of Truth, when they lead him…out of the common Road”.
  • Epistemological and political commitment to the individual (who is the foundation of Locke’s political liberalism).
david hume 1711 1776

Revised, 11/21/03

David Hume(1711-1776)

An Inquiry Concerning Human Understanding




1 sensation the origin of ideas
1. Sensation & the Origin of Ideas
  • The contents of the mind: (1) ideas & (2) impressions (sensations & feelings) -- Ideas (concepts, beliefs, memories, mental images, etc.) are faint & unclear; impressions are strong & vivid.
  • Ideas are derived from impressions: All ideas are copies of impressions.
  • The meaning of ideas depends on impressions
the empirical criterion of meaning

The empirical criterion of meaning

"From what impression is that alleged idea derived?"

No impression, no meaning?

No impression, no foundation in reality?

two kinds of ideas or judgments
Two kinds of ideas(or judgments)

"All the objects of human reason or inquiry may naturally be divided into two kinds: relations of ideas and matters of fact".

"Hume's Fork"


Judgments concerning relations of ideas


("Hume's Fork")

Judgments concerning matters of fact

judgments concerning relations of ideas
Judgments concerning relations of ideas
  • Intuitively or demonstrably certain
  • Discoverable by thought alone [a priori]
  • Cannot be denied without contradiction

*Hume's examples: Pythagorean Theorem


3 x 5 = 30  2


The Pythagorean Theorem

On a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides




32 + 42 = 52

(9 + 16 = 25)


judgments concerning matters of fact
Judgments concerning matters of fact
  • "Every judgment concerning matters of fact can be denied without contradiction" (e.g., "the sun will not rise tomorrow").
  • Neither intuitively nor demonstrably certain
  • Not discoverable by thought alone [a priori], but rather on the basis of sense experience [a posteriori]

More specifically,

all judgments concerning matters of fact are based on

All judgments concerning matters of fact are based on . . . .

the more fundamental] belief that there is "a tie or connection" between cause & effect.

and why do we believe that there is a tie or connection between cause effect
And why do we believe that there is a "tie or connection" between cause & effect?

Answer: The belief arises entirely from experience [a posteriori, not a priori], namely, the experience of finding that two events (cause & effect) are "constantly conjoined" with each other.

it is not logically necessary that a particular effect follows a particular cause

It is not logically necessary that a particular effect follows a particular cause;

it is just a fact of experience.

This view leads to Hume's discussion of . . . .

hume on induction
Hume on Induction
  • Induction is the process of drawing inferences from past experiences of cause & effect sequences to present or future events.
  • Hume's point is that an "effect" cannot be validly deduced from its "cause;"
  • the inference from "cause" to "effect" is based on past experiences of "constant conjunction," and these past experiences . . . .
accustom or habituate us

accustom or habituate us

to believe that one event is the cause of another, which we believe to be the effect of the prior event.

This is what leads us to believe that . . . .

the future will resemble the past

the future will resemble the past.

It is all a matter of CUSTOM or HABIT.

This is the foundation of . . . .

the idea that there is a necessary connection between cause effect
The Idea that there is a Necessary Connection between Cause & Effect

If this is a meaningful (& true?) idea, then (according to Hume) it must be derived from sense impressions.

What, then, is the sense impression from which this idea is derived?

There is no sense impression of causal power or necessary connection of cause & effect, but we do experience . . . .
  • (1) the spatial contiguity,
  • (2) the temporal succession, and
  • (3) the constant conjunction

of "cause" & "effect."

it is from this experience
It is from this experience,
  • especially the experience of constant conjunction,
  • that the idea of a necessary connection between "cause" & "effect" arises (or is inferred);
  • but the "inference" is simply a matter of "custom or habit."
    • This seems to mean that the "inference" here is psycho-logical rather than logical. Actually, there is no experience of the necessary connection between cause and effect. Thus, all factual judgments (which are based on the assumption that there is a necessary connection between cause and effect) are subject to doubt.
    • No necessity, no certainty.

Immanuel Kant

• 1724-1804

• Lutheran (Pietist) background

• “Second Copernican Revolution” in philosophy

• Spent all his life in Königsberg, a small German town on the Baltic Sea in East Prussia. (After World War II, Germany's border was pushed west, so Königsberg is now called Kaliningrad and is part of Russia.)

Groundwork of the Metaphysics of Morals


Immanuel Kant

• At the age of fifty-five, Kant had published much work on the natural sciences, taught at Königsberg University for over twenty years, and achieved a good reputation in German literary circles.

• During the last twenty-five years of his life, however, Kant's philosophical work placed him firmly in the company of such towering giants as Plato and Aristotle.

Groundwork of the Metaphysics of Morals


Immanuel Kant

• Kant's three major works are often considered to be the starting points for different branches of modern philosophy:

the Critique of Pure Reason (1781) for the philosophy of mind;

the Critique of Practical Reason (1788) for moral philosophy;

and the Critique of Judgment (1790) for aesthetics.

Groundwork of the Metaphysics of Morals


Immanuel Kant

• The Grounding for the Metaphysics of Morals was published in 1785, just before the Critique of Practical Reason.

• It is essentially a short introduction to the argument presented in the second Critique.

Groundwork of the Metaphysics of Morals


Kant’s Intellectual Climate

• Kant lived and wrote during the Enlightenment. This period produced the ideas about human rights and democracy that inspired the French and American revolutions. (Some other major figures of the Enlightenment were Locke, Hume, Rousseau and Leibniz.)

• The characteristic quality of the Enlightenment was an immense confidence in reason, i.e. humanity's ability to solve problems through logical analysis. The central metaphor of the Enlightenment was a notion of the light of reason dispelling the darkness of mythology and misunderstanding.

Groundwork of the Metaphysics of Morals


Kant’s Intellectual Climate

• Enlightenment thinkers like Kant felt that history had placed them in the unique position of being able to provide clear reasons and arguments for their beliefs.

• The ideas of earlier generations, they thought, had been determined by myths and traditions; their own ideas were based on reason.

Groundwork of the Metaphysics of Morals

(According to this way of thinking, the French monarchy's claims to power were based on tradition; reason prescribed a republican government like that created by the revolution.)



• Kant's philosophical goal was to use logical analysis to understand reason itself. Before we go about analyzing our world, Kant argued, we must understand the mental tools we will be using.

• In the Critique of Pure Reason, Kant set about developing a comprehensive picture of how our mind – our reason – receives and processes information.

Groundwork of the Metaphysics of Morals



• Kant later said that the great Scottish philosopher David Hume (1711-1776) had inspired him to undertake this project. Hume, Kant said, awoke him from an intellectual "slumber."

• The idea that so inspired Kant was Hume's analysis of cause-and-effect relationships.

Groundwork of the Metaphysics of Morals



According to Hume, when we talk about events in the world we say that one thing ‘causes’ another.

But nothing in our perceptions tells us that anything causes anything else. All we know from our perceptions is that certain events regularly occur immediately after certain other events.

‘Causation’ is just a concept that we employ to make sense of why certain events regularly follow certain other events.

Groundwork of the Metaphysics of Morals



• Kant took Hume's idea and went one step further. Causation, Kant argues, is not just an idea that we employ to make sense of our perceptions. It is a concept that we cannot help but employ. We don't sit around watching events and then develop an idea of causation on the basis of what we see. We automatically bring the concept to bear on the situation.

Groundwork of the Metaphysics of Morals



• Kant argued that causation and a number of other basic ideas (e.g., time and space) are hardwired, as it were, into our minds. Anytime we try to understand what we see, we cannot help but think in terms of causes and effects.

Groundwork of the Metaphysics of Morals



Kant's argument has huge implications. If our picture of the world is structuredby concepts that are hardwired into our minds, then we can't know anything about how the world ‘really’ is.

The world we know about is developed by combining sensory data (‘appearances’ or ‘phenomena,’ as Kant called them) with fundamental concepts of reason (‘causation,’ etc.).

We don't know anything about the ‘things-in- themselves’ from which sensory data emanates.

Groundwork of the Metaphysics of Morals



• This recognition that our understanding of the world may have as much to do with our minds as with the world has been called a “Copernican Revolution” in philosophy – a change in perspective as significant to philosophy as Copernicus’s recognition that the earth is not the center of the universe.

Groundwork of the Metaphysics of Morals



• Kant's insights posed a severe challenge to many earlier ideas.

Ex.: Before Kant many philosophers offered ‘proofs’ of the existence of God.

One argument made was that there must be a

"first cause" for the universe. Kant pointed out that the question of whether there "must" be a first cause for the universe is irrelevant, because it is really a question about how we understand the world, not a question about the world itself.

Groundwork of the Metaphysics of Morals



• Kant’s analysis similarly shifted the debate over free will and determinism. (Kant presents a version of this argument in Chapter 3 of the Groundwork.)

When we use reason to understand why we have made the choices we have, we can come up with a causal explanation. But this picture is not necessarily accurate. We don't know anything about how things "really" are; we are free to think that we can make free choices, because for all we know this might "really" be the case.

Groundwork of the Metaphysics of Morals



• In the Critique of Practical Reason and the Grounding for the Metaphysics of Morals, Kant applies this same technique –using reason to analyze itself – to determine what moral choices we should make.

• Just as we cannot rely on our picture of the world for knowledge about how the world "really" is, so also we cannot rely on expectations about events in the world in developing moral principles. Kant tries to develop a moral philosophy that depends only on the fundamental concepts of reason.

Groundwork of the Metaphysics of Morals


Kant’s Intellectual Climate: Criticisms

Some later thinkers have criticized Enlightenment philosophers like Kant for placing too much confidence in reason. Some have argued that rational analysis is not the best way to deal with moral questions.

Further, some have argued that Enlightenment thinkers were pompous to think that they could discover the timeless truths of reason; in fact, their ideas were determined by their culture just as all other people’s are.

Groundwork of the Metaphysics of Morals

karl popper
  • Popper replaces induction with falsification
  • Science is not distinguished from non-science on basis of methodology. No unique methodology specific to science
  • Science consists mostly of problem solving.
karl popper75
  • All observations are selective and theory laden
  • A demarcation between science and pseudo-science is established by falsification. A theory is scientific only if it is refutable by a conceivable event
  • Every genuine test of a scientific theory is based on an asymmetry between verification and falsification
sir karl popper 1902 1994
Sir KarlPopper (1902-1994)
  • Falsification is the idea that science advances by unjustified, exaggerated guesses followed by unstinting criticism.
  • Any "positive support" for theories is both unobtainable and superfluous; all we can and need do is create theories and eliminate error
  • Scientists never actually use induction. It is impossible to verify propositions by reference to experience
falsificationism 1
Falsificationism (1)

Scientific Method

  • Is there a scientific method?
  • What justifies scientific claims to knowledge?
  • Can we distinguish scientific method from non-scientific ways of thinking? (demarcation)
  • Does science progress?
falsificationism 178
Falsificationism (1)

Falsificationism ‘No criterion of truth’:

Two Arguments:

  • No Theory/observation distinction:
    • ‘Here is a glass of water’ is theory laden
    • In accepting the statement we must accept a significant amount of theory
    • We have only as much justification for accepting the observation statement as we do for the theory
falsificationism 179
Falsificationism (1)

Falsificationism ‘No criterion of truth’:

Two Arguments:

  • No Theory/observation distinction:

Upshot: we cannot use observation to establish the truth of a theory

How can we establish the truth of scientific theories?

We can’t!

falsificationism 180


Falsificationism (1)

Confirmation and Pseudoscience

Good scientific practice:

E.g. Einstein’s general relativity

Conjecture: mass of the sun bends the path of light

Apparent location

Actual location

falsificationism 181
Falsificationism (1)

Confirmation and Pseudoscience

Good scientific practice:

E.g. Einstein’s general relativity

Conjecture: mass of the sun bends the path of light

  • If the apparent location of the observed star doesn’t shift, the theory is wrong.
  • It will have been refuted.
  • The mark of a scientific theory is whether it can be falsified by observation
falsificationism 182
Falsificationism (1)

Conjecture and Refutation:

“Falsificationists… prefer an attempt to solve an interesting problem by a bold conjecture, even (and especially) if it soon turns out to be false, to any recital of a sequence of irrelevant truisms” (CR: 231)

This gives us:

(i) a glimpse of scientific method

(ii) a demarcation criterion for science

falsificationism 183
Falsificationism (1)

Scientific method:

Scientific theories have deductive consequences

  • They can be falsified but not confirmed.
  • The objective of scientific theorizing is to put forward (bold) hypotheses and then test them in order to falsify them
  • Theories are falsified by basicstatements

(what is a basic statement?)

falsificationism 184
Falsificationism (1)


  • Scientific theories are those that can be falsified by basic statements.
  • Good scientific theories do not make themselves immune from falsification by use of ad hoc hypotheses
falsificationism 185
Falsificationism (1)

Progress of Science:

  • Science progresses by eliminating theories that have been falsified?
  • But does it progress?
  • A scientific theory cannot be shown to be true. But some scientific theories do have varying degrees of success. They resist falsification.
falsificationism 186
Falsificationism (1)

“We must not look upon science as a body of ‘knowledge’, but rather as a system of hypotheses which in principle cannot be justified, but with which we work as long as they stand up to tests, and of which we are never justified in saying that we know that they are ‘true’, or ‘more or less certain’ or even ‘probable’

kuhn 1
Kuhn (1)

Thomas Kuhn


The Copernican Revolution (1957)

The Structure of Scientific Revolutions (1962)

  • History of science not compatible with rationalist view
  • Progress of science not cumulative, driven by the application of a method
kuhn 188
Kuhn (1)

Thomas Kuhn


The Copernican Revolution (1957)

The Structure of Scientific Revolutions (1962)

  • No obvious science/non-science demarcation
  • No context of discovery/context of justification distinction
kuhn 189
Kuhn (1)

Kuhn’s History of Science

Two projects:

  • Descriptive — what is the structure of scientific history?

Normal science Scientific revolution

  • Explanatory — why does the history of science have this structure?


kuhn 190
Kuhn (1)

1. Kuhn’s History of Science

Descriptive Project:

Immature Science


Normal Science



paradigm diagram
Paradigm Diagram

old paradigm unexplained observations competing new



puzzle solving

one dominant paradigm

Mopping up operation

unsolved puzzles ignored

unexplained observations

unexplained observations and alternative interpretation ignored until enough accumulates to overturn current paradigm

kuhn 192
Kuhn (1)

1. Kuhn’s History of Science

Immature Science:

No prevailing school of thought

Various disparate theories


kuhn 193
Kuhn (1)

1. Kuhn’s History of Science

Normal Science:

  • Stability
  • Determination of significant facts
  • Matching facts with theories
  • Articulation of theories (refinement and extension)

“puzzle -solving” neither tests nor confirms its theories

kuhn 194
Kuhn (1)

1. Kuhn’s History of Science

Normal Science:

  • Driven by a paradigm (more later):
  • Commonly held set of beliefs, procedures, techniques
  • Agreement upon questions of import
  • Agreement on what counts as a solution
  • Agreement upon standards of evaluation
kuhn 195
Kuhn (1)

1. Kuhn’s History of Science


Not all expectations are borne out

  • Some anomalies lead to further discoveries (e.g. orbit of Uranus)
  • Some simply ignored
  • Troublesome anomalies

Challenge key theoretical concepts

Resist solutions

Inhibit application of theory

kuhn 196
Kuhn (1)

1. Kuhn’s History of Science


  • Weight of accumulated anomalies
  • No agreement on how anomalies are to be dealt with
  • Doubts arise
kuhn 197
Kuhn (1)

1. Kuhn’s History of Science


A new paradigm emerges

Old Theory: well established, many followers, politically powerful, well understood, many anomalies

New Theory: few followers, untested, new concepts/techniques, accounts for anomalies, asks new questions

kuhn 198
Kuhn (1)

1. Kuhn’s History of Science


A new paradigm emerges

Are old and new theories compared by some rational procedure?

“A new scientific theory does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it” (Planck)

kuhn 199
Kuhn (1)

Scientific Revolutions

The Ptolemaic model

The earth is at the centre of the planetary system


How to explain the retrograde motion of planets

kuhn 1100
Kuhn (1)

Scientific Revolutions

The Ptolemaic model

The earth is at the centre of the planetary system


How to explain the retrograde motion of planets





kuhn 1101
Kuhn (1)

Scientific Revolutions

The Ptolemaic model

The earth is at the centre of the planetary system

kuhn 1102
Kuhn (1)

Scientific Revolutions

The Ptolemaic Model:


  • Complexity: epicycle upon epicycle
  • The accumulation of anomalies
  • No clear way forward
kuhn 1103
Kuhn (1)

Scientific Revolutions

The Copernican model

The sun is at the centre of the planetary system


How to explain the retrograde motion of planets

kuhn 1104
Kuhn (1)

Scientific Revolutions

The Copernican model

The sun is at the centre of the solar system

kuhn 1105
Kuhn (1)

Scientific Revolutions

The Copernican Revolution was not the consequence of an old theory with less ‘empirical content’ being replaced by a new theory with more

  • No appeal to reason alone
  • ‘propaganda’

To discover how scientific revolutions are effected, we shall therefore have to examine … the techniques of persuasive argumentation within the quite special groups that constitute the community of scientists (SSR: 94)

kuhn 1106
Kuhn (1)

2. Explanatory Project

Two Questions:

  • If this is the course of the history of science, why?
  • Why aren’t competing theories/traditions measured against each other by some rational procedure?
kuhn 1107
Kuhn (1)

2. Explanatory Project


Disciplinary Matrix:

(i) Symbolic generalisations

(ii) Metaphysical commitments

(iii) Scientific values

(iv) Heuristic models

(v) Exemplars

kuhn 1108
Kuhn (1)
  • Explanatory Project

Why is normal science stable?

It is conducted wholly within the terms of a disciplinary matrix:





standards of evaluation

All are generated by the disciplinary matrix

kuhn 1109
Kuhn (1)
  • Explanatory Project

Why is theory change revolutionary?

Theory change is brought about by a ‘gestalt switch’ a complete change of world view

There is no neutral point from which one can assess theories from two paradigms simultaneously

thomas kuhn 1922 1996
Thomas Kuhn (1922-1996)
  • All research presupposes a world-view,a collection of fundamental objects, natural laws, definitions, and above all a definition of what research is.
  • Kuhn called a world-view, paradigms
  • Mature science have established paradigms
  • Example of mature sciences are chemistry, physics, geology; whereas, economics and psychology are

immature sciences.

  • Thomas Kuhn popularized the term in his book The Structure of Scientific Revolutions (1996) by using it to describe how science works. According to Kuhn, scientific explanations of the world are controlled by a paradigm, some model of how the world is expected to work and into which actual observations are fitted, even if the fit is not very exact. As inexact fits accumulate, it becomes more apparent that the dominant paradigm is inadequate as a model of reality. When enough contradictions exist, a paradigm revolution occurs and a new paradigm is adopted.
  • The word paradigm comes from the Greek paradeiknunai and means "to compare." In science and philosophy it has the same basic meaning as in common usage: a model or instance used as a basis or example for further work.
need for paradigms
Need for Paradigms
  • Research requires paradigms
  • Paradigms are models of the way the world works
  • Without paradigms research is a random collection of observations lacking unification of structure into a whole.
  • Without paradigms, it is not possible to decide which are and which are not important observations
dominant paradigms
Dominant Paradigms

As a field matures, one paradigm becomes the dominant one. Once paradigms is established research progresses quickly

paradigm guides direction of research
Paradigm guides direction of Research

It becomes clear with aid of paradigm which research areas are fruitful. These areas are ones not totally explained

Paradigms give concepts and laws to build on.

paradigm shift
Paradigm Shift

Paradigm shift occurs when old paradigm shown inadequate

What is defined as research is reevaluated

Concepts turn upside down. Earlier research is


real research
Real research
  • Real Research occurs during a paradigm shift
  • Once a paradigm dominates, research becomes puzzle solving
  • Puzzle solving is not research due to answers known beforehand
example of puzzle solving
Example of Puzzle Solving

After Newton explained solar system, later scientists using Newton’s theory predicted

The presence of the then unknown planets

Neptune, Uranus, and Pluto

what new paradigms do
What New Paradigms Do
  • Discovery of new paradigm results in new questions being asked and old questions abandoned
  • Newton saw gravitation as a property of matter. Earlier theories tried to find a mechanical explanation as whirlpools in space or angels.
paradigms are incommensurable
Paradigms are Incommensurable
  • Paradigms have different world view. It is difficult to compare them
  • Consequently, science defines truth relative to a paradigm and not absolutely. Truth is a story
  • Science is a conformist society which present only the currently accepted theory

Consequently science defines reality relative to the accepted paradigm

  • Students are educated into the accepted paradigm and to ignore alternative paradigms
  • The society of science determines what scientists observe
imre lakatos 1922 1974
Imre Lakatos(1922 - 1974)`
  • All scientific theories are equally un-provable
  • Falsification doesn’t work due to rescue hypotheses
  • the "basic unit" of scientific development is not the scientific theory, such that science progresses when one theory proves to be more successful than another.
imre lakatos
Imre Lakatos

the "basic unit" is actually the research program. Science progresses when one research program becomes more productive and more useful than other and, hence, receives a greater share of social resources through funding and younger scientists looking to join. A research program is characterized by a particular set of "hard core" fundamental ideas and is deemed successful so long as it contents continue to increase.

imre lakatos123
Imre Lakatos
  • In reality scientists do not abandon theories. They invent rescue hypotheses or ignore anomalies or refutations
  • Popperian crucial experiments and Kuhnian revolutions turn out to be myths. What happens is progressive research replaces degenerating ones.
  • Progressive scientific programs predict and produce dramatic, unexpected observations and results


Science progresses toward its goal of increasing verisimilitude by advancing bold conjectures and then attempting to refute these by observations

  • Theories cannot be verified by observation


—no theory/observation distinction

  • Theories are falsified by basic statements
  • We choose between theories on grounds of corroboration (mark of verisimilitude)

Problems for Falsificationism (recap)


Some legitimate features of scientific enterprise are not falsifiable:

  • Probabilistic Statements
  • Existential Statements
  • Metaphysical Commitments
falsificationism finale
Falsificationism (finale)

Problems for Falsificationism

3. Basic Statements:

Theories are falsified by basic statements.

What warrants our acceptance of basic statements?

(i) Observation?: No. Basic statements are theory laden. Accepting them requires accepting theory

(ii) Decision/convention: not grounded in a rational procedure

falsificationism finale127
Falsificationism (finale)

‘Whiff of Inductivism’

A Dilemma for Popper:

  • Give up on induction

—No rational criterion for choosing between competing theories

—No rational grounds for continuing to use successful theories

  • Give up the distinctive features of falsificationism
falsificationism finale128
Falsificationism (finale)

Problems for Falsificationism

3. Basic Statements:

Theories are falsified by basic statements.

What warrants our acceptance of basic statements?

(i) Observation?: No. Basic statements are theory laden. Accepting them requires accepting theory

(ii) Decision/convention: not grounded in a rational procedure

scientific research programmes
Scientific Research Programmes

Revision versus Ad hoc Hypotheses

Two questions

In the light of anomalies:

  • What should one change?

Principle of least change

(ii) When should one abandon a theory(in favour of another)?

scientific research programmes130
Scientific Research Programmes

Scientific Research Programmes (SRP)

A theory is:

  • Rules of logic and mathematics
  • Metaphysical commitments
  • Statements of laws
  • Assumptions about initial conditions

A SRP is a lineage of theories. SRP evolve over time

Rules according to which SRP’s evolve over time.

scientific research programmes131
Scientific Research Programmes

Scientific Research Programmes (SRP)

Parts of a SRP:

Hard Core:

Theoretical assertions

Metaphysical commitments


Auxiliary Belt:

Initial conditions


Ad hoc hypotheses


scientific research programmes132
Scientific Research Programmes

Scientific Research Programmes (SRP)

Parts of a SRP:

e.g. Celestial Mechanics

Hard Core:

Laws of Motion

Universal Gravitation

Space and time


Auxiliary Belt:

Number of planets

Masses of planets