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It’s the first Friday of the month, time for another post on the history of atom theory by physics professor (and my dad) Dean Zollman. In this installment, we’re in the 17th century, and a French clergyman seeks to reconcile the scientific theory of ancient Roman philosophers with Catholic teachings. Today is also the last day of the Summer Banquet blog hop, which includes my contribution, Dandelions for Dinner. – Kim

By Dean Zollman

Dean ZollmanIn his book The Atom in the History of Human Thought, Bernard Pullman separates the 17th century development of ideas about atoms by religion. He notes that Catholics, primarily in France and Italy, wanted control over new ideas while Protestants, primarily in England, were somewhat indifferent toward thoughts about atoms. I will follow Pullman’s line of thought and spend a couple of posts looking at some Catholic 17th century views first.

As I discussed in the previous post, the concepts of atoms as expressed by Democritus, Epicurus, and Lucretius were available, primarily through copies of ancient manuscripts. However, these ideas were mostly rejected in favor of the philosophy and science of Aristotle. Recall that Aristotle’s physics could not include a void and thus he rejected the ideas of atoms. Further, Aristotle’s philosophy had become integrated into Catholic philosophy by this time.

Pierre Gassendi (1592-1655), a French clergyman, set out to change this state of affairs. He wanted to bring together medieval religion, humanism as expressed in the Renaissance, and the science of his day. To do this, he set a goal of making Epicurean thought as acceptable as that of Aristotle.

Pierre Gassendi

Pierre Gassendi in a 1750 engraving by Michel Odieuvre (public domain image via Wikimedia Commons)

Gassendi’s writing on philosophy and science are extensive, so I will only touch on a few points here. Foremost, he sought, whenever possible, empirical evidence for his scientific ideas. For example, Galileo has concluded logically that a ball dropped from the mast of a moving ship would fall so that it landed on the ship next to the mast. Gassendi actually had the experiment conducted. Logic alone was not sufficient for him. When it came to atoms, he needed to rely on indirect evidence because direct observation was not possible. As we will see in the next paragraph, he sometimes needed to fudge a little on this point.

Gassendi’s atomism was extensive. To bring these ideas into acceptability for the Church, an important part was allowing God and atoms to both have a place in his worldview. The ancient Greeks stated that atoms were eternal. Creation was not part of their system. Gassendi rejected this idea even though he would be hard pressed for empirical evidence. In his worldview atoms were created by God. Even more, God provided atoms with their motions. Thus, God preordained what would happen because future events would be determined by the motions and collisions of these atoms.

Another issue was the soul. The ancients had concluded that souls as well as bodies were made of atoms. Gassendi’s view was maybe that’s OK for cats and broccoli but not for humans. Human souls had a spiritual component which was created by God.

With topics such as Creation and souls covered, Gassendi could build an atomism that used the ancient Greek’s ideas as a foundation. His atoms were real objects not mathematical points. They were in constant motion in all directions. They had a variety of properties and even combined to form molecules. Overall, Gassendi allowed atoms to be acceptable and not inconsistent with the faith of his day. In Pullman’s words, “From a historical perspective, it could be said that Gassendi added God to atoms, although he probably would have preferred to be seen as having returned atoms to God.” And, atoms were returned to the scientific thought of the 17th century.

Gassendi was almost 30 years younger than Galileo. Of course, Galileo had his own problems with the Church. One (and as far as I can determine only one) historian believes that these problems involved atoms as well as the solar system. We will look at that issue next time.


What Are Things Made of? Depends on When You Ask.

Ancient Greeks Were the First to Hypothesize Atoms

The Poetry of Atoms

Atom Theory in Ancient India

Religion, Science Clashed over Atoms

Medieval Arabic Scholarship Might Have Preserved Scientific Knowledge

Rediscovering a Roman Poet – and Atom Theory – Centuries Later

Dean Zollman is university distinguished professor of physics at Kansas State University where he has been a faculty member for more than 40 years. During his career he has received three major awards—the National Science Foundation Director’s Award for Distinguished Teacher Scholars (2004), the Carnegie Foundation for the Advancement of Teaching Doctoral University Professor of the Year (1996), and American Association of Physics Teachers’ Robert A. Millikan Medal (1995). His present research concentrates on the teaching and learning of physics and on science teacher preparation.