Thursday, November 16, 2017

What is artificial intelligence

Hal 9000, from the film 2001 a Space Odyssey
Terms such as smart and artificial intelligence are being abused lately. Let’s look at some recent news that have appeared in various media:
  • Smart benches with solar energy free mobile charge, and access to Wi-Fi. These public street benches, installed in London by Ford, incorporate a Wi-Fi repeater and a solar plate that gives them power to charge a mobile phone battery. Where is the intelligence in the bench? Nowhere. The intelligence belongs to the human being who invented these devices. In a similar case, we would be saying that our houses are smart because they have electricity and an Internet connection.
  • China implements smart trash cans. In this case the waste bin also incorporates a solar panel connected to a mobile phone charger. In the future they will also have a Wi-Fi repeater and a device to disinfect the garbage with ultraviolet rays. As in the previous case, the mere presence of an electrical or electronic device is confused with intelligence.
  • Goodyear tests a tire that predicts when it must be changed. The tire has a built-in wireless sensor that detects when it needs to be replaced and issues the corresponding warning. Although this case is somewhat more complex than the previous two, something is again called smart when it isn’t. To implement this, you just need a sensor and a simple electronic device, more or less equivalent to those radio devices that since decades have been incorporated to wild animals, to follow their displacements and watch their activities.
As you can see, what is now called smart is just what was formerly called automatic. But of course, the word smart is more appealing, that’s why it’s being abused. In the same way, there is a tendency to call artificial intelligence what formerly was called computer science.

Thursday, November 9, 2017

The Pascal wager and the Smith wager

Blaise Pascal
Blas Pascal (1623-1662) is known for his activity in mathematics (he devised the triangle of Pascal), physics (he proved the principle of Pascal, invented the hydraulic press and experimented with atmospheric pressure) and especially for his Pensées (Thoughts) one of which contains the first known example of the use of game theory, whose theoretical development had to wait until the twentieth century. This example is the famous Pascal wager, which he expressed thus:
Dieu est ou il n’est pas. Mais de quel côté pencherons‑nous?... Pesons le gain et la perte en prenant croix que Dieu est. Estimons ces deux cas: si vous gagnez, vous gagnez tout, si vous perdez, vous ne perdez rien. Gagez donc qu’il est sans hésiter. 
Whose English translation is:
God exists or He does not exist. Which side shall we take?... Let us weigh the gain and loss, assuming that God exists. Let us consider both cases: if you win, you win everything; if you lose, you lose nothing. So you must wager, without doubt, for His existence.

Thursday, November 2, 2017

The end of mankind

Lord Kelvin
In an earlier post in this blog I spoke about the myth of the Enlightenment, which gave rise to the theory of indefinite progress and the forecast of enormous advances for humankind that would be within our reach in the not too distant future. Although the first half of the eighteenth century was a brake on almost all the cultural activities of our civilization, including science, they were delighted with themselves. Friedrich Melchior, Baron von Grimm (1723-1807), expressed it with unequaled candor, in these words [1]:
The eighteenth century has surpassed all the others in the praises it has lavished on itself.
One of the ideas in vogue by that time was the assumption that scientific advances would let man reach immortality, not too far in time. Although the idea, as a distant possibility, goes back to Roger Bacon, it seemed much closer in the late eighteenth century. Hence the anecdote told of the octogenarian wife of marshal Villeroi, who exclaimed, while looking at Professor Charles’s ascent in a hydrogen balloon:
Yes, it is true! They’ll discover the secret of not dying, after I’ll be dead!
The optimistic ideas of the eighteenth century suffered a sudden, impressive turn in the nineteenth, when came to dominate a pessimistic vision of the future of mankind, based mainly on two scientific discoveries:

Thursday, October 26, 2017

Some clarifications on the cosmic background radiation

In 1948, Ralph Alpher and Robert Herman (both in George Gamow’s team) came to the conclusion that if the universe had come out of a Big Bang and had expanded since that point in time, there should exist a cosmic background radiation in the frequency of microwaves (or what means the same, at a temperature of about 5K, 5 degrees above absolute zero). Alpher and Gamow had published that same year another prediction about the average composition of the cosmos, starting from the Big Bang theory.
In 1964, Arno Penzias and Robert Wilson were working with a newly built very powerful radio telescope and detected a background noise that could not be eliminated. First they thought that it would be of terrestrial origin, but once all the possible sources of noise had been taken into account, the effect persisted. Then they came to the conclusion that such noise could not come from the solar system or from our galaxy (for in that case it would be more intense in one direction than in another), and that its origin had to be cosmic. The temperature of that radiation (that is, its frequency, considering the Wien equation) turned out to be about 3K. Robert Burke of MIT suggested to Penzias that such noise could be the cosmic background radiation predicted by Alpher and Herman. This was in fact confirmed. For their discovery, Penzias and Wilson received the Nobel Prize in 1978.
Along with the argument based on the average composition of the universe, the cosmic background radiation gave the accolade to the Big Bang theory, which became the standard cosmological theory (although see an earlier article on this blog).

Thursday, October 19, 2017

Virtual particles

Werner Heisenberg
Heisenberg's uncertainty principle, one of the consequences of quantum mechanics, makes possible the birth of virtual particles in the void, apparently transgressing the principle of energy conservation, the most holy in physics. The reason is that Heisenberg’s principle can be expressed in several ways, one of which relates the uncertainty about the energy to the uncertainty about time:
This expression can be interpreted in the sense that a pair of objects, each with energy E, can appear spontaneously in the vacuum, provided that they lasts at most a time Dt<ħ/(2E). These pairs of objects are called virtual particles. One of these particles is always matter, the other antimatter, and their duration, according to this principle, is ridiculously small. A virtual electron, for instance, would last 1.3×10-21 seconds (just above one sextillionth of a second). The higher the mass (energy) of the virtual particle, the less time it will last. After that time, the two particles will annihilate each other and disappear. Due to their short duration, the existence of virtual particles has not been experimentally verified.
Is it possible for these virtual particles to become real under certain circumstances? Yes it is, and it is believed that there are at least two situations (somewhat drastic, it is true) where this could happen.

Thursday, October 12, 2017

Is physics losing touch with reality?

In his famous posthumous book The Discarded Image, published in 1964, a few months after his death, C.S. Lewis shows he is ahead of his time by predicting a situation that today, when it has become usual in physics, gives a rather bad forecast for the future of this science. Let’s look at a relevant quote:
The mathematics are now the nearest to the reality we can get. Anything imaginable, even anything that can be manipulated by ordinary (that is, non-mathematical) conceptions, far from being a further truth to which mathematics were the avenue, is a mere analogy, a concession to our weakness. Without a parable, modern physics speaks not to the multitudes. Even among themselves, when they attempt to verbalise their findings, the scientists begin to speak of this as ‘making models’... Sometimes [the models] illustrate this or that aspect of [reality] by an analogy. Sometimes, they do not illustrate but merely suggest, like the sayings of the mystics... By accepting [an expression such as] the ‘curvature of space’ we are not ‘knowing’ or enjoying ‘truth’ in the fashion that was once thought to be possible.

Thursday, October 5, 2017

Scientific mistakes in Planet of the Apes

In 1963, the French writer Pierre Boulle published a famous science-fiction novel titled Planet of the Apes, which was adapted to the cinema for the first time in 1968, with Charlton Heston as the protagonist and script by Michael Wilson and Rod Serling, the latter famous for the TV series The Twilight Zone. A decade earlier, Boulle had published another bestseller, also successfully adapted to the movies: The Bridge over the River Kwai.
Boulle’s novel tells the story of three astronauts embarking on a two-year journey (measured in relativistic time) to a planet revolving around Betelgeuse (alpha of the Orion constellation) and find there an extraterrestrial civilization at a level similar to ours in the mid-twentieth century, where intelligent beings are three species of apes (identical to the terrestrial gorillas, chimpanzees and orangutans) while human beings (also identical to us) are devoid of reason. Of course, the only surviving terrestrial astronaut finds it very difficult to convince the apes that he is an intelligent being.