History and Philosophy of Science-B.Ed/M.Ed notes
Prepared by
Sabarish P
(MSc Physics, MEd, NET)
Contact: pklsabarish@gmail.com
The
primitive man picked up a stone and threw it against a wild animal to
protect himself. This process developed into the development of
tools and weapons. Almost every one of the early mechanical
achievements of man, even weaving and tailoring, had already been
mastered and excelled by specialised species of animals, birds or
even insects. But the use of fire was an art and technique only to
be mastered by man.
Primitive
man used fire to warm his body on cold nights. Later he learned to
heat water in leather buckets by dropping hot stones in to it. Later
he found that with a mud coating he could easily place the leather
bucket on the fire. And still later he found that the very leather
bucket could be dispensed with. This was the beginning of pottery.
Later wheeled vehicles, sail boat, emergence of civilizations……..
Such
a treatment in the Science classes may invoke ridicule on the part of
science students and helplessness on the part of professors of
Science. Students may enquire the relevance of studying the history
when the latest and most scientific inventions make the past outdated
and irrelevant. A study of the past is interesting in itself. But
an understanding of the past involves its critical analysis also.
Then it yields useful guidelines for the present and future
endeavours. (Remember the review of related literature in a PhD
work) It is not mere recounting of discoveries and inventions or a
chronology of Scientists and their achievements.
Science
is a process as well as product. A scientist (one who is earnest in
the pursuit of science) should acknowledge this. Rewards are due to
any person who is earnest in the process of science. The process is
rather more important than the product. There is a good illustration
for this fact in the history of Physics. JJ Thomson (Senior) and his
son George Thomson received Nobel prizes in 1906 and 1937
respectively for proving two opposite views on the same subject. The
former proved that electrons were particles and the later proved that
they were like waves.
Searching
the history tells us how those ideas germinated, grew, flowered and
sometimes wilted. And those who argue that we need to look only at
the latest scientific information and need not worry about the
earlier theories are treating science as a product.
Let
us examine critically the development of Heliocentric theory to know
how science emerged, withstanding tough times, sometimes breaking
barriers and sometimes hibernating for thousands of years.
Near-to-logic explanations started with Claudius Ptolemy (AD 85-165).
He was a genius in Mathematics who gave the table of sine values,
gave the correct value of π as 3.14167. He had identified the
positions of 1022 stars. He arranged the solar system with the earth
at the centre and Moon, Mercury, Venus, Sun, Mars, Jupiter and Saturn
revolving around it; in that order. Only the moon would move in a
simple circle; all the others needed complicated systems of epicycles
superimposed on their main orbital cycles. But the wonder was that
Ptolemy’s scheme was of course wildly erroneous; yet at the time
when it was propounded, it may have been more useful than truth! For
what could be more satisfying than the thought that our habitat, this
earth, was the centre of the Universe and what could be more natural
than that all the heavenly bodies were paying homage to it by
revolving around it in circles, which after all where the most
perfect and therefore divine of curves?
With
these comforting and pleasant dreams the science of astronomy went to
sleep for a thousand and five hundred years.
Copernicus
(1473-1543) was by profession a physician. His idea was that the
universe could be vastly simplified if the Sun rather than the earth
were taken as the centre. His new system placed the Sun at the
centre of the Universe and ascribed three motions to the earth: a
daily spin on its axis, an annual orbit around the Sun and a gyration
on the earth’s axis of spin to account for the precession of
equinoxes.
He
wrote: “To be sure, the majority of the writers agree that earth is
at rest, so that they consider it unbelievable and even ridiculous to
suppose the contrary…….”
The
greatness of Copernicus was that, he for the first time demonstrated
and proved that a heliocentric arrangement could produce all the
apparent movements in the celestial canopy, which we witness from the
earth. But Copernicus also used epicircles and eccentric circles to
describe planetary orbits.
Strangely
enough the book did not have much of an impact. (It did not even
have the distinction of being banned by the church.)
Its
revolutionary central concept was lost in a maze of mathematical
jugglery.
In
spite of a new model, Copernicus could not improve upon the accuracy
of the Ptolemic system.
Objections
against the heliocentric (which are apparently rational) where not
addressed.
Would
not all loose objects be flung into space by this whirling sphere?
If
the earth moves through space around the sun, why do the stars not
change position relative to one another (stellar parallax)?
Tyco
Brahe (1546-1601)
He
built an observatory in the island of Hveen. He use the ever
accurate set of instruments, made remarkably accurate observations
every night for 20 years.
He
opposed the heliocentric theory of Copernicus. (He thought it
contrary to sound Physics as well as clear world of scripture). He
was willing to strike a compromise between the Ptolemic system and
Copernican theories, by letting the planets revolve around the Sun
but insisting that the entire heavens revolve around the earth daily.
His main purpose in amassing such accurate observations was to
adduce sufficient proof for this pet theory of his.
But
it is one of the remarkable ironies of the History that the very same
data was used by his assistant and successor Johann Kepler, to banish
geocentrism once and for all from astronomic circles and to enthrone
the very Copernican System which the master so vehemently distrusted.
Kepler
put his laws as 1. the paths of the planets around the sun are
ellipses. 2. The planets travel more fast when they are near the sun
than when they are away from it. (Planets move so that their radius
vectors sweep out equal areas in equal time intervals.) 3. the ratio
between the square of the time required by the planet to make a
complete revolution around the Sun and the cube of the average
distance from the sun is constant for all planets.
Giordano
Bruno (1547-1600)
He
was a man who contributed more for the development of science by his
death, than he probably would have ever achieved by living a long
life. He taught in a few French universities and wrote a book “on
the infinite Universe and the Worlds”. If Copernicus had displace
the earth from the centre of the universe, Bruno displaced the sun
also from such an exalted position. In fact he said that there was
no centre, for “as the universe is infinite, no body can properly
be said to be in the centre of the universe or at the frontier
thereof.” Man’s home in space occupied no preferential
position.
The
doctrine so Bruno struck at the very vitals of the orthodox beliefs;
the idea of the infinite world, the identity of the creator and His
creation, the insignificance and non uniqueness of man and his
habitat, the earth – all this was anathema to the Church. In 1593,
he was captured, tried in courts and sentenced to death. Bruno is
said to have commented to his judge; “ perhaps you who condemn me
are in greater fear than I who am condemned.”
This
entire history illustrate that Science is the process of seeking
truth. Some people assume that scientists have generated a body of
knowledge that is sure to be true for all times. No true scientist
(one who is in the earnest pursuit of science) should get ego
involved that they refuse to accept new evidence and new ideas.
Theories come and go, or at least are modified through time, as old
ideas are questioned and new evidences are discovered. In the words
of Karl Popper, “Science is a history of corrected mistakes”.
Albert Einstein remarked about himself, “That fellow Einstein…
every year retracts what he wrote the year before.”
But
one should not got to the other extreme view on science – that new
ideas and evidences constantly prove the earlier theories totally
wrong. In fact the heliocentric theory has changed from Copernicus.
Copernicus himself maintained that the orbits of the planets around
the sun were perfectly circular. Later after two centuries it was
apparent that the orbits are ellipses. In the 20th
century we have additionally fond that the exact shapes of ellipses
are not constant. (hence the Milankovitch cycles that may have
influenced the periodicity of glaciations). However we have not gone
back to the idea of an earth centered universe. Instead, we still
accept a heliocentric theory – accounted with the modifications
with regard to new data.
The
structure of science can be compared to the frame work of a building
under construction. A frame work of a building consists of
foundation, vertical pillars and horizontal beams. The foundation of
the frame work is comparable to the broad generalisations and
principles of science. The vertical pillars to the theories and
horizontal beams to the methods employed in science. The facts are
comparable to building materials ie., stone, bricks, concrete etc.
in this analogy of ‘house under construction’ vertical pillars
and horizontal beams shall get altered but the foundations are
strong.
One
may say that while the history of science deals with the history of
ideas the philosophy of science deals with the logic of ideas.
Science is not purely mechanical. The technical details an dobserved
data are carefully processed only by an analytical mind to extract
inferences. Logicla thinking and reaoning are essential in the
process of science. The thinking which the Scientists employ is no
different from the thought processes of a person of any other
discipline.
The
logical mind involved in the process of science raises certain
fundamental questions. What is science? How do we explore science?
What is the nature of truth? If science is objective, what is the
reality pertaining to that objectivity? Is there an objective
reality out there, independent of the observer?
‘Science
is a cumulative and endless series of empirical observations which
result in the formation of concepts and theories, with both concepts
and theories being subject to modification in the light of further
empirical observations. Science is both a body of knowledge and the
process of acquiring it.” –Frederick Fitzpatrick.
The
Aristotelians had believed that the shape of a body determined
whether it would sink or float in water. Galileo in a magnificently
simple experiment let a ball of wax sink into the bottom of a vessel
containing water and then increased its density of the liquid by
dissolving in it. When the density reached a critical value, the wax
ball rose to the surface.
The
best way to filter pseudoscience is Karl Popper’s falsifiability.
Popper claims that a scientific statement must be falsifiable. And a
valid statement must not yet have been proven false. There are
statements that cannot be proven to be true or false. For example if
a student says that in the magnet –solenoid experiment, the
electricity is produced by a genie, the statement is not scientific
because the statement cannot be proven true or false. But if the
student says that the solenoid acts as a voltage source by the mere
presence of a magnet, the statement can be tested with the help of a
galvanometer. The statement made was scientific but as soon as the
statement was tested wrong, it became invalid and hence not
scientific. Pseudoscience with very little evidence or on the basis
that it cannot be disproved claims to be scientific. For example
astrology, Feng shui, faith healing, hypnosis etc could not be tested
empirically. The argument that the effect of such have not been
disproved is no reason to believe it. Nevertheless in order to claim
the credibility of science it should prove itself by empirical tests.
Scientific
method is the procedure adopted by scientists in their investigation.
It is a systematic and orderly method of solving problems. The
steps of Scientific Method are
1.Sensing
the problem 2. Experimentation 3. collection of Data, Interpretation
of Data& Formu8lation of Hypothesis. 4. Establishment of the law
5. Centralisation of the law. 6. application of the law to new
situations 7. Predictability 8. Idealisation and Abstraction
.
The scientific method has both technical and logical elements. The
technical elements include observation, experiment and collection of
facts and data. The logical elements include inductive and deductive
thinking, analogy, analysis, synthesis, hypothesis formation etc.
Induction
may be defined as the operation of ddiscovering and proving general
propositions. It is the operation of mind by which we infer that
what we know to be true in a particular case or cases will be true in
allcases which resemble the former in cer6t5ain assignable respects.
It ias attributing truth to a general proposition when particular
cases are found to be true. Thus induction is aprocess of inference
which proceeds from the known to the unknown. In inductive reasoning
conclusions are reached by observing exaples and generalising from
the examples to the whole class. If we want to be perfect in
inductive inference, we must observe all instances of the
pehenomenon. Take an example:
From
the given instances,
Rabbit
No 1 has lungs
Rabbit
No 2 has lungs
Rabbit
No 3 has lungs
Rabbit
No ‘n’ has lungs
Inference
: Every rabbit has lungs.
In
this example to be absolutely sure that every rabbit had lungs the
researcher would have to have observations on all rabbits presently
alive as well as past and future rabbits. This is impossible.
Therefore we may rely upon imperfect induction based on incomplete
observation.. All inductive inferences are based on two laws
a.
the law of uniformity of nature. This means that a phenomenon that
takes place in certain circumstances will repeat itself whenever the
same circumstances occur. Nature is uniform in her behaviour.
b.
the law of causation.- Nothing takes place by sheer chance . Every
phenomenon has a cause or set of causes invariably connected to it.
Both
these laws have no proof. See the paradox that all scientific
inferences based on induction are based on philosophic laws with no
proof.
It
was the Greek philosopher Aristotle, who perfected the syllogistic
method of deductive reasoning (syllogism).
Deduction is the process
of reasoning that starts from an accepted generalisation and moves
towards a conclusion relating to any specific instance . To
legitimate syllogism, it is essential that there should be three and
no more than three propositions namely the major premise, minor
premise and the conclusion.
All
men are mortal | Major premise must be true
All
kings are men | Argument must be valid
All
kings are mortal | Inference follows naturally
One
of the major weakness of this method is that it can only deduce the
consequences of pre-existing knowledge. It does not probe beyond
that which is already known. Also deduction relies on verbal symbols
which can be quite ambiguous.
The
logical arguments determine the inferences. One has to be very
cautious while making interpretations.
Prepared by
Sabarish P
(MSc Physics, MEd, NET)
Contact: pklsabarish@gmail.com
