Marin Mersenne sIn existographies, Marin Mersenne (1588-1648) (CR:18) was French theologian, philosopher, mathematician, and music theorist, a "Cartesian defender" (Conlon, 2011), noted for []

Mersenne was friends with Galileo, Thomas Hobbes, Rene Descartes, and Pierre Gassendi.

In the 1620s, Mersenne, in some book, which contained a “catalog of atheists”, listing: Bonaventure des Periers (c.1500-1544) (Ѻ), Pierre Charron, Niccolo Machiavelli, Lucilio Vanini, and Giordano Bruno, among other, claimed that there were 50,000 atheists living in Paris (population: 400,000), a 12.5 percent atheism population. [1]

In 1625, Mersenne, in his Verite des Sciences, presented a dialogue, wherein Christian philosopher, a sceptic, and an alchemist discus the a proposal to open an alchemical college; this was said to be thematic in tone in style to Robert Boyle’s later Sceptical Chymist. [4]

In c.1647, Mersenne was the one who told Blaise Pascal about the Torricelli vacuum (1643). [2]

Quotes | On
The following are quotes on Mersenne:

“As to the history of the quicksilver experiment [Torricelli vacuum], your reverence may know that the many wells of Florence which are cleaned out every year by means of siphons ‘by attraction’, gave signor Galileo occasion to observe the height of such attraction, which was always the same about 18 ells in that Tuscan measure; and so in every siphon or cylinder (as we like to say) however wide or narrow. From this had their origin his speculations about that matter, which were pout into his work on the resistance of solids. Afterwards, signor Gaspar Berti, here in Rome, made a led siphon which rose to about 22 ells from his courtyard to a room.”
— Raffaello Magiotti (1848), “Letter to Marin Mersenne”, May 25 [3]

“If we take the mathematics, and those mixed sciences to which they are applicable, it will be universally admitted that their most successful cultivators in France during the seventeenth century were Descartes, Pascal, Fermat, Gassendi, and Mersenne. Fermat, among these, was one of the most profound thinkers of the seventeenth century, particularly as a geometrician, in which respect he was second only to Descartes. The most important steps are those concerning the geometry of infinites, applied to the ordinates and tangents of curves; which he completed in or before 1636.”
— Henry Buckle (1856), History of Civilization, Volume One (pg. 499-50)

“In contrast to the Cartesian caution, in Germany — where orthodox Cartesianism never gained a foothold — several prominent thinkers embraced the belief that the fixed stars were surrounded by planets and spread throughout an infinite universe. The Ecstatic Celestial Journey (Iter exstaticum coeleste), 1656, by the Jesuit Athanasius Kircher explicitly characterized the fixed stars as suns with encircling planets, although it denied inhabitants even to the planets of our solar system and to the moon. And Otto Guericke, famous for the ‘Magdeburg experiments’ proving the existence of a vacuum, devoted a section of his Experimenta Nova (1672) to an examination and endorsement of Kircher's view of other planetary systems. Von Guericke also noted the possibility of an inhabited moon and planets, and emphasized (following Galileo) that any inhabitants would not be men, but rather diverse creatures beyond all our imaginings. But von Guericke denied Descartes's equation of extension and matter, and instead traced his ideas to Galileo, Kepler, Antonius de Rheita (Ѻ), Mersenne, Bruno, and Nicholas of Cusa.”
— Steven Dick (1984), Plurality of Worlds (pg. 116)

“The center of interest in the vacuum questions in 1645 to 1651 was France, where Mersenne reported on the Italian work, and where natural philosophers such as Pascal, Petit, Roberval, and Pecquet all gave their views and experimented with the Torricellian apparatus.”
Steven Shapin (1985), Leviathan and the Air Pump (pg. 41)

Quotes | By
The following are quotes by Mersenne:

“To us his incredible genius seems almost miraculous.”
— Marin Mersenne (c.1647), comment on Galileo (or Torricelli) (Ѻ)

1. Hecht, Jennifer M. (2003). Doubt: A History: The Great Doubters and Their Legacy of Innovation from Socrates and Jesus to Thomas (pg. 309). HarperOne.
2. Conlon, Thomas. (2011). Thinking About Nothing: Otto von Guericke and the Magdeburg Experiments on the Vacuum (pg. 44). Saint Austin Press/LuLu.
3. Middleton, William E. (1964). The History of the Barometer (pg. 16) (Amz). Publisher.
4. Shapin, Steven; Schaffer, Simon. (1985). Leviathan and the Air Pump: Hobbes, Boyle, and the Experimental Life (pg. 71). Princeton, 2011.

Further reading
● Mersenne, Marin. (c.1640). The Impiety of Deists, Atheists, and Libertines of These Times. Publisher.

External links
Marin Mersenne – Wikipedia.

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