Athens, 330 BC

Dear Plato,

I am writing to you because, as my former mentor and teacher, you will
no doubt rejoice at the success of some of the ideas of one of your
pupils. I have to warn you that what I am about to recount is a dream
I had last night, and may be construed as wishful thinking on my
part. However, the dream was so vivid that I believe that what
happened in it will come to pass, even though this will take well over
2000 years.

Last night, I had a dream that took me to a year the people around me
referred to as 2011 AD. I was standing in front of a large building
located in a land that our explorer Pytheas calls Thule. Don't ask me
why, but I knew that the building I entered through doors that opened
by themselves was a descendant of your Academy and of my Lyceum. Young
men and women were obviously there to learn in large numbers. This
heritage is already something the two of us should be proud of, but it
is not what I wanted to tell you most.

As you know, I consider the development of logic one of my main
contributions to human knowledge. I was always a bit miffed by the fact
that many people consider logic a very abstract subject with no
applications. In my heart, I always felt that logic ought to be the
foundation of science, be it basic or applied. I now know that my
beliefs will be vindicated within 2300 years and in spectacular
fashion.

I know that you will find it hard to believe, but in 2011 humankind
will have at its disposal a machine like no other. It is an object
they call "computer", which, unlike any other man-made machine, can be
told to do many different things by feeding it with appropriate
instructions. In 2011, computers will be everywhere. I saw many with
my very eyes, but most of them will also be embedded in physical
devices, and are therefore invisible to their users. By 2011, this
population of "effectively invisible" computers will be in the fabric
of our homes, shops, vehicles, farms and some even in our bodies! They
will help humankind command, control, communicate, do business, travel
and entertain themselves. And you know what? All of this will have to
do with logic!

This truly wonderful machine, the computer, will be an engine of
logic. Logic, my beloved creation, will be used to construct computers
and to breathe life into them. I was told by people in what they call
the "School of Computer Science at Reykjavik University" that the
design of such a complex machine is only possible because George Boole
(a follower of our ideas) invented a simple logic, now called Boolean
logic, which deals with the truth and falsity of simple propositions
and is the basis of modern digital computer design. Moreover, the
languages that future humans will use to communicate with those
machines, which they call "programming languages", are themselves
special kinds of logical systems. Programming computers will make
logic come alive.

You will no doubt remember my famous syllogism:

All men are mortal.
Socrates is a man.
Therefore Socrates is mortal.

Today, people that call themselves "computer scientists" view
syllogisms like the one above as basic steps of computation, which
computers carry out at amazing speed and that take place while the
computers are doing their job. But this is not all. You might recall that
some of my lesser known work dealt with what I called "temporal
logic". In a temporal logic, we can express statements like "I am
always hungry", or "I will eventually be thirsty", or "I will be hungry
until I eat a peach". Well, in 2011 people at this institution of
learning in the Thule, like many others throughout the world, will be
using this creation of mine to describe properties that computer
systems must exhibit, such as "the computer system will never stop
working." Another creation of mine, modal logic, lies at the heart of
applications of logic to reasoning about possible and necessary
behaviour of computing agents. Moreover, computers can be instructed
to check whether other computer systems have properties that can be
expressed using temporal logic!

There is a lot more I could tell you, but I do not want to bore you
more with the contents of this dream of mine. Indeed, I am sure that
you will have already realized why this dream has made me proud. In
fact, I hope that soon I will have a dream showing me the development
of this science in 2050. Even in 2011, computer science will be a young
field and its marriage with logic is bound to produce amazing changes
to human life and to science as a whole. Indeed, during my visit to
that university, I was told that Donald Knuth, a famous computer
scientist, said that: "Science is what we understand well enough to
explain to a computer. Art is everything else we do." So, science is
everything that can be expressed in terms of logic, and in particular
the living logic that runs in computers!

Before waking up, I had a glimpse at something they call a "movie",
where talking images resembling real life are projected on a
screen. In fact, in 2011, computers will also be used to great effect
to make movies, games and many other forms of entertainment. I wonder
what our playwrights would be able to achieve, if they had access to
such a technology.

The movie I watched was entitled "Twins". I did not find it good, but
in it an actor by the name of Arnold Schwarzenegger utters the following
memorable sentence while talking to a thug: "You have no respect for
logic.  I have no respect for people who have no respect for logic."
He then proceeds to beat up the thug, an act that I abhor. But at that
point I woke up, knowing that in 2011 logic will be the most applied
branch of mathematics. All this, thanks to the young damsel called
computer science.

I hope you are resting well in the world of ideas.

Your former pupil,

Aristotle