Background
Gassendi was born on on January 22, 1592 at Champtercier, near Digne, in France to Antoine Gassend and Françoise Fabry.
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Astronomer mathematician philosopher priest
Gassendi was born on on January 22, 1592 at Champtercier, near Digne, in France to Antoine Gassend and Françoise Fabry.
Pierre entered the University of Aix-en-Provence, where he studied philosophy under Philibert Fesaye, O. Carm. at the Collège Royale de Bourbon (the Faculty of Arts of the University of Aix).
Gassendi is an Italianized form of Gassend used in Provence.
He took minor orders in 1612, became a canon of Digne Cathedral in 1616 and professor of philosophy at Aix in the same year. In 1624, he published, at Grenoble, a series of essays entitled Exercitationes paradoxicae adversus Aristoteleos, in which he declared that, although obliged by the nature of his post to teach the philosophy of Aristotle, he had always taken care to point out the weaknesses of Aristotle's system.
Instead of continuing his polemic against the Schoolmen - a sort of skirmishing likely to make enemies for him in the Church - he turned to Epicurus and began, in 1626, to plan a work on his life, morals, and teaching.
He was convinced that Epicurus' teaching could be made to conform with the current theology, concerning which he avoided committing himself.
In 1632 he published observations on the transit of Venus and in 1641 demonstrated experimentally the truth of Galileo's theory of falling bodies.
His inaugural lecture (Institutio astronomica; 1647), while not openly declaring for Galileo, shows sympathy for him.
In 1648, suffering from tuberculosis, Gassendi left for Provence.
A complete edition of his works appeared in 1658.
The logic is a method of enquiry, mainly inductive, but it attempts a balance between experience and reason.
The physics describes a world composed of atoms and void, created by God, whose existence is shown by the harmony and order of the world.
God is the first cause; all the second causes are motion, and motion is a property of the atoms.
The most mobile of the atoms compose the souls of animals capable of sensation and "sensitive reason. "
He was the main rival of Descartes as an exponent of the "new philosophy. "
He influenced Robert Boyle and John Locke and was greatly esteemed by Sir Isaac Newton.
As part of his promotion of empirical methods and his anti-Aristotelian and anti-Cartesian views, Pierre Gassendi was responsible for a number of scientific 'firsts':
He explained parhelia in 1629 as due to ice crystals.
In 1631, Gassendi became the first person to observe the transit of a planet across the Sun, viewing the transit of Mercury that Kepler had predicted. In December of the same year, he watched for the transit of Venus, but this event occurred when it was night time in Paris.
Use of camera obscura to gauge the apparent diameter of the moon.
Dropping stone from mast of ship (in De motu) conserves horizontal momentum, removing an objection to the rotation of the earth.
Measurement of speed of sound (to about 25% accuracy), showing that it is invariant of pitch.
Satisfactory interpretation of Pascal's Puy-de-Dôme experiment with a barometer in the late 1640s; this suggested a created vacuum is possible.
In addition to this he did work on determining longitude via eclipses of the moon and on improving the Rudolphine Tables. He addressed the issue of free fall in De motu (1642) and De proportione qua gravia decidentia accelerantur (1646).
