318 Are the Androids Dreaming Yet?
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318 Are the Androids Dreaming Yet?
Uncertainty
If youknow alittle of quantum mechanics you might imagine Heisenberg’s
Uncertainty Principle comes to our rescue.
Heisenberg’s principle is often misunderstood. People sometimes
try to explain it as an experimental problem. If I want to measure the
position ofa particle I am going to need to shine a light on it. The photons
I use to illuminate the particle will knock it out of position so the act of
measurement disturbs the system. This is not the Uncertainty Principle.
It is a different but related effect, called the measurement problem. The
muddle is really Heisenberg’s own fault. When he tried to produce a
layman’s explanation he used the analogy of disturbing the particle with
the photon. This is wrong. A photon would not disturb a particle enough
to explain the uncertainty we find; particles are fundamentally uncertain
even before we measure them. Heisenberg’s Uncertainty Principle is
a quantum property, which means it makes no sense and there is no
analogy I can give you to properly explain it! Here is the closest thing I
can find.
Imagine I am playing a musical note on a guitar. You might want
to know two things about it; where exactly is the string and what pitch,
or note, am I playing? The problem with these two measurements is they
can't be stated at the same time. Pitch is dictated by the rate of oscillation
over time: the number of times a string vibrates back and forth per
second. Position is the exact location of the string at a given moment in
time. IfI state the position precisely this has no pitch because pitch needs
a time interval. If I allow a time interval the string will move during that
time and it won't be precisely in one place. The best I can say is the string
is about two millimeters above the fret board and two-thirds of the way
across it.
So, I hear you cry, this Uncertainty Principle means our Universe is
not deterministic because it is uncertain.
Unfortunately, the principle only prevents us from measuring the
position and momentum ofa particle at the same time, it does not prevent
the Universe knowing the information it needs to allow the particle to go
about its business in an entirely deterministic fashion. There is a perfectly
reliable and predictable wave function that governs the motion of every
particle, just as there is an entirely predictable equation for the motion of
a string on a musical instrument.
If both the classical and quantum laws of physics are deterministic
where does the freedom come from to make our Universe non-
deterministic? There is just one place to look: you and me.
HOUSE_OVERSIGHT_016008
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