The Kingdoms of Cladistics

In the previous post, I discussed cladistics, the new way of classifying living things based on their position in the tree of life, and mentioned some of the difficulties that arise when trying to adapt the previous classification system, based on the taxonomic tree and Linnaeus's classic categories—kingdom, phylum, class, order, family, genus, and species—to cladistics.

There are more difficulties. For example, let's consider the concept of kingdom, Linnaeus's highest taxonomic category. Traditionally, living things were divided into two kingdoms: animals and plants. These two kingdoms were clearly separate, with very different characteristics. Thus, animals were defined as organic beings that live, feel, and move by their own impulse, while the plant kingdom were beings that live but do not feel and do not move. It was acknowledged that these definitions were imperfect, because there were exceptions, such as sponges, which barely move but are animals, and some plants, like mimosas, which seem to sense certain stimuli and move in response.

Cladistics: A new classification of living beings

Tree of life
https://evogeneao.s3.amazonaws.com/
images/content/es/tree-of-life_2000.png

In 1735, the Swedish naturalist Carl von Linné (Linnaeus) created the binomial system of biological nomenclature still in use today, and a classification system for living things that is becoming obsolete. This system used at first seven successive categories: kingdom, phylum, class, order, family, genus, and species. The last two categories are used to name the species. Thus, according to Linnaeus's classification, the human species belongs to the animal kingdom, the phylum Chordata, the class Mammalia, the order Primates, the family Hominidae, the genus Homo, and the species sapiens. Its scientific name, according to Linnaeus's binomial system, is therefore Homo sapiens.

Time Travel and Christ’s Crucifixion

Christ crucified, wood carving
by Manuel Alfonseca Santana

If time travel were possible, the greatest incentive for travelers would be to witness firsthand famous events of the past, such as the assassination of Julius Caesar and many others. The fact that we have no record of the presence of strangers in any of these cases is a significant argument against the feasibility of time travel.

There is no doubt that one of these events, perhaps the most famous of all, would be the Crucifixion of Christ. If time travel were possible, there should have been an avalanche of visitors from future times at Golgotha ​​to witness the most important event in the history of humankind.

In fact, this idea has been used in science fiction literature. In a novella titled There Will Be Time, Poul Anderson has his protagonist travel to Jerusalem on the day of the Crucifixion to witness Christ's death. Upon arriving, he discovers a large crowd, almost all of whom are time travelers.