A
Conversation with Roddam Narasimha:
“For 1400 years India and China led
the
world in science and technology”
Prof
Roddam Narasimha,
FRS, is a distinguished aerospace scientist, and among the first few Indian
engineers to be elected to several leading international academies like the
Royal Society, the US National Academies of Sciences and Engineering and the
American Academy of Arts and Sciences. He has contributed enormously to the
development of aeronautical and space sciences in India. He is presently at the
Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore. One of his
current areas of research is the study of cloud evolution and dynamics, a
subject of great relevance to the Indian monsoons and global climate change. He
has written several papers and articles on how ancient Indians ‘thought’
science. These are excerpts of a conversation between Shivanand Kanavi
and Roddam Narasimha.
Published
in Ghadar Jari Hai, Vol 9 Issue 3
And in rediff.com
http://www.rediff.com/news/interview/why-and-how-did-science-in-india-stagnate/20150814.htm
SK: What
got you interested in Indian science and what is your approach?
It began
during my student days in the US, when I was working for a PhD in aeronautical
engineering at the Graduate Aeronautical Laboratories, California Institute of
Technology (Caltech) in the late 50s. At Caltech one had the opportunity to
make friends with students from all over the world – from Europe to Vietnam and
Burma, and to meet and get to know an equally diverse but distinguished
international faculty. (I worked with one of them, Prof. Hans W. Liepmann.)
There
were great cultural differences among both faculty and students, but as far as
intelligence was concerned I did not see any great differences. Intelligence
seemed fairly uniformly distributed across the world. So if intelligence was
not the problem why were so many countries in the world (including India in
particular) rather backward economically and technologically? After meeting
many distinguished American scientists, including some Nobel Prize winners, for
example, I saw that they had indeed made extraordinary contributions, and some
of them (like Richard Feynman) were one-in-a million kind of truly exceptional
people, but they did not seem superhuman. And the science I had learnt in
Bangalore, while not as advanced as in California, was not dissimilar in kind;
its heroes were the same, and had come almost entirely from what one may call
the Euro West.
So the
question arose: hadn’t there been any science or any scientific geniuses in
India, and if there had been what were they like?
I
started reading about ancient Indic science. This was not easy because not many
books were available on the subject then at Caltech, but I did come across a
few very interesting ones. The first was Al Biruni, (Persian
encyclopedic, 973-1052 CE, among many other books author of Taḥqīq mā li-l-hind min maqūlah maqbūlah fī
al-ʿaql aw mardhūlah: “Verifying All That the Indians Recount,
the Reasonable and the Unreasonable”--Ed), who
had come to India about a thousand years ago with Mohammed of Ghazni as a kind
of scholar-in-residence in his moving court. Several chapters of Al Biruni’s
book are on Indian astronomy, and they were fascinating to read. He complains
that the Hindus think there is no science like theirs, no art like theirs, no
religion like theirs and so on. He said, there were pearls in their science,
but they were mixed with dung (mostly puranic stories)!
He
comments that some Indians believe in the wildest superstitions: how could the
reasoning and logic of somebody like Aryabhata (476–550 CE) be reconciled with such superstitions? He is
especially harsh on Brahmagupta (598–670 CE), who compromised his science by upholding the
mythologists, e.g. Rahu-Ketu myth on eclipses.
However
another scholar in the same century, the Spanish-Arab Said al-Andalusi, (1029-1070
CE, mathematician, astronomer, wrote "history of science": Al‐tarif bi-tabaqat al-umam (Exposition of the
Generations of Nations) seems
to have found mostly pearls in Indic science: in his history of world science
he surveyed the contributions of several peoples – Greek, Egyptian, Arab, Hindu
(i.e. Indian) etc., but among them the Hindus were the premier nation. They
were intelligent, innovative and creative, and a nation favoured by God, he
said.
One must
remember that at that time the Arab world was a great centre of international
scholarship. I found later that the Arabs were usually generous in
acknowledging what they learnt from other civilizations (including the Indian
and the Greek). There was an internationally known Hall of Wisdom in Baghdad,
and the books of Aryabhata, Brahmagupta, Charaka and Susruta had
all been translated into Arabic, and some into Persian and Chinese.
It
looked as if India had been a major player in science at that time, raising the
question when and why things changed. So when I returned home from the US I
started trying to read Indic science in the original Sanskrit. It was not easy,
but slowly it got to be absorbing.
SK: Can
you give an example of Aryabhata’s thinking?
Aryabhata
was rational, and there is hardly anything that you can call superstitious in
his writing. He knew that a solar eclipse occurred when the moon’s shadow falls
on the earth, and a lunar eclipse when the moon enters the earth’s shadow. From
the shape of the shadow on the moon he inferred that the earth must be round.
This may now be common knowledge, but at that time it was heresy. He went on to
propose that night and day were caused by earth’s rotation around its axis.
SK: Does
he say whether the system was geocentric or heliocentric?
He does
not make an explicit statement about it because for him relative motion was
what mattered. Actually he used a version of what is today called the Galilean
principle of relativity, and gives the example of how, as a boat sails down the
river, the trees on land appear to move in the opposite direction to the
occupants of the boat. What is stationary and what is moving? To him it does
not make a difference (to the dynamics).
SK: Did
you study Sanskrit?
Sanskrit
was my second language at school but I did not learn enough, so at my father’s
prodding I attended early morning classes at a temple in Gandhi Bazar. At
college I continued my contacts with Sanskrit by attending the late Shri D V
Gundappa’s remarkably multi-lingual, multidisciplinary Sunday classes at the
Gokhale Institute of Public Affairs in Basavanagudi. I started picking it up
again towards the end of my stay in the US, and began a rather desultory
programme of reading books in the original when I came back.
It
slowly became clear to me that Aryabhata, Bhaskara (Known as
Bhaskarachrya or Bhaskara II, 1114–1185
CE, mathematician, astronomer ) were very smart people indeed, and would
be comparable to the best I had seen anywhere. At the same time their style of
reasoning, their philosophy, and the way they ‘thought’– all of these seemed
very different. Thus the question became: why and how was it that science in
India was so strong in what the West calls its Dark Ages, but had in more
recent times stagnated and lagged behind?
SK: Can
we go back to the dispute between Aryabhata and Brahmagupta?
Aryabhata
rejected the story of a daanava named Raahu swallowing the sun or
his tail Ketu
covering the moon during eclipses. Eclipses occurred due to shadows, he said,
and he did not see any shadow of a tail ! Brahmagupta, who came more than a
century later, was a great mathematician himself, but did not agree with
Aryabhata about rejecting the Rahu-Ketu myth and criticized him and his
followers scathingly.
However,
one of these, Varahamihira (505-587 CE), dismissed Brahmagupta’s
arguments as ‘absurdities’, as Brahmagupta’s predictions of eclipses were also
based on the shadow theory ! (This inconsistency in Brahmagupta was Al Biruni’s
main target.) One thing I learnt from all this was that the debate between
mythology and ‘rational’ science in India is at least as old as Aryabhata and
Brahmagupta, and to this day has not been resolved in Indian popular thinking
on science.
I think
there is a wonderful play waiting to be written, a play involving Aryabhata and
Brahmagupta, Plato, Newton, Ramanujan, Neelakantha and so on, arguing across
the ages !
In spite
of the dispute, Brahmagupta and Aryabhata continued to be treated with respect
by later Indic mathematicians like Bhaskara and Neelakantha. Unlike in
Europe Aryabhata did not suffer an inquisition or punishment.
I
remember wondering as a kid what the Ontikoppal panchanga (published in Mysore,
brought home every Ugadi by my father), meant when it claimed it was made
‘Aryabhatiyareetya’ (following Aryabhata’s text the Aryabhateeya), mentioned
‘drg.ganita’ (syllables that sounded strange and fascinating to my childish
ears), and so on. Clearly Aryabhata was the father of an Indic approach to
astronomy that remained foundational for nearly 1500 years.
SK: What
was drg.ganita?
It signified an important concept in the
Indian philosophy of astronomical science. The major objective was to achieve
agreement between drik (seeing, observation) and ganita (calculation).
In
today’s language drg.ganita's outlook was that the computed prediction must
agree with observation.
This may
not seem surprising, but Greek thinking needed a conceptual model (sometimes
very elaborate, with assumptions many of which we now know to have been wrong)
before one got down to calculations (which they had largely learnt from the
Babylonians). Of course they also wanted agreement between prediction and
observation. On the other hand according to Plato a smart ‘geometer’ should be
able to figure it all out by pure thinking.
Indic
philosophy emphasized calculation without insisting on the elaborate models of
the Greeks– a philosophy that I like to think of as ‘computational positivism’.
This philosophy served us well till about a century after Newton – Indian
ganita predictions were as good as or better than the best elsewhere.
However
in the 19th century the power of the Newtonian revolution coupled with the use
of algebra and computation changed the character of astronomy (and other
physical sciences). And progress in Europe was so rapid and spectacular that
the level of accuracy achieved there surpassed that of Indic methods by large
margins early in the 19th century.
SK: So
was all Indic science rational?
No, we
have already talked about Brahmagupta, for example. However, I gradually came
to the conclusion that classical Indic science was indeed generally rational,
but it was rationality of a different kind; and it did have conflicts with
mythology.
We must
however remember that, although Newton is generally seen as rational about
his science, he did not consider it as important as what he secretly wrote
about theology. Not many know or remember that. Around that time and later
in Europe the possible existence of great ancient civilizations in Asia and
Africa became a serious issue, as estimates of their age were approaching the
Biblical date of Creation.
If you
compared the views expressed in Europe during the so called Dark Ages there
(before the Renaissance), Indian science was perhaps more rational than
European science of the time.
Nobody
tried or convicted Aryabhata just because he said Rahu-Ketu is nonsense. At the
same time Brahmagupta’s criticism did not affect his reputation as a brilliant
scientist. Both of them, I believe, were computational positivists, so their
other views seem to have been seen as secondary, lost in the indifference of
traditional Indic tolerance of different views.
SK: So
how long did this classical science last, and when and why did it end?
Some
twenty years ago I came across Joseph Needham, a distinguished British
scientist who had studied Chinese science and technology in great depth and
also wrote a bit on the sides about Indic science. He concluded that as the
West got to know more about Eastern science, the question that demanded an answer
was why neither China nor India gave birth to modern science, despite the fact
that they were ahead of the West in science and technology for 1400 years (say
200 CE to 1600 CE).
Why was modern science born in Pisa and not in
Patna or Peking? – Needham asked.
It was
the first time that I had seen a distinguished western scholar acknowledge so
readily that India and China had earlier been ahead for 1400 years. This
question is not much discussed in India. Some Indians take the extreme view
that everything was known to our ancients, but some others go to the opposite
extreme and consider everything Indian was superstition and rubbish (an
imperial British view typified by Macaulay’s comment about how one shelf of
good European books was worth the whole literature of India and Arabia). It
slowly became clear to me that both sides were wrong: the history of science is
not linear – it is chequered.
The
European dark ages were anything but dark in India; our dark ages have been the
last several centuries.
A study
of European opinion in the 15th-16th century leads to the conclusion that
Europe was becoming aware at that time that the East had been ahead of them.
They had encountered the more advanced Arabs during the crusades, Indian numerals
and algebra in the 16th-17th century, Chinese technologies in between – and
they began to see advances in Asia which they did not know about.
If you
read Francis Bacon you will see that he recognized the power of new inventions
like the printing press, the nautical compass, and gun powder (all from China,
as we now know) – inventions that had changed the world more than any empire,
sect or star, he said); and then there was sugar, which came from India. He was
dazzled by them, just as I was dazzled by all the things that the West had done
when I first went to the US.
Bacon
blamed the Greeks for the sad state of European knowledge. He called them a set
of quacks and charlatans; his criticisms of Plato and Aristotle were scathing.
Europe had taken the wrong path, and had to change. It is almost like what some
Indians began to say in the 19th and 20th centuries as our classical
epistemology collapsed: ‘all that we have learnt is worthless’.
As one
begins to analyse classical Indic and European texts, it becomes clear that,
deep down, at a fundamental level, it is all really about how one acquires
reliable new knowledge, i.e. about epistemology.
In the
17th century Newton almost implemented what Bacon had said. What changed at
that time? The standard western answer is mathematicization of science, but
that characterization is misleading. It depends on what you mean by
mathematicization. Surely one cannot say that ancient Greeks and Indians were
not mathematical?
Actually
what happened in the 16th-17th century was that the meaning of mathematics
changed. Till then it was geometry and Euclid in Europe (borrowed back,
incidentally, from the Arabs and their Arabic translations from the Greek a few
centuries earlier).
After
the 16th century it began to include numbers and algebra, both of which had
come from India. Algebra or beeja-ganita had developed into a ‘new maths’, and
was transmitted to Europe through creative Arabs and Persians; and the
trajectory of that diffusion can now be traced fairly well.
The word
algebra started getting used in Europe in the 15th-16th centuries, and slowly
grew in usage, even as the use of the word geometry declined. Indeed the new
mathematics even affected geometry, leading to what we now call analytical
geometry.
Thus
what really happened in Europe then was the algebraization of mathematics and
(a little later) of the exact sciences like physics. As the renowned
mathematical physicist Hermann Weyl said, Europe moved away from Greek ideas to
follow a path that had originated in India, where the concept of number had
been considered logically prior to the concept of geometry. I believe this was
a strong factor in the revival of science in Europe.
Bacon’s
formula of knowledge = power (in contrast to the Indic equation knowledge =
salvation) translated to growing power over the East. The European languages
did not have a word for algebra at the time so they took over the Arabic word al
jabr, just as we too have taken over TV, radio, etc. from English.
Descartes
once referred to algebra as ‘barbarous’: it was clearly not a direct Greek or
European legacy. Francis Bacon realized that much new knowledge had come from
outside the European culture area – presumably the East.
SK: What
is the concept of beeja and ganita, which you have spoken of
recently as 'Indic concepts that changed the world'?
Ganita
is literally reckoning, counting and manipulating numbers; gan is ‘to
count’ in Sanskrit. In the west a mathematician was, and was called, a
‘geometer’ for long; and in India a mathematician was a gan aka, a
numerist.
India
was number-centric. Bhaskara said beeja-ganita (algebra) is avyakta-ganita,
i.e. ganita with unmanifest (i.e. unknown) quantities, which need to be found
out from the data available and so made to become vyakta, ‘known’. That
unknown, the hidden, is beeja. Thus computing with the unknown so that
it becomes known is beeja ganita, which went as algebra to Europe
through the Arabs (who made their own creative contributions).It appears as if
the modern scientific revolution in Europe was a response to the inventions,
both mathematical and technological, that went from the east through the Arabs.
These inventions dazzled the Europeans, just as their inventions in turn
dazzled us two or three hundred years later.
SK:
So what was the difference between Europe and India in the way science was
done?
Neelakantha, a 15th-16th century
mathematician-philosopher from Kerala, explicitly tells us how to do science. I
had been trying to infer from Aryabhata and Bhaskara what their attitude
towards science and mathematics might have been, and then I came to know about
the Kerala school and Neelakantha’s Jyotirmimamsa (which unfortunately
has not yet been translated into English).
He
actually talks about epistemology, i.e. the science of knowledge-making, and
describes what methods lead to the generation of valid, reliable and
belief-worthy knowledge. Neelakantha’s views throw light on where Indians and
westerners differed in their epistemology.
Indic
methodology was primarily based on observation, experience (pratyaksha,
anubhava) and inference , skill (anumana, yukti). The Greek
conception was based on deductive two-valued (i.e. yes or no type) Aristotelian
logic, often following from stated axioms considered ‘true’ or self-evident
(typified by Euclid).
In the
15th -16th century a fusion seems to have started taking place between the two
in Europe. Though Indians were in touch with the Greeks, at least since the
times of Alexander, they only borrowed some tools from them but did not accept
their philosophy or ideology.
After
having rubbished Greek philosophy, Francis Bacon went on to invent a kind of
hybrid that combined experience, observation (in particular through
experimentation) with inference of axioms. Axioms thus ceased to be
self-evident truths, and became instead tentative inferences.
This
method began to be used with Newton, and led to what has spectacularly become
the global enterprise of ‘modern’ science. In his great work Principia
Mathematica Philosphiae Naturalis (The Mathematical Principles of Natural
Philosophy) – perhaps the biggest ever game-changer in the world of science –
Newton starts like Euclid in the first book, stating and discussing three
‘axioms’ (i.e. his three laws of motion); the rest is full of theorems, lemmas,
QED etc.
In the
third book he changes gear, introduces numbers from observations, and
inferences from them in the light of the axioms and results of Books I and II.
Book III
(of Principia-Ed) seems to me, partly Indic in style, because of the use of
inference: QIE (~ ‘what may be inferred’) often replaces the Euclidean QED (~‘what
had to be demonstrated’).
Newton
presumably realized that the third book is not in the Greek spirit, so he
inserts a short prefatory note on ‘The Rules of Philosophical Reasoning’ before
embarking on Book III, where he justifies his new procedure. He sets out and
explains four (new) rules, which have very little to do with the Greeks. But
there are also curious commonalities between India and Europe.
Calculus
was thought to be a purely European invention (as we are taught at school even
now), associated with the names of Newton and Leibnitz, but it was not. Many
important parts of it, at least, were known in Indian gan ita centuries
earlier. This included infinite series, for example, of the Taylor-Mclaurin
type, second-order difference schemes, the idea of limits – and so on.
Correspondingly,
it cannot be said that Archimedes (or some other Greek) started science
(compare Bacon); nor did it all start in India, for some little science must
have been there even at very early times.
There
were different contributions from different cultures. Ideas did travel (both
ways), but not all of them were accepted along their way by local cultures. For
example Indians borrowed the idea of epicycles from the Greeks, but used it
very differently: the smaller circle moving along the circumference of the
bigger one could keep changing its diameter. This would have shocked the Greeks
because for them it would spoil the symmetry and beauty of a model based on
just circles. To the Indians, however, the resulting kinky ellipse-like curve
was computationally simpler and more efficient. It was the sort of thing that
Bhaskara said would bring aananda to the ganakas !
Indians
never really took to Euclid till it came out of Macaulay’s bookshelf into the
educational system he prescribed for India in the 19th century. In the Indic
Nyaya system of knowledge creation (although it makes no reference to the
Greeks), the method of hypothesis to conclusion based on (deductive) logic is
frowned upon, because the basis for taking the hypothesis as a given truth
could not be justified. You have to compare it with or base it on observation. This
is where Bacon made his leap, coupling hypothesis and inference.
Pratyaksha (observation, including
experiment) was the number one pramaana (i.e. source of valid knowledge)
in all schools of Indian philosophy; it was universally accepted. This must
have been one of the few things that all of them agreed on! The second was anumaana
(inference), accepted by every school except the Lokaayatas. As
Neelakantha says, knowledge arises pratyakshena anumaanena – from
observation and from inference.
SK:
What about the aagamic pramaana?
After
getting an interesting mathematical result, Neelakantha says
etatsarvamyukti-moolam, natuaagama-moolam: all of this [comes] from
intelligent reasoning, not from the aagamas. Such a statement could not
have been safely made in the Europe of his time (~ 1500 CE).
SK: Aagama
can also be taken as existing accumulated knowledge rather than scriptural, an
important if not decisive source of knowledge.
The aagamas
were indeed accepted as a third pramaana in some Indic philosophical systems.
What you mention is close to what the Saamkhya philosophers call aapta
vacana (the word of the trust-worthy), which they accept as the third
pramaana after pratyaksha and anumaana, but they make it clear that Vedic
knowledge is not privileged, because it is also essentially human in origin, so
potentially fallible like any human work. In Nireeshwara Saamkhya they
say there is no evidence (pramaana-abhaava) for God. Of course they
don’t say that there is no God, but only that there is no evidence for it.
Classical
Indic scientists rarely appealed to scriptural knowledge in their science;
however many of them, including Neelakantha, were also very accomplished Vedic
scholars. In general, the great scientists (e.g. Charaka, Bhaaskara) had
respect for Saamkhya thinking. How can you say all this was not rational?
The
history of ideas, it seems to me, is chequered, and that makes it fascinating –
more fascinating than that of kings and battles.
