Turris Babel

In Book One, Kircher resumed the account he had begun in Arca Noë of the generations that came after Noah.^[1]: 18 He addressed the question of how, just 275 years after the Flood, Noah's great-grandson Nimrod could command such a large number of people to build the Tower. He demonstrated that, assuming each of Noah's sons had a son and a daughter each year, and each of them in turn began procreating at the age of thirty, the world population would have been 24,328,000,000 by Nimrod's time.^[2]: 174 In fact, Kircher's mathematics were flawed, and by his own method of reckoning the correct total would have been 233,280,000.^[3]: 237

In Book Two, Kircher devoted much care to demonstrating that Nimrod's building project to build a tower to touch the heavens was physically impossible to achieve, and would have been disastrous for the planet Earth if it had been achieved. Kircher explained that the distance from the Earth to the lowest celestial sphere, that of the Moon, was twenty-five earth diameters. There were not enough building materials in the world to construct a tower so high, and if it had been built it would have pulled the entire planet over out of its equilibrium at the centre of the universe, causing darkness and extreme climate change in many parts of the world.^[3]: 237

In addition to this, Kircher offered an illustrated survey of the wonders of the ancient world, including the pyramids of Egypt, the labyrinth of Crete and the colossus of Rhodes.^{[3]: 238 [1]: 18 [4]: 110–118}

The third book of Turris Babel dealt with linguistics.^[1]: 18 Kircher affirmed that before the Flood there had been no division of nations or languages.^[2]: 178 His theory of language was that the original human speech of the Garden of Eden was perfect, in that words corresponded exactly with the objects for which they stood. This he called the Lingua Humana, which he declared was a form of early Hebrew language. This had been spoken by Noah and his descendants up to the time of the Confusion of Tongues, when God punished the pride of mankind by dividing them into speakers of many languages.^[5]: 7–8

Kircher did not support the view that God had punished each of the builders of the Tower of Babel by giving them their own language to speak. Rather, he argued that people were divided by family, with Shem and his descendants continuing to speak Hebrew, and his brothers adopting respectively the Greek language, the Latin language, the Teutonic language, and the Slavic language.^[6]: 35 As people dispersed from Babel, the five basic languages spoken by different branches of Noah's family continued to diversify, leading to the establishment of seventy-two mother languages, from which all languages in the modern world were descended.^[7]

As well as discussing spoken language, Kircher also considered writing systems, and showed how a common origin could be found for the Hebrew alphabet and the Latin alphabet. He argued however that the Egyptian hieroglyphs and the Chinese characters did not share this common origin.^[3]: 238

Kircher saw the Confusion of Tongues as being the start of a lapse from the true religion into various forms of idolatry.^[3]: 238 He argued that the deities of different ancient religions were all derived from veneration of the Sun and Moon. He also maintained that variations in human skin colour arose from differences in climate in the places to which people dispersed.^[6]: 35