Alan Turing

Last Saturday was the 100^th birthday of Alan Turing. Who, you ask? Thomas McDonald has a good overview of his life and contributions. Wikipedia has a more in depth biography. Any student of Computer Science will learn about Turing at some point. He defined what came to be known as the Turing Machine, which is not a physical machine at all, but a thought experiment to determine what is the simplest thing a machine can do that, if given enough time, can allow it to do anything that any machine that could ever be built can do. His contributions are the basis of computability theory that are still taught and used today.

But I'd like to talk about his brilliant paper Computing Machinery and Intelligence. In it he proposes what has come to be known as the Turing test. The basic idea is this. Three people are conversing via some mechanism that does not give away any information about who the person really is (such as chat). Call them "Alex", "Brooke" and "Chris." One of the other two (Alex or Brooke) is really a machine. Chris asks questions, and by the answers given, tries to tell which is the machine, and which is the human.

The claim is that if there is no discernible difference between the human and the machine, the machine exhibits intelligence. Whether or not the machine is intelligent is a deeper question, and one which Turing sort of glosses over. But his point is valid. If there is no way to determine that the machine is different from something we know is intelligent, then it becomes hard to claim that the machine does not possess intelligence.

Note that Turing makes no assumptions about the size, shape or construction of the machine. It could be a smart phone or a room full of gears. It can look up answers in a book or roll dice. The only thing we can examine is the output on the screen. This sort of reminds me of "The Turk", which was a fake chess playing "machine" built in the late 18^th century. In that case though, it was a human masquerading as a machine (which is an easier problem).

In each case, the claim is that the "implementation" is equivalent as long as the "observations" are equivalent. In general that may be so, but it is not the case when we talk about specifics. If I am chatting with my son, for instance, it makes a huge difference whether it is really my son on the other end, regardless of how clever the imitator may be.

I bring this up because I see the Turing test as an analogy to the Eucharist. In distinguishing intelligence from all of the external signs, Turing inadvertently distinguishes the accidents (observations) from the substance (implementation), a la St. Thomas Aquinas. Through all the "observations" we can make, we can only detect bread and wine. Some might claim that's all the reality there is, or that it doesn't matter what is really going on because all we can observe is bread and wine. However, to those who have a love of the person of Jesus, it matters deeply whether the "implementation" is bread and wine or the body blood soul and divinity of Christ.

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Eureka

I confess, one of the shows I follow on TV is the SyFy channel original series Eureka. Yes, it is often hokey, and the science is bogus, and the alternate universe stuff gets annoying, but for whatever reason, I find it enjoyable. So there. Besides, it's in its final season. Warning, here come spoilers.

If you've been watching recent episodes, you know there was an experimental FTL (faster than light) spaceship that disappeared with the crew on board. It turned out that the ship never left the Earth, but the crew was kidnapped and put into a virtual reality machine (ala The Matrix). They discover they are in a virtual reality when there are glitches. In one case a bird flies through a rock. In another, the NPC (non-player character) becomes pixelated or flickers. When the characters see this they realize that this is not "reality" but a virtual reality inside the real world.

In the movie "The Matrix" the "proof" that there was a deeper reality than what was seen is even more subtle. Things like seeing the same cat cross a room twice. Experiencing deja vu is also "proof" of a reality deeper than what can be seen.

It strikes me that despite the banishment of all thing religious from both story lines, there is something very Christian about these stories. We see things that defy the laws of nature (aka miracles) and point to them as evidence of a deeper spiritual reality than just the physical one we experience with our senses normally.

As Catholics, we believe, as the Disciples and Church Fathers did, that Christ meant what he said in John 6, and in the synoptic Gospels, where He said [emphasis mine] "this is my body" "this is my blood". And so we believe that each mass is itself a miracle, in that the bread and wine actually become the body and blood of Christ, but the appearances do not change.

But sometimes they do. The image at the top of this post is of the Miracle of Lanciano, which took place around the year 700 in what is now Italy. What you are looking at is a consecrated host, which contains a perfect cross section of a human heart, complete with all the expected structures. My atheist friends say that miracles are just low probability random events that we impose our superstitious meanings on, but how does one explain this?

This is not just a "low probability event", it defies anything plausible. Even assuming an evil priest who wanted to trick everybody into his wrong-headed ideas, who had the technology to merge bread and human heart 1,300 years ago? Or even to produce a perfect, undisturbed slice? And how does one explain that, of all the miracles involving Christ's blood over thousands of years, every one has turned out to be blood type AB. Blood type AB occurs in only 5% to 10% of the population, so the probability of choosing someone with that blood type so many times in a row itself is highly unlikely. And since blood types were only discovered in the last century, there is no way our ancient priest could have tested for it.

Certainly miracles are neither necessary for nor sole proof of our faith, but they do present a dilemma for those who will not believe. As G.K. Chesterton, wrote in Orthodoxy, "The believers in miracles accept them (rightly or wrongly) because they have evidence for them. The disbelievers in miracles deny them (rightly or wrongly) because they have a doctrine against them."

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