164 RELATIVITY, THE SPECIAL THEORYWhy, on the whole, was Einstein so reticent to acknowledge the influence of the
Michelson-Morley experiment on his thinking? Why could Lorentz never quite
let go of the aether? Why did Poincare never understand special relativity? These
questions lead us to the edge of history.
It is natural to suppose but wrong to conclude that the use of the term the edge
of history implies that its user has a clear picture and sharp definition of what
history is. History deals with happenings in the past. The history of a period is
an account of that period based on a selective sampling of dates and facts from a
pool of information which, it is safe to assume, is incomplete. The selective factor
is necessary as well as unavoidably subjective. Therefore one cannot speak of the
history of a period. An historian can definitely be wrong but often cannot be sure
of being right. That much is clear. Also, the knowledge of selected facts and dates
is necessary but not sufficient if one is not content—and one should not be—with
some insight into what happened but wishes to inquire further how 'it' happened.
In the case of the history of discovery, questions like, Why did A create what he
did, why did B readily accept what A created, why did C resist A's new ideas?
are fascinating. In my many years of immersion in theoretical physics I have
known A's, B's, and C's. Though their concerns may not have been as profound
as relativity, I often found it baffling to answer such questions as those just raised.
Creation, acceptance, and resistance, whether in science or in other areas, are acts
and attitudes the whys of which can be grasped only if one knows, along with
facts, how the minds of A and B and C work. Who knows whether he knows?
However, while the answers to the A-B-C questions are elusive and deliriously
conjectural, the same is not necessarily true for the questions themselves. Return-
ing to Einstein, Lorentz, and Poincare, the questions I raised about them are the
result of patient reading of their papers. The questions themselves are therefore
distilled from an historical record, and I do not think it is at all bold to call them
part of history. Their answers, it seems to me, are beyond history. Somewhere
between the question and the answer lies history's edge, a term I have now defined
with more precision than history itself. In what follows I shall not entirely refrain
from indulging in a bit of extrahistorical speculation regarding the answers.
First, however, a few more facts.
- Einstein and the Literature. Einstein's 1907 article [El] for the Jahrbuch
der Radioaktivitat und Elektronik was written at the invitation of Johannes Stark,
the founder and editor of that series. In agreeing to review relativity theory, Ein-
stein wrote to Stark, 'I should note that unfortunately I am not in a position to
orient myself about everything that has been published on this subject, because
the library is closed in my free time. Apart from my own papers, I know of a
paper by Lorentz (1904), one by Cohn, one by Mosengeil, and two by Planck.*
I would be much obliged if you could point out further relevant publications to
me, if such are known to you' [E2]**. This letter, as well as an earlier one to
*A11 these papers are referred to in Chapters 6 and 7.
**This letter was published in an article by Hermann [HI].