“The Pioneer spaceship includes a plaque designed to communicate with aliens, if any should ever intercept it.
They may find some parts of it easier to interpret than others. A
radial diagram shows the distance of 14 pulsars and the center of our
galaxy from Sol. Aliens are likely to determine the length of each line
is proportional to the distances to each body. Another diagram shows
humans in front of a silhouette of Pioneer. If Star
Trek gives an accurate conception of alien species, they may
respond, “They look just like us, except they lack pubic hair.” However,
if the aliens’ perceptual system differs greatly from our own, they may
be unable to decipher these squiggles.
What would happen if we tried to communicate with aliens by transmitting
a computer program? In the movie Independence Day, the heroes
destroy the invading alien mothership by infecting it with a computer
virus. Close inspection of the transmitted program shows it contains
curly braces; it is written in a dialect of C! It is unlikely that alien
species would program in C and unclear that aliens could decipher a
program written in C if presented with one.
What about lambda calculus? Propositions as Types tell us lambda
calculus is isomorphic to natural deduction. It seems difficult to
conceive of alien beings who do not know the fundamentals of logic, and
we might expect the problem of deciphering a program written in lambda
calculus to be closer to the problem of understanding the radial diagram
of pulsars than of understanding the image of a man and a woman on the
Pioneer plaque.
We might be tempted to conclude lambda calculus is universal, but first
ponder the suitability of the word “universal.” These days, the
multiple-worlds interpretation of quantum physics is widely accepted.
Scientists imagine that in different universes one might encounter
different fundamental constants (such as the strength of gravity or the
Planck constant). But easy as it may be to imagine a universe where
gravity differs, it is difficult to conceive of a universe where
fundamental rules of logic fail to apply. Natural deduction, and hence
lambda calculus, should not only be known by aliens throughout our
universe but also throughout others. So we may conclude it would be a
mistake to characterize lambda calculus as a universal language, because
calling it universal would be too limiting.”
*Philip Wadler
Communications of the ACM, Vol. 58 No. 12, Pages 75-84*
http://cacm.acm.org/magazines/2015/12/194626-propositions-as-types