1. 1 Pierre Gassendi and the Void ISIH Conference Ann T. Orlando Weston Jesuit School of Theology 18 April 2007

2. 2 Background on Pierre Gassendi Born in Champtercier, France 1592 died 1655 in Paris Born in Champtercier, France 1592 died 1655 in Paris One of the most famous physicists of his day One of the most famous physicists of his day Some beliefs out of step with other natural philosophers Some beliefs out of step with other natural philosophers

3. 3 Gassendi’s Intellectual Model Techniques of empiricists and humanists Techniques of empiricists and humanists Probabilistic epistemology Probabilistic epistemology Relationship between physics and mathematics Relationship between physics and mathematics Words as best descriptor of nature Words as best descriptor of nature

4. 4 Toward a Systematic Philosophy Epicureanism as a philosophical framework Epicureanism as a philosophical framework Challenge of reconciling Epicureanism with seventeenth-century Christianity (Catholicism) Challenge of reconciling Epicureanism with seventeenth-century Christianity (Catholicism) Atheism, mortality of soul, ethics based on pleasure Atheism, mortality of soul, ethics based on pleasure Eternity of cosmos, existence of void, atomic structure of matter Eternity of cosmos, existence of void, atomic structure of matter Little previous work examined details of Gassendi’s efforts to reconcile Epicureanism and Christianity Little previous work examined details of Gassendi’s efforts to reconcile Epicureanism and Christianity

5. 5 Rehabilitating Epicureanism Gassendi had to refute damaging ad hominem attacks against Epicurus Gassendi had to refute damaging ad hominem attacks against Epicurus He makes God the “author” of most objectionable Epicurean tenets He makes God the “author” of most objectionable Epicurean tenets

6. 6 Gassendi and Christian Classics Tried to reconcile physics with Bible, primarily through commentaries on Genesis Tried to reconcile physics with Bible, primarily through commentaries on Genesis If later Christian philosophers could ‘rehabilitate’ Aristotle, Gassendi should be allowed to rehabilitate Epicurus: If later Christian philosophers could ‘rehabilitate’ Aristotle, Gassendi should be allowed to rehabilitate Epicurus: “The early Church Fathers were particularly opposed to Aristotle and his philosophy, and they displayed extreme animosity against the followers of Aristotle. But when some philosophers were converted to the faith, they began to set aside the more serious errors of Aristotle. What remained of Aristotelian philosophy was then accommodated to religion so successfully that it was no longer suspect and finally became the handmaid ministering to religion. Therefore I say, just as it was possible in the case of Aristotelian philosophy, which is now taught publicly, so it is possible with other philosophies such as the Stoic and Epicurean. All of them have much that is of value and worthy of being learned once the errors are eliminated and refuted in the same way as the very grave errors of Aristotle were refuted.” Syntagma Philosophicum, Opera Omnia 1:5. “The early Church Fathers were particularly opposed to Aristotle and his philosophy, and they displayed extreme animosity against the followers of Aristotle. But when some philosophers were converted to the faith, they began to set aside the more serious errors of Aristotle. What remained of Aristotelian philosophy was then accommodated to religion so successfully that it was no longer suspect and finally became the handmaid ministering to religion. Therefore I say, just as it was possible in the case of Aristotelian philosophy, which is now taught publicly, so it is possible with other philosophies such as the Stoic and Epicurean. All of them have much that is of value and worthy of being learned once the errors are eliminated and refuted in the same way as the very grave errors of Aristotle were refuted.” Syntagma Philosophicum, Opera Omnia 1:5.

7. 7 The Problem with a Void Epicurus had suggested that all tangible things are composed of atoms which move randomly through a void Epicurus had suggested that all tangible things are composed of atoms which move randomly through a void Aristotle had been strongly opposed to the concept of atomic motion and a void in nature Aristotle had been strongly opposed to the concept of atomic motion and a void in nature Another important Aristotelian argument against the void was based on his definition of motion Another important Aristotelian argument against the void was based on his definition of motion Aristotelian physics dominated medieval physics Aristotelian physics dominated medieval physics Condemnations of 1277 Condemnations of 1277

8. 8 Gassendi’s Evidence for a Void Empirical Evidence Empirical Evidence Chemical Chemical Barometric Barometric Dynamic Dynamic Historical Christian Evidence Historical Christian Evidence Angels Angels Nemesius Nemesius Irenaeus Irenaeus

9. 9 Implications of a Void: Space and Time Not the same things as corporeal entities Not the same things as corporeal entities Infinite and Eternal Infinite and Eternal Exist Independently of God Exist Independently of God God creates in space and time God creates in space and time

10. 10 Gassendi’s Evidence For the Nature of Space and Time Nemesius Nemesius Augustine Augustine Scripture Scripture Gelasius Gelasius

11. 11 Impact of Gassendi’s Understanding Perceptive, even revolutionary, insight into existence of void, space and time Perceptive, even revolutionary, insight into existence of void, space and time Important distinction between how space and time are measured and what they are Important distinction between how space and time are measured and what they are Influenced Newton’s understanding of space Influenced Newton’s understanding of space

12. 12 Conclusion Later physicists confirm Gassendi’s understanding of the void Later physicists confirm Gassendi’s understanding of the void Intellectual model that embraced both empiricism and humanism in natural philosophy was quickly eclipsed Intellectual model that embraced both empiricism and humanism in natural philosophy was quickly eclipsed Gassendi’s emphasis on words replaced by mathematics as the best way to describe nature Gassendi’s emphasis on words replaced by mathematics as the best way to describe nature