A Brief History of Science Part 12: The Rise and Fall of Positivism Soumitro Banerjee∗ The Advent of Positivism taste, smell, colour, and other aspects of an apple. But the apple is not a sum- We have seen earlier that post-Renaissance total of these sense experiences about it. development of science relied, to a large It is something else. This, he said, is extent, on empirical evidence in order to the ‘thing-in-itself’, and the aspects that dispel common misconceptions held since we have access to through our sense ex- antiquity. Francis Bacon advised scientists perience constitute, in his language, the to gather empirical data on a large scale. ‘thing-for-us’. He proposed this as a general In order to build a more complex body of concept: in everything that are subjects of knowledge from these direct observations, scientific investigation, there are ‘things-in- he recommended the use of inductive rea- themselves’ and ‘things-for-us’, the former soning (making generalizations based on being unknowable while we try to make individual instances). This approach saw sense of the world through the latter. quite a bit of success in the following century. Thus, the mood of the time was to We have seen that in the early part of the rely on empirical evidence in judging truth. 19th century there was great advancement This line of thinking was formalized by in different branches of science. With that, John Locke and David Hume in England, scientists faced the question of epistemol- by theorizing that all knowledge derives ogy: how do we come to know? What is the from sense experience. This point of view, correct way of knowing, or of investigating called empiricism, says that all concepts phenomena? At that time a viewpoint are about or applicable to things that can developed in continuation of the empiricist be experienced. All rationally acceptable tradition that was to exert enormous in- beliefs or propositions are justifiable or fluence on the scientific community in the knowable only through experience, also latter part of the 19th century. It was called called a posteriori knowledge. positivism. But what is amenable to sense experi- The initial proponent of positivism was ence? In Germany, Immanuel Kant (1724- the French philosopher and social scientist 1804) considered this question. His opinion Auguste Comte (1798-1857) who described was that corporeally existing things, by his ideas in his books ‘The Course in themselves, are not amenable to sense Positive Philosophy’ and ‘A General View of experience; only parts or aspects of it Positivism’. The term ‘positivism’, coined are. For example, we can experience the by Comte, derives from the emphasis on the positive sciences—that is, on tested ∗Dr. Banerjee is a Professor at the Indian Institute of Science Education & Research, and General Secre- and systematized experience rather than tary of Breakthrough Science Society . on undisciplined metaphysical speculation. 24 Breakthrough, Vol.18, No. 3, March 2016 Series Article that we experience. The purpose of science is simply to stick to what we can observe and measure. Knowledge of anything be- yond that, a positivist would hold, is impos- sible. Kant had divided the physical world into things-in-themselves and things-for- us, but believed in existence of the things- in-themselves. Mach went a step further and renounced even formal recognition of real material objects. According to Mach, taking any step beyond what is given by sensory data would tantamount to meta- August Comte (1798-1857) physical speculation. “The materialists, we are told, recognise something unthinkable and unknowable—‘things-in-themselves’— According to him, techniques for investigat- matter ‘outside of experience’ and outside ing phenomena should be based on gather- of our knowledge. They lapse into genuine ing observable, empirical, and measurable mysticism by admitting the existence of evidence, subject to specific principles of something beyond, something transcending reasoning. In the study of social sciences, the bounds of experience and knowledge.” he stressed the adoption of a ‘value-free’ or objective approach to the study of humanity The essence of positivism is to say that shares much in common with meth- that our knowledge of the world, which ods employed in the natural sciences, as starts from our sensations and sense- contrasted with speculation of how things impressions, can never extend to anything should or ought to be. beyond those sense-impressions, and that In the later part of the 19th century, the job of science is simply to correlate the doctrine of positivism was further de- observational data. The famous physicist veloped by Richard Avenarius (1843-1896) Arthur Eddington said that the data of in Switzerland, and especially by the fa- physics consisted in “pointer-readings and mous scientist Ernst Mach (1838-1916) in similar indications”; the physicist could Austria. Their viewpoint is also known as never say what lay behind those observa- empirio-criticism. For them, the answer tions; all he could do, or needed to do, was to the question “How do we know?” was: to state their correlations. The real world we know with the help of our sense per- could never be known to science. The pos- ceptions. Our knowledge about anything itivists opined that science should concern is nothing but a combination of sensations itself only with the ‘observables,’ for, in their received from that thing. The nerves carry opinion, what cannot be observed is not these sensations to the brain, and the brain real. forms perception about that object using As a result, positivists could not accept these signals. That is why, they said, the idea of causality. According to pos- sense experience is the only reliable source itivists, causality is nothing but a useful material for forming knowledge. word to use when correlating observations. They insisted on a strict adherence to But since all we can observe are the re- empirical data. According to them, the goal peated occurrence of events in a definite of knowledge is to describe the phenomena sequence (for example, cloud and rain), Breakthrough, Vol.18, No. 3, March 2016 25 Series Article properties of matter and the interactions between its different forms. The sharp line of difference between the positivists and materialists was that the first group refused to treat anything as real unless it is observ- able, while the second group argued that since matter exists independently of our consciousness, the reality of any concept does not depend on our ability to observe it. The way to reach the underlying reality of phenomena is through theory-building, and by testing the theories objectively. The Development of Science, 1870-1900 Ernst Mach (1838-1916) What was the intellectual climate in the later part of the 19th century? Idealism was science can only document the sequential still very strongly entrenched in common occurrence of events and cannot infer the peoples’ minds. Materialism had overcome existence of any real, objective causal con- the shortcomings of mechanical material- nection. ism and metaphysics, and was spreading On the face of it, the strict adherence among the rationally minded people and to empirical data obtained from sense per- among the scientists. But at the same time ceptions (enhanced with the aid of instru- the positivist philosophy emerged, received ments) seems to be a correct scientific wide publicity, and was gaining prominence standpoint. After all, this can be used as the guiding principle of science. to dispel many unscientific beliefs. To The materialists’ emphasis on objectivity the question “do ghosts exist?”, a scientist helped dispel many unfounded beliefs. The would say “no, because we do not perceive positivist approach gave impetus to exper- a ghost through our sense perception.” imental research and data collection. This That is why, most scientists in the later resulted in many important discoveries and part of the 19th century were swayed by technological inventions in the period from the positivist argument, and this approach 1870 to 1900. Here we list some of the became the de-facto ‘scientific method’. important advancements that occurred in Even though this line of thinking sounds this period. materialistic, in actuality it stands in sharp There was a speculative idea prevalent contrast to materialism. Materialists hold at that time, that the development of an that the universe is composed of matter, individual embryo repeated the same evo- the material world exists independently of lutionary stages of its ancestors. Wilhelm our consciousness, and there is nothing His (1831-1904) rejected this idea and supra-matter in this material world. The sought to discover the physical and chemi- multitude of phenomena which science in- cal causes for embryonic development. His vestigates is nothing but different forms new experimental approach gained many of matter in motion. That is why they followers, who studied the internal re- hold that all truths are to be found in the sponses of an egg to an altered physical 26 Breakthrough, Vol.18, No. 3, March 2016 Series Article environment. Thus, over the period 1875- i.e., the relative velocities, should be differ- 1900, embryology became an experimental ent. In 1887 the American scientists Albert science. Michelson and Edward Morley tried to de- It was a prevalent belief at that time that tect the relative velocity of light using the epidemic diseases were caused by some- motion of the Earth in its orbit employing thing called miasma, a noxious form of ‘bad a very precise spectrometer. They found air’ emanating from rotting organic matter. that the velocity of light through vacuum Louis Pasteur (1822-1895) experimentally is the same irrespective of the motion of showed that this belief was false, and the observer. This result also remained a that most infectious diseases are carried mystery for a long time.