"Babies and young children think, observe, and reason.
They consider evidence, draw conclusions, do experiments, solve
problems, and search for the truth" . Like anyone else, I was a scientist
at birth. I have since continued to cultivate my natural curiosity
and desire to explore. Thus, while I am frequently in search
of answers, their lure magically disappears as soon as they have
been found. Answers are satisfying when they are the bridge to
further questions. Luckily they often are.
Cultivating one's curiosity is not always easy. School, as
one can read in many of the learning stories available on the
LDI Web site (see the Learning
Stories Research project) as well as in the biographies and
autobiographies of a good many scientists (in the framework of
LDI's "The Scientific Mind"
[TSM] project I get to read quite a number of them), is often
a factor that must be overcome, rather than what it also could
be: a facilitator. Elements in the environment - the presence
of a friend, sibling, or other close or not so close relative;
finding the right book; the visit to a science museum; or participation
in an environment where kids can get involved in explorations
and experiments - may be crucial.
In my case, important factors were the presence, at an hour's
walking distance from my childhood home, of a flee market, open
on Saturday afternoons, where, out of whatever little money I
had been able to accumulate, I could buy used radio parts. More
strongly appealing to my imagination, and at much closer distance
from home, was a well-stocked retailer of new electronic components.
Everything imaginable was there on display behind large windows.
Evening after evening I stood there, staring at the objects of
my desire behind the thick glass. The store issued a free catalogue
every year. I never failed to pick one up when the new edition
was out. It was a great stimulus for "doing science in the
mind" with those things I couldn't buy. The experience must
perhaps have conditioned me to opt later, while studying physics
at the Delft
University of Technology (DUT), to do my degree work in theoretical
physics. DUT being a technological university, the overall orientation
in physics envisions application, rather than the theory behind
it. So, the theoretical specialization was only available after
one had proved to be a good experimentalist. Thanks to that requirement
I got a thorough grounding in both theory and experiment. In
retrospect, I think it may have helped me
I had the privilege of being admitted to the Theoretical Physics
Group headed by Professor Ralph Kronig. He personally supervised
my research. Initially I was the only theoretical physics student
in the whole group, which Kronig had given new life after he
had served for several years as Rector Magnificus (Vice-Chancellor).
When I graduated we had grown into a group of four. Even today's Theoretical
Physics Group at Delft is still very small. There is a distinct
advantage in being part of a small learning community. My work
with Kronig focused on second order effects in the interaction
between electromagnetic radiation and matter. Some of it is reflected
in a joint publication (Kronig &
"Kronig is an eminent physicist and a gentleman,"
writes Abraham Pais in his biography of another great physicist
of the past century, Niels Bohr. (Pais,
1993, p. 244). He refers to one of the bizarre stories in
the history of science regarding the discovery of a key scientific
concept (the electron spin) and the subsequent awkwardness regarding
the attribution of credit for it. Kronig, fresh out of Columbia
University and visiting Europe, had the original idea. He was
discouraged by Pauli from publishing it. A few months later,
two young Dutch physicists, Uhlenbeck and Goudsmit, who worked
with Ehrenfest in Leiden, had the same idea and published it.
Dirac's view on what happened is
Ehrenfest liked the idea very much. He suggested to Uhlenbeck
and Goudsmit that they should go and talk it over with Hendrik
Lorentz, who lived close by in Haarlem. They did go and talk
it over with Lorentz. Lorentz said, "No, it's quite impossible
for the electron to have a spin. I have thought of that myself,
and if the electron did have a spin, the speed of the surface
of the electron would be greater than the velocity of light.
So, it's quite impossible." Uhlenbeck and Goudsmit went
back to Ehrenfest and said they would like to withdraw the paper
that they had given to him. Ehrenfest said, "No, it's too
late; I have already sent it in for publication."
That is how the idea of electron spin got publicized to
the world. We really owe it to Ehrenfest's impetuosity and to
his not allowing the younger people to be put off by the older
Excerpt from a letter, dated
March 25, 1926, by L.H. Thomas to Samuel Goudsmit reproduced
from Goudsmit's account of "The
discovery of the electron spin." (Available on the Website of the Instituut-Lorentz.
The letter was reproduced from a transparency used by Goudsmit
during his 1971 lecture on the above topic. The original is presumably
in the Goudsmit archive kept by the AIP Center for History of
There are, of course, interesting lessons to be drawn from
such experience, for both young and old, particularly as regards
the intergenerational dimension of how people learn and grow
together and how they impact - positively and negatively - on
each other's learning. Peer review - informal in this case and
certainly not blind - is another issue that comes to mind. I
have always found Kronig's gentlemanlike behavior - as referred
to by Pais - in this context exemplary and believe that setting
examples in relevant matters is a key pedagogical issue. I owe
much to Kronig in this regard. For further reading about this
fascinating story, see also Sin-itiro Tomonaga's (1997) "The Story of Spin" and the Website
of the "Instituut-Lorentz."
The latter source also features a link to Goudsmit's version
of the story, which focuses, among other aspects, on the importance
of the cumulatively constructive process of building knowledge.
A letter by Uhlenbeck and Goudsmit to Nature on "Spinning
Electrons and the Structure of Spectra", published in
Volume 117, pp. 264-265 (February 20, 1926), is equally of interest.
So is, for readers who master the Dutch language, Kronig's
obituary by Kokkedee. The latter noted the awkwardness that
never a Nobel Prize was awarded for what everyone agrees was
one of the key ideas in the physics of the first half of the
twentieth century. Putting all the different accounts together,
one gets a good feel of the complexity and profoundly human nature
of doing science.
My continued and current interest in science is particularly
motivated by my belief that the mindset of a good scientist -
i.e., a scientist who contributes to creating new insights in
the perspective of building a better world - is an attribute
of the mind that should not only be developed in members of the
scientific community but that can also tremendously benefit members
of the human species in general, whatever their role in life.
This has led me to the idea that contributing to the growth of
the scientific mind is an important
aspect of the development of human learning.
Gopnik, A., Meltzoff, A. N. & Kuhl, P. K. (1999). The
scientist in the crib: Minds, brains and how children learn.
New York: William Marrow and Company,