Catalogue 38, Part 3 - Jeremy Norman's HistoryofScience.com

mechanics to visible and tangible objects. In the fifth
section of his paper (p. 812), he set forth the “quite
burlesque” case of a cat
penned up in a steel chamber, along with the following
diabolical apparatus (which must be
secured against direct interference by the cat): in a
Geiger counter there is a tiny bit of radioactive
substance, so small, that perhaps in the course of
the hour one of the atoms decays, but also, with
equal probability, perhaps none; if it happens, the
counter tube discharges and through a relay
releases a hammer which shatters a small flask of
hydrocyanic acid. If one has left this entire system
to itself for an hour, one would say that the cat
still lives if meanwhile no atom has decayed. The
psi-function of the entire system would express
this by having in it the living and dead cat (pardon
the expression) mixed or smeared out in equal
parts.
It is typical of these cases that an indeterminacy
originally restricted to the atomic domain
becomes transformed into macroscopic indeterminacy,
which can then be resolved by direct observation.
That prevents us from so naively accepting
as valid a “blurred model” for representing reality.
In itself it would not embody anything unclear or
contradictory. There is a difference between a
shaky or out-of-focus photograph and a snapshot
of clouds and fog banks (Schrödinger, “The present
situation in quantum mechanics,” translated
by John D. Trimmer [Proceedings of the American
Philosophical Society 124 (1980): 323-38]).
This conclusion sets forth what has been called the
principle of state distinction: “states of a macroscopic
system which could be told apart by a macroscopic
observation are distinct from each other whether
observed or not” (Moore, p. 308). Schrödinger’s paper
represents “his definitive statement about the theory
that he and Heisenberg had discovered” (Moore, p.
307). Moore, Schrödinger: Life and Thought, pp. 306-9.
40521
From One of the Founders of
Modern Geology
95. Sedgwick, Adam (1785-1873). Two autograph
letters signed to [James] Marshall. Dent
[Yorkshire], Oct. 7, 1857; Trinity College [Cambridge],
Oct. 31, 1857. 8pp. total. 186 x 113 mm.
Light soiling along folds, but very good. $950
Letters with excellent scientific content from one
of the founders of modern geology. Sedgwick was
responsible for defining the Devonian and Cambrian
ages in the geological time scale, and his immensely
popular lecture courses on geology, delivered annually
at Cambridge between 1819 and 1870, had an enormous
influence on succeeding generations of English
geologists. One of his students was Charles Darwin,
who began attending Sedgwick’s lectures in January
1831 and accompanied Sedgwick on a geological field
tour of Wales the following summer. The two men
remained friends until Sedgwick’s death, even though
Sedgwick was never able to accept Darwin’s theory of
evolution by natural selection.
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