We can never know everything
about anything. No matter how narrow
our focus or determined our effort, there will always remain unknowns. Our
information is never complete; the gaps in our knowledge stubbornly persist. It
is this fact that drives us to conduct experiments; to ask questions of the
Universe and compare the answers with our best predictions, to see how close we
are for now.
But the Universe is vast, and our reach comparatively minute.
How do we know if we have asked the right question? Or gathered enough data?
How do we know when we have observed a sufficient number of meteors, for
example, before we can say anything
about them, with confidence? Perhaps all of our observations on meteors are
peculiar to this remote location of our solar system, or local group, or galaxy.
How do we quantify our confidence? How can we ever know for sure?
What if we only had one
example of a thing? Found just one
meteor, or experienced just one hurricane?
What can we learn from a sample size of one?
Before we answer we need to consider exactly what it is we
are trying to learn, and the nature of the thing to be sampled. For example, if
we are trying to learn the best time to pick and eat a newly discovered fruit,
a sample size of one is inadequate. Even if our fruit tasted good (or bad), we
wouldn’t know if it’s flavor improves or worsens given more time. The inherent
variation in fruit flavor, ripening time, etc., makes it impossible to
determine the optimum time to pick from a sample of just one. Now consider
trying to determine if our soup is properly salted. We only need a single taste
to find out. Why? The principle of diffusion, and the properties of dissolved salt,
guarantees that every sample will have nearly the same amount, so a sample size
of one is all we need.
Considerations like these are not trivial, they are
essential when we consider bigger questions such as “What will life on other worlds
be like?” Science fiction has offered up numerous hypothetical life forms
spanning a range from bipedal, bilaterally symmetrical, hominids (complete with
two eyes, a single nose, a mouth and ear, and all in the right place) to life as
a formless, boundless “pure energy” capable of traveling back and forth through
time. Given this apparent “the-sky’s-the-limit” attitude, how can we know what
we are looking for? Couldn’t life easily escape our notice? If not for their
clever camouflage but for our own inadequate means of detection? Couldn’t a
time-traveling organism of pure energy be sitting right behind me, looking over
my shoulder as I type these words, and go unnoticed? Doesn’t our sample size of
one (one planet, one life1) fundamentally
handicap our attempts at finding life elsewhere in the Cosmos? How do we build
a “life-detector” if we don’t know what we are looking for?
You may be surprised to learn that we do have an idea of
what to look for, as well as when and where. Our “life-detector” is fined tuned
to look for life within very narrowly defined limits. And it’s not likely to
miss the invisible, time-travelling, pure energy aliens, because there aren’t
any.
1One look at the diversity of life on this planet
gives the false impression that we are surrounded with millions of samples of
life. We are not. All living things, past and present, are modifications on a
single theme of life. The essential living machinery –the hardware, appeared
only one. But the software of the genetic code has been repeatedly modified.
Just as there can be many different types of guitars, each playing many
different tunes, there is only one type of instrument called “guitar”. If we
wish to enumerate the instances of “life” on this planet, the total is just
one.
Copyright 2013 by theBIOguy
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