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have no clue (from form or color) about its age or time of entry into the bag.
This system corresponds point for point with Lyell's vision of the fossil
record in a world of time's stately cycle. The five days are the broad eras of
geological time (few in number); the brands are marks of historical
uniqueness, but (please note) not of progress, for each bean is distinct and all
are equivalent in merit. The entrance of a bean every two minutes marks the
stately uniformity of rate; the random removal of an old bean at each
entrance maintains the steady state of diversity.
The grand beanmaster now sets us a problem. He took an x-ray of the bag
every six hours during the last day, but he forgot to mark the times on his
negatives, and he wants us to arrange the four photos (for midnight, six A.M.,
noon, and six P.M.) in proper temporal order. He is also willing to give us the
bag as now constituted at day's end. How can we proceed?
Lyell and his student Simplicio consider the problem. Simplicio, ever in
search of the easy way, suggests that they look for a crucial bean in each
photo. But Lyell responds that no such object can exist. The uniqueness of
each bean is, perversely, absolutely no guide to its age. Lyell castigates
Simplicio for laziness, and argues that the problem can only be approached
statistically.
Fortunately, the wily beanmaster has provided one criterion that can resolve
this dilemma of history under time's cycle—he has given us the bag in its
present state. Consider, Lyell advises, how the beanmaster proceeded on the
last day. Every two minutes, or 720 times during the day, he put in a new
bean and removed one from the bag at random. We now open the bag. It is
dominated, we reason, by beans added during the last day—not all 720, of
course, because some have been removed by luck of the (with) draw. But,
Simplicio complains as he begins to catch on, we can't tell from the
signatures which beans represent the last day's additions, for a signature
contains no information in se about time.
Lyell then proposes his statistical criterion. We cannot know when any
particular bean entered the bag, but we can make a list
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