I didn’t know Kenneth Wilson had died on June 15 until an obituary appeared in *Nature* on August 1. He was a Nobel Prize winning physicist and mathematician whose contribution to science was and is great. He gave scientists the tools to imagine the laws of physics at different scales — large and small — and to translate causes and effects from one scale into another. Without him, we’d struggle not only to solve physics problems at cosmological and nuclear distances at the same time but also to comprehend the universe from the dimensionless to the infinite.

Wilson won his Nobel Prize in physics in 1982 for his work with phase transitions — when substances go from solid to liquid or liquid to gas, etc. Specifically, he extended its study to include particle physics as well, and was able to derive precise results that agreed with experiment. At the heart of this approach lay inclusivity: to think that events not just at this scale but at extremely large and extremely small scales, too, were affecting the system. It was the same approach that has enabled many physicists and mathematicians take stock of infinity.

**The idea of infinity**

As physicist Leo Kadanoff’s obituary in *Nature* begins, “Before Kenneth Wilson’s work, calculations in particle physics were plagued by infinities.” Many great scientists had struggled to confine the ‘innumerable number’ into a form that would sit quietly within their theories and equations. They eventually resorting to an alternative called renormalisation. With this technique, scientists would form relationships between equations that worked at large scales and those that worked at small ones, and then solve the problem.

Even Dirac, renormalisation’s originator, called the technique “dirty”. And Wilson’s biggest contribution came when he reformulated renormalisation in the 1970s, and proved its newfound effectiveness using experiments in condensed matter physics. Like Wilson’s work, the idea was interdisciplinary. But how original was it?

**The incalculable number**

Kenneth Wilson did not come up with inclusivity. Yes, he found a way to use it in the problems that were prevalent in mid-20th century physics. But in the *Mahavaipulya Buddhavatamsaka Sutra*, an influential text of *Mahayana* Buddhism written in the third or fourth century AD, lies a treatment of very large numbers centered on the struggle to comprehend divinity. The largest titled meaningful number in this work appears to be the *bodhisattva*(10^37218383881977644441306597687849648128) and the largest titled number as such, the*jyotiba* (10^80000 infinities).

The *jyotiba* may not make much sense today, but it represents the early days of a centuries-old tradition that felt such numbers had to exist, a tradition that acknowledged and included the upper-limits of human comprehension while on its quest to deciphering the true nature of ‘god’.

The *Mahavaipulya Buddhavatamsaka Sutra* itself, also known as the *Avatamsaka Sutra*, also contains a description of an “incalculable” number divined to describe the innumerable names and forms of the principal deities Vishnu and Siva. By definition, it had to lie outside the bounds of human calculability. This number, known as the *asamkhyeya*, owes its value to one of three arrived at because of an ambiguity in the *sutra*. *Asamkhyeya* is defined as a particular power of a *laksha*, but there is no indication of how much a *laksha* is!

One translation, from Sanskrit to the Chinese by Shikshananda, says one *asamkhyeya* is equal to 10 to the power of 7.1-times 10-to-the-power-of-31. Another translation, to English by Thomas Cleary, says it is 10 to the power of 2.03-times 10-to-the-power-of-32. The third, by Buddhabhadra to the Chinese again, says it is 10 to the power of 5.07-times 10-to-the-power-of-31. If they have recognisable values, you ask, why the title “incalculable”?

**Lesser infinities**

For this, turn to the Jain text *Surya Prajnapati*, dated c. 400 BC, which records how people knew even at that time that some kinds of infinities are, somehow, larger than others (e.g., countable and uncountable infinities). In fact, this is an idea that Galileo more famously wrote of in 1638 in his *On two New Sciences*:

“*So far as I see we can only infer that the totality of all numbers is infinite, that the number of squares is infinite, and that the number of their roots is infinite; neither is the number of squares less than the totality of all numbers, nor the latter greater than the former; and finally the attributes *‘*equal,’ ‘greater,’ and ‘less,’ are not applicable to infinite, but only to finite, quantities.*”

Archimedes, whose *Syracusani Arenarius & Dimensio Circuli* predated the *Avatamsaka Sutra* by about 300-400 years, adopted a more rationalist approach that employed the myriad, or ten thousand, to derive higher multiples of itself, such as the myriad-myriad. However, he didn’t venture far: he stopped at 10^64 for lack of a name! The father of algebra (disputed), Diophantus of Alexandria, and the noted astronomer Apollonius of Perga, who lived around Archimedes’ time, also stopped themselves with powers of a myriad, venturing no further.

Unlike the efforts recorded in the *Avatamsaka Sutra*, however, Archimedes’ work was mathematical. He wasn’t looking for a greater meaning of anything. His questions were of numbers and their values, simply.

In comparison — and only in an effort to establish the origin of the idea of infinity — 10^64 is a number only two orders of magnitude higher than one that appears in Vedic literature, 10^62, dated 1000-1500 BC. In fact, in the *Isa Upanishad* of the *Yajurveda* (1000-600 BC: Mauryan times), a famous incancation first appears: “*purnam-adah purnnam-idam purnat purnam-udacyate purnashya purnamadaaya puram-eva-avashisyate*“. It translates: “From fullness comes fullness, and removing fullness from fullness, what remains is also fullness”.

If this isn’t infinity, what is?

**In search of meaning**

Importantly, the Indian “proclamation” of infinity was not mathematical in nature but — even if by being invoked as a representation of godliness — rooted in pagan realism. It existed together with a number system, one conceived to keep track of the sun and the moon, of the changing seasons, of the rise and fall of tides and the coming and going of droughts and floods. There is a calming universality to the idea — a calming *inclusivity*, rather — akin to what a particle physicists might call naturalness. Inifinity was a human attempt make a divine being all-inclusive. The infinity of modern mathematics, on the other hand, is contrarily so removed from the human condition, its nature seemingly alien.

Even though the number as such is not understood today as much as ignored for its recalcitrance, infinity has lost its nebulous character — as a cloud of ideas always on the verge of coalescing into comprehension — that for once was necessary to understand it. Infinity, rather infiniteness, is an entity that transcends the character typical of the inbetweens, the positive numbers and the rational numbers. If zero is nothingness, an absence, a void, then infinity, at the other end is… what? “Everythingness”? How does one get there?

(There is a related problem here in physics, similar to the paradox of Zeno’s arrow: if a point is defined as being dimensionless and a one-dimensional line as being a collection of points, how and when did dimension come into being? Incidentally, the earliest recorded incidence of infinities in Early Greek mathematics is attributed to Zeno.)

**The lemniscate**

As it so happened, the same people who first recorded the notion of infiniteness were also those who recorded the notion of a positional numbering system, i.e. the number line, which quickly consigned infinity to an extremum, out of sight, out of mind. In 1655, it suffered another blow to its inconfinable nature: John Wallis accorded it the symbol of a lemniscate, reducing its communication to an horizontal figure-of-eight rather than sustaining a tradition of recounting its character through words and sense-based descriptions. We were quick to understand that it saved time, but slow to care for what it chopped off in the process.

Of course, none of this has much to do with Wilson, who by his heyday must have been looking at a universe through a lens intricately carved out of quantum mechanics, particle physics and the like. What I wonder is why did an Indian scientific tradition that was conceived with the idea of infinity firmly lodged in its canons struggle to make the leap from theoretical to practical problem-solving? There are answers aplenty, of course: wars, empires, scientific and cultural revolutions, industrialisation, etc.

**Remembering too much**

Wilson’s demise was an opportunity for me to dig up the origins of infinity — and I wasn’t surprised that it was firmly rooted in the early days of Indian philosophy. The *Isa Upanishad* incancation was firmly implanted in my head while I was growing up: the Brahminical household remembers. I was also taught while growing up that by the seventh century AD, Indians knew that infinity and division-by-zero were equatable.

It’d be immensely difficult, if not altogether stupid, to attempt to replace modern mathematical tools with Vedic ones today. At this stage, modern tools save time — they do have the advantage of being necessitated by a system that it helped create. Instead, the Vedic philosophies must be preserved — not just the incantations but how they were conceived, what is their empirical basis, etc. Yes, the household remembers, but it remembers too specifically. What it preserves has only historical value.

The Indian introspective and dialectic tradition has not given us just liturgy but an insight into the modes of introspection. If we’d preserved such knowledge better, the epiphany of perspectives that Wilson inspired in the late 1970s wouldn’t be so few nor so far between.

*

This piece was first published in *The Copernican* science blog on August 6, 2013.

Dear Mukunth,

Thanks for your writeup on Wilson and infinity.

Matscience, our Institute, knew about Wilson’s demise the day after it happened. One of my colleagues Ronojoy Adhikari is planning to hold a 1 day meeting honoring Wilson (perhaps followed by a short course on RG that Wilson developed). Two colleagues from India, H R Krishnamurthy (IISc, Bangalore) and A. Harindranath (SINP, Kolkatta) were Ken Wilson’s Ph.D. students at Cornell. Belal Baaquie at National University of Singapore and a friend of many of us was also a student of Ken.

Most of my colleages in physics are familiar with RG methods, as a standard tool in theoretical physics. H Sharatchandra, who recently retired from our faculty, is an expert on Wilsonian methods.

Leo Kadanoff, whom you refer to, came up with a beautiful idea of block spins and scaling, which Wilson used in a deep and creative way and developed RG methods. Wilson gives due credit to this foundational work. Leo lectured for us at a summer school at Sitges, Spain, back in 1976 on RG methods and lattice gauge theory. Now Leo is a colleague of mine at Perimeter.

As RG method was just being developed, we graduate students at IISc, Bangalore were fortunate to listen to the new theory in 1973 from Michael Fisher. The famous 4 – epsilon method was invented by Fisher and Wilson. I also had the pleasure of having Rajaram Nityananda (who was director of TIFR at Hydrabad until recently and now at IISER, Pune) as my fellow graduate student, who taught me, among other things, all about real space RG methods.

As far as infinity that you write about I can confidently say that `My comprehension is infinitesimal about infinitey’.

with best wishes,

g baskaran

Dear Mukunth,

Thanks for your writeup on Wilson and infinity.

Matscience, our Institute, knew about Wilson’s demise the day after it happened. One of my colleagues Ronojoy Adhikari is planning to hold a 1 day meeting honoring Wilson (perhaps followed by a short course on RG that Wilson developed). Two colleagues from India, H R Krishnamurthy (IISc, Bangalore) and A. Harindranath (SINP, Kolkatta) were Ken Wilson’s Ph.D. students at Cornell.

Most of my colleages in physics are familiar with RG methods, as a standard tool in theoretical physics. H Sharatchandra, who recently retired from our faculty, is an expert on Wilsonian methods.

Leo Kadanoff, whom you refer to, came up with a beautiful idea of block spins and scaling, which Wilson used in a deep and creative way and developed RG methods. Wilson gives due credit to this foundational work. Leo lectured for us at a summer school at Sitges, Spain, back in 1976 on RG methods and lattice gauge theory. Now Leo is a colleague of mine at Perimeter.

As RG method was just being developed, we graduate students at IISc, Bangalore were fortunate

to listen to the new theory in 1973 from Michael Fisher. The famous 4 – epsilon method was invented by Fisher and Wilson. I also had the pleasure of having Rajaram Nityananda (who was director of TIFR at Hydrabad until recently and now at IISER, Pune) as my fellow graduate student, who taught me, among other things, all about real space RG methods.

As far as infinity that you write about I can confidently say that

`My comprehension is infinitesimal about infinitey’ .

with best wishes,

g baskaran