History and Philosophy of Science-B.Ed/M.Ed notes
Prepared by
Sabarish P
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Students may enquire the relevance of studying the history when the latest and most scientific inventions make the past outdated and irrelevant.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
