l8 INTRODUCTORY- Brownian motion, received* May 11. This was a direct outgrowth of his thesis
work (5d). - The first paper on special relativity, received* June 30.
- The second paper on special relativity, containing the E = me^2 relation,
received* September 27. - A second paper on Brownian motion, received* December 19.
There is little if anything in his earlier published work that hints at this
extraordinary creative outburst. By his own account, the first two papers he ever
wrote, dating from 1901 and 1902 and dealing with the hypothesis of a universal
law of force between molecules, were worthless (4a). Then followed three papers
of mixed quality (4c, 4d) on the foundations of statistical mechanics. The last of
these, written in 1904, contains a first reference to the quantum theory. None of
these first five papers left much of a mark on physics, but I believe they were very
important warming-up exercises in Einstein's own development. Then came a
year of silence, followed by the outpouring of papers in 1905.1 do not know what
his trains of thought were during 1904. His personal life changed in two respects:
his position at the patent office was converted from temporary to permanent status.
And his first son was born. Whether these events helped to promote the emergence
of Einstein's genius I cannot tell, though I believe that the arrival of the son may
have been a profound experience. Nor do I know a general and complete char-
acterization of what genius is, except that it is more than an extreme form of talent
and that the criteria for genius are not objective. I note with relief that the case
for Einstein as a genius will cause even less of an argument than the case for
Picasso and much less of an argument than the case for Woody Allen, and I do
hereby declare that—in my opinion—Einstein was a genius.
Einstein's work before 1905 as well as papers 2, 3, and 6 of that year resulted
from his interest in two central early twentieth-century problems, the subjects of
Part II of this book.
The first problem: molecular reality. How can one prove (or disprove) that
atoms and molecules are real things? If they are real, then how can one determine
their size and count their number? In (5a), there is an introductory sketch of the
nineteenth century status of this question. During that period the chemist, member
of the youngest branch of science, argued the question in one context, the physicist
in another, and each paid little attention to what the other was saying. By about
1900 many, though not all, leading chemists and physicists believed that molecules
were real. A few among the believers already knew that the atom did not deserve
its name, which means 'uncuttable.' Roughly a decade later, the issue of molecular
reality was settled beyond dispute, since in the intervening years the many meth-
ods for counting these hypothetical particles all gave the same result, to within
small errors. The very diversity of these methods and the very sameness of the
* By the editors of Annalen der Physik.