Ant colonies, real and virtual

Formica fusca

Ants, hymenoptera related to wasps, are social insects. An anthill or ant colony can contain, from a few dozen individuals, to over half a million. The number of castes varies, depending on the species, between three (fertile males and females, sterile female workers) and over twenty. The feeding a larva receives decides the caste to which it will belong.

Strange forms of parasitism have arisen among ants, as in Amazons ants (Polyergus), whose workers specialize in fighting and starve in the presence of food, unless a worker of Formica fusca feeds them. To seize these auxiliaries, the Amazons attack the nests of Formica fusca, kill their queen and enslave the workers. In extreme cases, such as ants of the Anergates genus, the queen invades a nest of Tetramorium, supplants its queen, and fed by the workers of the other species, produces eggs that become queens and males, but no workers, which are not needed.

Evolution in social insects probably reached the highest levels of instinctive complexity that can be achieved with a nervous system as limited as that of arthropods. In the tens of million years since the origin of these societies, evolution has introduced secondary changes, which have led to great diversity: there are more than three thousand species of ants, but there seems to have been no progress in their social structure. They are highly successful animals, very abundant, and spread throughout the world, but stagnant.

Mathematics of the pandemic

The May issue of the Spanish magazine on popular science Investigación y Ciencia, associated to Scientific American, contains an article authored by Bartolo Luque, Fernando Ballesteros and Octavio Miramontes, in which they apply to the current pandemic a mathematical model that dates back over a century. This model describes the first phase of the pandemic, the exponential rise of the first part of the logistics curve that I referred to in a previous post in this blog, and makes it possible to compare the evolution of the disease in various countries, depending on the virus containment measures that have been taken in each of them. It could also serve to explain why Spain has become the country with the most cases in Europe and with the most deaths per 100,000 inhabitants in the world.

The evolution of the pandemic in Spain

Logistic curve

Using the data provided every day by the Spanish Ministry of Health, about the number of new cases affected by the pandemic each day, and the number of deaths, we have carried out the following analysis:

1. We have manipulated slightly the real data to take into account the weekend effect, pointed out by the minister, which consists in the fact that the figures for new cases for March 28, 29 and 30 are not faithful to the reality, because fewer cases are declared on the weekend (we are used to waiting until Monday to do it), and then, on Monday, all the missing cases get accumulated. As by then the curve had flattened, what we’ve done is replacing the data about new cases for those three days by the average of the three, thus redistributing the Monday excess between Saturday and Sunday. The following weekend, April 4, 5 and 6, we made the same correction. The attached figure represents the number of new cases for each day (red curve) and the number of deaths (green curve). The numbers in the abscissa of the figure represent days counted from the beginning of the data. Day 1 corresponds to March 3. Day 36 is April 7, the last day about which there were data when this post was published.

The heralded pandemic

SARS-CoV-2

The November 2005 issue of Scientific American published an article signed by W. Wayt Gibbs and Christine Soares titled Preparing for a Pandemic. The article had the following subtitle-summary:

One day a highly contagious and lethal strain of influenza will sweep across all humanity, claiming millions of lives. It may arrive in months or not for years--but the next pandemic is inevitable. Are we ready?

Fourteen years later, the pandemic is here, although the authors were mistaken in one detail: they thought it would be caused by the influenza virus, but it was actually a coronavirus. These viruses belong to two different families:

Travelling to the past?

S.Augustin, by Louis Comfort Tiffany
Lightner Museum

In his Confessions (Book XI, chapter 14), St. Augustine wrote these words, still valid today:

What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know.

In the current situation of our scientific and philosophical knowledge, we still don’t know what time is.

·         For classical philosophy and Newton’s science, time is a property of the universe. Therefore, time would be absolute.

·         For Kant, time is an a priori form of human sensibility (i.e. a kind of mental container to which our sensory experiences adapt).

·         For Einstein, time is relative to the state of repose or movement of each physical object. There is, therefore, no absolute time.

·         For the standard cosmological theory, there is the possibility to define an absolute cosmic time for every physical object, measuring the time distance since the Big Bang to the present.

·         For the A theory of time (using J. McTaggart’s terminology) the flow of time is part of reality. The past no longer exists. The future does not yet exist. There is only the present. If the A theory is correct, travel to the past is impossible, because you cannot travel to what does not exist.

·         For the B theory of time, the flow of time is an illusion. Past, present and future exist simultaneously, but for each of us the past is no longer directly accessible, and the future is not yet accessible. Einstein adopted the B philosophy of time. In a condolence letter written to someone who had lost a beloved person, he wrote the following:

The distinction between past, present and future is only a stubbornly persistent illusion.

We are not living in a simulation: a note on Nick Bostrom’s proposal

Simulation of the collision of two galaxies

In a paper published in 2003 [1] Nick Bostrom proposed the following reasoning:

A technologically mature “posthuman” civilization would have enormous computing power. Based on this empirical fact, the simulation argument shows that at least one of the following propositions is true:

(1)   The fraction of human-level civilizations that reach a posthuman stage is very close to zero;

(2)   The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;

(3)   The fraction of all people with our kind of experiences that are living in a simulation is very close to one.