Quantum mechanics or classical physics?

John Stewart Bell

The debate about which theory explains better the behavior of elementary particles, either quantum mechanics (with strange consequences such as state superposition and quantum collapse) or a still unknown classical physics-type theory that eliminates the need for such phenomena, has been going on since Bohr and Einstein started this debate almost one century ago.

The issue seemed to have been decided when John Steward Bell formulated in 1964 the famous Bell inequality, which I described in another post. However, as some physicists still raise the question, other means of distinguishing between the two types of theories are still being sought. One of them is the Leggett-Garg inequality (LGI), to which I will dedicate this post, based on a recent article in Physics World, dated August 12, 2024.

Time travel in science fiction

H.G. Wells

A few years ago, I published in this blog a series of posts about the scientific aspect of time travel, the paradoxes it could cause if it were possible (which almost certainly it is not) and proposed solutions to these paradoxes, such as the quantum multiverse, one of the most absurd theories physicists have ever concocted. In another post I talked about the scientific errors in Michael Crichton’s sci-fi novel Timeline, which tries to avoid the paradoxes in this way, but does it poorly.

Here I am going to speak about time travel from a literary point of view, as a subgenre of science fiction. In this context, it’s irrelevant that time travel may or may not be possible. We are interested in the question, because this is one of the most frequent topics in this type of literature.

The number of productions of this genre dealing with time travel is huge. I have tried to make a list of the novels and short stories about this issue that I have read (or written), and their number is overwhelming. Furthermore, I am sure I’m forgetting many titles, especially short stories, which are more difficult to remember, as they are distributed among collections and anthologies, sometimes by a single author, sometimes by several. Finally, we should add all the works I haven’t read yet, which are probably even more numerous.

The first problem we should solve is finding a clear definition of the works that belong to this subgenre. The list of works provided by Wikipedia, apart from being incomplete, mixes productions belonging to different genres, such as the following:

•         Legends of sleepers, such as the legend of the monk and the little bird, which appears in cantiga CIII of Cantigas de Santa María by Alfonso X the Wise and in many other sources. A monk falls in ecstasy while hearing a little bird sing, and when he wakes up he discovers that three centuries have passed. In the United States, Washington Irving’s Rip van Winkle is famous, whose protagonist falls asleep one night and wakes up 20 years later. This type of works does not belong to science fiction, because in them there is no science.

•         Magic fiction stories, such as The Goloshes of Fortune by Hans Christian Andersen or The Story of the Amulet by E. Nesbit. For a purist, the two Harry Potter novels where time travel takes place would also fall into this section, but I prefer to include them in science fiction, because magic, in these books, is an analogy of science.

It is also doubtful whether we should classify in this subgenre short stories and novels that do not deal with time travel in the strict sense, but with means of viewing the past. The device used to achieve this is usually called a chronovisor or a chronoscope. I will cite here The Dead Past by Isaac Asimov and my novel A Face in Time, although the latter also belongs to the subgenre of time travel. In Harry Potter and the Chamber of Secrets there is one of these visions through time, although it uses magic, rather than a chronovisor.

The first science fiction story that belongs to this subgenre, as it uses an instrument to travel through time, is the story The Clock That Went Backwards by Edward Page Mitchell (1881). I didn’t like it too much, because the author is influenced by the anti-Spanish black legend in the Netherlands version.

Ray Bradbury

A very special case is the story The Toynbee Convector by Ray Bradbury, which is usually classified in the time travel science fiction subgenre, but could belong to another subgenre. I’m not going to say which, for doing so could spoil the fun for those who haven’t read it yet. I recommend this story, because it’s quite innovative.

Another unique case is Cryptozoic by Brian Aldiss, which combines time travel with a strange theory about time: it asserts that we don’t go from the past towards the future through the present, but rather the other way around. Our existence begins with our death, we live life backwards, and end when the zygote divides into a sperm and an egg within the mother’s womb. This novel caused great controversy among its readers, who were divided between those who judged it to be pure nonsense, and those who considered it a great achievement by its author. In another post I wrote that perhaps Aldiss got the idea from the story The Blind Man's World by Edward Bellamy, where the Martians remember the future and don’t know about the past.

The following table shows the science fiction novels and stories about time travel I have liked best:

Date	Títle	Author	Type of work
1888, 1895	The Chronic Argonauts and The Time Machine	H.G. Wells	Short story and short novel
1950	Time’s Arrow	Arthur C. Clarke	Short story
1950	Forever and the Earth	Ray Bradbury	Short story
1952	A Sound of Thunder	Ray Bradbury	Short story
1954	A Thief in Time	Robert Sheckley	Novella
1955	The End of Eternity	Isaac Asimov	Novel
1955-60	Guardians of Time	Poul Anderson	4 short stories
1962	The Rescuer	Arthur Porges	Short story
1969	Brother Assassin	Fred Saberhagen	Novel
1999	Harry Potter and the Prisoner of Azkaban	J.K. Rowling	Novel

Finally, I will mention my own work, which includes two novels: A Face in Time, which I have mentioned above, and Beyond the Black Hole, where a young drug addict is sent to the past, in the land of the Dakotas.

The same post in Spanish

Thematic Thread on Literature and Cinema: Previous Next

Manuel Alfonseca

Correlation or causality

Francis Galton, Darwin’s cousin, best known for promoting eugenics, invented the mathematical concept of correlation. Since then, many mistakes have been made relating correlation and causality, which sometimes coincide, but can also be completely different.

Two variables are said to be correlated when increases in one resemble increases in the other, and decreases in one resemble decreases in the other. But not all correlations are the same: to distinguish them, Galton devised the correlation coefficient, a number between -1 and 1.

Computational Intelligence and Consciousness

Eduardo César Garrido Merchán

In recent years there have been many advances in artificial intelligence, especially in the field of automatic generation of texts and images that sometimes compete successfully with human productions. In light of this, the media, and even some scientists, have rung the bells announcing that we are on the verge of creating conscious artificial intelligence, which would compete with human beings as our equal. But others believe that this goal, if it were possible (which is not clear), is much further away than some think.

In an article signed by Eduardo César Garrido Merchán and Sara Lumbreras and published in the journal philosophies with the title Can Computational Intelligence Model Phenomenal Consciousness, the authors review Bertrand Russell's analogy, which asserts that consciousness and intelligence are closely correlated. In other words, any entity that possesses consciousness will also possess a high level of intelligence, and vice versa. In a way, this analogy is similar to the Turing Test, which is much better known.

Scientific productivity is declining

String Theory

A team of Chinese and American researchers published on arXiv an article in September 2024 summarizing their study of the development of science and technology over more than two centuries. The study analyzes 213 million scientific articles published between 1800 and 2020, along with 7.6 million patents granted between 1976 and 2020.

The result of this study is the following: while the number of scientific publications has grown exponentially, the knowledge obtained by humanity grows linearly; in other words, the speed of knowledge acquisition is constant and does not grow in the same proportion as the number of publications.

Was Teilhard de Chardin persecuted for defending evolution?

Pierre Teilhard de Chardin

In a previous post I have mentioned some myths related to the persecution of scientists as a result of their scientific ideas, for religious reasons. I mentioned, for example, Giordano Bruno and Miguel Servet, wrongly presented as martyrs of science, when in reality they were persecuted for their religious ideas, not for their scientific activities, which in the case of Bruno were practically non-existent.

The presentation of a recently published video publicizes one of these myths, also widespread: the claim that Teilhard de Chardin was repressed by his Jesuit order for advocating evolution. That this is false can easily be deduced from the fact that Teilhard was able to publish dozens of articles on the evolution of the ancestors of man in scientific and philosophical journals of impact, without being prevented from doing so by his order. One of these journals was Études, edited by the Jesuits. A curious way of repressing him for advocating evolution.

Successes and failures in biological and environmental conservation

Usually, when the media talk about environmental conservation and endangered species, the news they give is almost always negative: Everything is going very badly; there are ever more species at risk of extinction; human activities are corrupting the environment; our planet is in danger of becoming a wasteland incompatible with life… Actually, when we say the highlighted phrase, we are using the trope called synecdoche in the form called macrocosm, that is naming the whole by the part, because it is not the planet that is in danger, but us, human beings, along with many other living beings.

I have just read a book published in 2012, written by Andrew Balmford and entitled Wild hope: on the front lines of conservation success, which tries to emphasize the opposite: not all the news is negative; lately there have been a few successes in the conservation of animal species in danger of extinction, or of environments endangered by human voracity. His analysis of these cases points to shortcomings in environmental conservation processes led by politicians, which sometimes achieve exactly the opposite of what they intended, as I indicated in this blog in a post published almost six years ago, entitled The ecological ignorance of ecologists.

Boethius, time and eternity

Medieval manuscript of
Consolation of Philosophy

1,500 years have passed since the death of Boethius, but the event has gone unnoticed. A century ago, this would not have happened, as history was still being studied. In our times, however, history is despised. And we know what happens to those who despise it, in a phrase attributed to George Santayana: those who do not remember the past are condemned to repeat it.

Anicius Manlius Severinus Boethius was a politician and philosopher of the 5th and 6th centuries, who held important positions in the Ostrogothic kingdom that emerged in Italy shortly after the fall of the Western Roman Empire. In his political activity, Boethius was successively senator, consul and advisor to the Ostrogothic king Theodoric.

Truth versus usefulness

Alvin Plantinga

As I said in a previous post, natural selection is the statistical observation that, in general, individuals better adapted to their environment tend to leave more descendants than those less adapted. It is, therefore, a question of usefulness. A trait that will increase the reproduction of an individual is, in principle, statistically favored by natural selection.

In my popular science book published in Spanish (Biological evolution and cultural evolution in the history of life and man) I mentioned that 

Evolution acts in the same way, both on life and on culture, although its way of acting is adapted to the specific environment on which it is applied (genes, nervous systems or cultural elements). 

Is research on LLM AI slowing down?

John McCarthy

It looks like the fate of the field of computer technology, wrongly called artificial intelligence, is to alternate between excessive optimism and unbridled pessimism. Here is a sketch of the history of this technology:

1. At the Dartmouth College summer school in 1956, the name artificial intelligence was proposed for computer programs that could perform tasks that had traditionally been considered exclusively human, such as playing chess and translating from one human language to another. The attendees, led by John McCarthy, predicted that within ten years these two problems would be solved. They hoped that by 1966 there would be programs capable of beating the world chess champion, and others that could translate perfectly between any two human languages. When these objectives were not achieved so early, research into artificial intelligence stopped. At universities, research topics in this field were frowned upon, because they were thought to have no future.

The kingdom of lies

Abraham Lincoln

 Abraham Lincoln is credited with having said this:

You can deceive some people all the time. You can deceive everybody part of the time. But you can't deceive everybody all the time.

When I was young, if a politician was caught lying, he must resign, because he had deceived the people. This was true back then. Famous politicians who resigned during that time because they had lied included John Profumo, the British minister, in 1963, and Richard Nixon, the US president, in 1974.

This is quite rare now. Today, politicians who resign when they are caught lying are not the rule, but the exception. Many politicians lie whenever they speak, they know that everyone knows that they are lying, but don't care about it. This is an example of the discredit into which the concept of truth has fallen, which was one of the most important criteria in history, not just for politics, but for science and all forms of human thought.

Religious persecution of scientists?

William Harvey

This summer, Jesús Lizcano published an article in El Imparcial entitled. A memory for the scientists persecuted in history (my translation). He classifies the persecuted scientists into three groups: a) persecuted for political reasons; b) persecuted for religious reasons; and c) persecuted for reasons of sexual orientation. Here I am going to refer to those in the second group, which I find debatable.

Of course, among the eleven scientists persecuted for religious reasons, according to Lizcano, Hypatia and Galileo could not be missing. They are mentioned once and again, often with obvious exaggerations, as shown by the fact that many people believe that Galileo was burned alive by the Inquisition, when in fact he was sentenced to house arrest, softened over time. But here I am going to talk about the other nine mentioned in the article.

Information paradoxes

Woody Allen

As I have mentioned before, time travel, if it were possible, would cause many paradoxes. In a previous post I mentioned the paradox of unsourced information, which can be summarized thus:

A time traveler who lives in time 3 knows that a person A said or did something at time 2, prior to time 3. 

The traveler goes back from time 3 to time 1, prior to time 2, where he meets A. 

While they are together, the traveler suggests person A the idea of ​​doing or saying what he knows that person will do or say in the future, which has not yet taken place. 

Whose idea was it originally? Not the traveler’s, because he learned it from the history of person A at time 3. Not from person A, because the traveler suggested the idea to person A at time 1. 

The information in question has come out of nowhere, without anyone having thought it out.

The following diagram explains it.

Mistakes regarding natural selection

Charles Darwin

Since Charles Darwin coined this term, and included it in the title of his famous book, published in 1859, the term natural selection has been poorly understood, especially by non-specialists. Let’s review a few of the most frequent mistakes:

• Natural selection is a force that acts on living beings to cause evolution. This is not true. Natural selection is not a force, nor an object, nor an interaction, nor a phenomenon. It is simply a statistical observation. What is observed is the fact that, in general, individuals better adapted to their environment tend to leave more descendants than those less adapted. Nothing else. It is, therefore, a matter of common sense, not the result of the external action of a mysterious force.

Longevity and aging

Almost eight years ago I wrote a post on this topic in this blog, which contained a figure that I built starting from data provided by the Spanish Institute of Statistics, which showed mortality data for Spain in three different years: 1900, 1991 and 2013. The three curves in the figure represent the percentage of people who have reached a certain age and will die during the next year. I’m showing here an equivalent figure, with updated data that correspond to the years 1900, 1991 and 2022, as we now have more recent data.

As I said then, the figure shows that medical advances have reduced mortality, especially at the beginning and the end of life, but their effects are little noticeable for people between 20 and 40 years old. The mortality curve, which in 1900 was U-shaped, is approaching an inverted L, with a very low rate for almost all of life and a fairly abrupt rise after age 80.

Singularities

Hal 9000, from the film
2001, a space odyssey

A singularity is a mathematical concept applied to a function of a variable that reaches an infinite value for one or several finite values of its independent variable.

For example, the function y=1/x presents a singularity for x=0, since it is often said that 1 divided by zero is equal to infinity.

What happens with cholesterol?

Cholesterol is an essential lipid, used to build the membrane of many of our cells. In addition, various steroids, bile acids and vitamin D are synthesized from cholesterol within the body. High cholesterol increases the chances of suffering from heart attacks and strokes. On the other hand, too low cholesterol is associated with depression that can even lead to suicide.

When someone says: I have had an analysis and it turns out that I have cholesterol, we should answer: If you didn’t have cholesterol, you’d be dead. What you have is high cholesterol.

Is science taught correctly?

According to many evaluations, education at the elementary and secondary levels is faulty. Every year, students arrive at the university knowing less, which makes it necessary to lower the level at the university or use desperate remedies, such as the implementation of level zero courses.

On the other hand, textbook publishers sometimes launch a race. Secondary education is supposed to provide students with general, non-specialized training. However, in some subjects, such as chemistry and biology, students may be made to learn questions or solve problems that should be encountered in college, several years later. It seems a contradiction that they are forced to learn more, but actually get out knowing less.

Inventing worlds

Isaac Newton

Physicists seem to have lost touch with reality. Instead of figuring out how the universe works, they dedicate themselves to designing possible universes, an activity that possibly they find pleasurable, but which doesn't seem very practical. The worst thing is that they often insist that their imaginary universes are real, putting speculations above experimentation and transgressing one of the fundamental principles of the scientific method: theories must adapt to facts, not the other way around.

One of the weak points of modern physics is the difficulty of explaining the passage of time. Since Newton’s theory, but especially with Einstein’s relativity, our physicists have not been able to deal with time. This happens, despite the fact that other conceptions of physics, such as thermodynamics and quantum mechanics, require unidirectional time: quantum superposition and collapse make no sense except with the hypothesis of irreversible time.

A few trivia about the fine structure constant

Clifford Pickover

In a post I published in this blog over three years ago, I talked about the fine structure constant and some of its physical peculiarities. In this post I am going to talk about some of its mathematical peculiarities. I have taken them from a book I have mentioned on other occasions: A Passion for Mathematics, by Clifford A. Pickover.

As we know, the most exact value of this constant is this:

α = 1/137.035999206

Pickover points out that Eric W. Weisstein, in his World of Physics website, offers two mathematical approximations incredibly close to this value:

Black holes or gravastars?

As I explained in a previous post, our two fundamental physical theories, general relativity and quantum mechanics, predict infinities that physicists don’t like. General relativity does this in gravitational singularities: the Big Bang and black holes. Quantum mechanics, in vacuum energy and the quantities that must be renormalized in quantum field theory.

Until a little time ago, the theory of black holes, formulated by Subrahmanyan Chandrasekhar in 1930, stated the following: when a star 30 to 70 times more massive than the sun undergoes a supernova explosion, it expels most of its mass, but a part of it (at least 3.8 times more massive than the sun) collapses to such a point that it occupies zero volume, and so it will have an infinite density.

The dream of antigravity

Man has always wished to be able to fly. Seeing how birds do it and not being able to do it has obsessed him, to the point of causing quite a few accidents. It is a craving that even very young children know. Some mishaps caused by the viewing of the movie Superman at the end of the seventies may be proof.

At the end of the 19th century, two fundamental interactions were known: electromagnetic and gravitational. In one respect, both are quite different. Electrically charged bodies can have a positive or a negative charge. A positive and a negative charge attract each other; two positive or two negative charges repel each other. Likewise, magnetic bodies have two ends with magnetism of a different type, north and south. If we bring two magnets together, the north end of one and the south end of the other attract each other; ends of the same type repel each other.

Does science explain everything?

William Shakespeare

Scientism is the philosophical theory that affirms that science is the only valid source of human knowledge. Taken literally, this statement sometimes leads to absurd conclusions. Perhaps the following case is an example of scientism. I’ve taken it from a recent article by Joseph Pearce entitled Shakespeare and Science.

Kathryn Harkup, British doctor in chemical sciences and science communicator, has published several books analyzing various literary works from the point of view of science. I don’t know if Harkup is a case of scientism, but her emphasis on science makes me think that perhaps she is. She has recently published a book titled Death by Shakespeare, where she criticizes how Shakespeare presents death in his plays, based on what she believes science modern knows about death. Pearce highlights two examples, which show some of the absurd conclusions caused by basing only on science.