The second law of thermodynamics is the one that means there can be no
perpetual motion machines. If it is possible to circumvent the second law
by intelligent design, why is it not possible to intelligently design
a perpetual motion machine?
Another example: at certain latitudes (the norther U.S., for instance), ponds
freeze over every winter. The same ponds thaw every spring. There is an
entropy change from frozen-pond to thawed-pond. For the purposes of this
example, it doesn't matter which way is which. The reality is, though, that
the pond freezes, thaws, freezes, thaws, meaning it first increases its entropy,
then decreases it, and so forth. How can this be? Well, there is this big
glowing thing in the sky which we call the sun... :-) Energy from the sun
hits the pond, and means that the pond isn't a closed system, so the second
law doesn't apply to it. The second law only applies to the pond *AND* the
sun (which is increasing its entropy so fast it hurts to look at it :-)).
The same is true for any system on earth--its interaction with that big glowing
thing in the sky can't be overlooked in trying to apply the second law to it.
-Greg