R Narasimhan Centenary
Prof RN (April 17, 1926 – September 3, 2007) is well-known as the designer and implementor of India’s first digital computer, the Tata Institute of Fundamental Research Automatic Calculator (TIFRAC). He was also the founder of the Computer Society of India. Wikipedia has a comprehensive article about RN that is easily accessible.
However, another
part of his life has been known only to professionals in the field. This part
deals with language behavior, visual pattern recognition, Vision in animals and machines, and Artificial
Intelligence. I will discuss a few significant questions in this research area and
RNs' positions. It is incredible how his views have stood the test of time.
The role
of syntax
RN pioneered
exploring syntactic methods in visual pattern recognition, which was
appropriate to the context in pattern recognition with which he was first
involved—bubble chamber images [RN, 1964] and [RN, 1966]. However, His interest
in vision continued for years [Reddy and RN, 1971], [Barlow et al, 1972].
He was not tied down to syntactic methods.
Soon after
this, he became more interested in natural languages.
Theories
of Language
Noam
Chomsky’s work on transformational grammars was very influential from 1965 to 1985. Chomsky believed language is primarily a formal
system governed by innate structures rather than a repository of encyclopaedic
knowledge.
However, RN
did not fall for the temptation to follow the stream. He recognized the
importance of going beyond syntax and dealing with context, multi-sensory
learning, and the pragmatics of language use. He gave special attention to
language learning by children.
RN stressed
phylogenetic continuity. He found it difficult to believe that language
behavior suddenly appeared in homo sapiens. It is more likely to have evolved
gradually from animal communication.
RN
published two books collecting his work together [RN, 1998] and [RN, 2004].
Limitations
of automated logic
Symbolic AI
focuses on representing knowledge in structures that can be manipulated by a
machine to carry out deduction and induction. This works with toy worlds but
fails to deal with the real world. Can automated deduction go beyond stored
knowledge and explain common sense? RN said no. He accepted the importance of
deduction and induction, but felt that common sense goes beyond these.
RN believed
in paradigmatic behavior, which is driven by analogy.
Geoffrey Hinton, often called the “Godfather of AI,” has recently
offered a provocative perspective on human cognition. In an interview [Hinton, 2025], he has
declared that humans are fundamentally “analogy machines,” not the reasoning
beings we often perceive ourselves to be.
Role of
language in problem solving
As a
Research Associate at the Computer Group at TIFR, I was fortunate to
learn from RN’s work and publications. His special interest in language as a
tool led me to explore “Language-Based Problem Solving” for my thesis, guided
by Prof RN and Prof JR Isaac [Ramani, 1971]. I was working with a computer (CDC-3600) with
much less memory than the cell phone I now use! The idea of language models was
not well developed then, though we were writing programs that spun out stories,
correct in content and grammaticality, based on ad hoc probabilities. Multi-layer
neural networks and the transformer model were decades away. However, I could
implement pattern matching to solve problems by analogizing from a few
examples.
Learning
from the Nervous System
RN was
inspired by the work of Hubel and Wiesel at Harvard.
Their
discovery of feature detectors in the visual cortex of cats supported his
conviction that understanding perception and cognition required a
multidisciplinary approach.
His paper [Barlow
et al, 1972] is memorable,
emphasizing his conviction that studying the human nervous system and human
behavior is essential for progress in AI.
RN’s
unique style:
RN never
had set goals for publication for himself or those he guided. This eliminated
the need to follow research fashions of the day, or to go journal hunting to
find some journal that would accept whatever one had written. Integrity in
research requires that you have truly significant results before you publish. These
principles have made RN’s positions on research issues relevant over the decades.
The coming decade is expected to be an AI decade, with highly accelerated
progress in science, technology, and medicine. I wish that RN were here to
enjoy the progress!
References
[RN, 1964]
Labeling schemata and syntactic descriptions of pictures, R. Narasimhan, Information and Control, Volume 7,
Issue 2, 1964, Pages 151-179, ISSN 0019-9958,
https://doi.org/10.1016/S0019-9958(64)90087-7.
(https://www.sciencedirect.com/science/article/pii/S0019995864900877)
[RN, 1966]
Syntax-directed interpretation of classes of pictures. Communications
of the ACM, 9(3), pp.166-173. 1966.
[Reddy and RN, 1972]
Reddy, V.S.N. and Narasimhan, R., 1972. Some experiments in scene analysis and
scene regeneration using COMPAX. Computer Graphics and Image Processing, 1(4),
pp.386-393.
[RN, 1981]
Narasimhan, R., 1981. A Framework for Modelling Behavior. In Modelling Language
Behavior, pp.1-26.
[RN, 1998]
Narasimhan, Rangaswamy. Language Behavior: Acquisition and Evolutionary
History. India: SAGE Publications, 1998.
[RN, 2004]
Narasimhan, Rangaswamy. AI And the Study of Agentive
Behavior. India: Tata McGraw-Hill Publishing Company Limited, 2004.
[RN, 1997]
Narasimhan, R., 1997. Knowledge processing and
commonsense. Knowledge-Based Systems, 10(3),
pp.147-151.
[Ramani,1971]
Ramani, S., 1971, September. A Language-Based
Problem-Solver. In IJCAI (pp. 463-473).
[Barlow et al, 1972] Barlow, H.B., Narasimhan, R. and
Rosenfeld, A., 1972. Visual Pattern Analysis in Machines and Animals: The same
principles may underlie the operation of sensory neurons, computer programs,
and perception. Science, 177(4049), pp.567-575.
[Hinton,
2025]
Geoffrey Hinton’s interview on April 23, 2025 at the University of Toronto
https://www.youtube.com/watch?v=vpUXI9wmKLc