Blaise Pascal

Science & Dogma

For several hundred years, European Christianity organized its thought system around the logic and science of Aristotle, who lived more than three hundred years before Jesus. Aristotle’s amazing output and powerful methods of reasoning provided the Christian church a framework for interpretation and application of abstract theological ideas. Consequently, Aristotle’s works had an almost sacred status. In many instances, to challenge Aristotle’s claims about the physical workings of the world was tantamount to denying Christian orthodoxy, which was heresy. Aristotle never intended for his thinking to be taken as dogma, but generations of European scholastics did exactly that.

Rene Descartes (1596-1650) and Galileo Galilei (1564-1642) were among the first to succeed in seriously challenging the dogmatic grip on scientific thought. The struggle between the traditional scholastic dogmatists and the new scientific experimentalists was in full force during Pascal’s lifetime. That he was able to find points of common ground between faith and science is another testament to his brilliant insight.

Pascal’s foremost contribution to science is his experimental demonstration that atmospheric pressure varies with elevation and the resulting conclusion that a vacuum may exist in conformity with natural law. In 1643 an Italian mathematician, Evangelista Torricelli, created a barometer made from a glass tube sealed at one end and filled with mercury, held upside down in a bowl of mercury. Some of the mercury remained suspended in the tube. This experiment led to two important questions:
(1) what holds up the suspended mercury?
(2) what remains in the empty portion of the sealed tube?

These questions were particularly perplexing because Aristotle had stated that “nature abhors a vacuum.” In book IV of his Physics, Aristotle gives numerous arguments against the possibility of a vacuum or void. Some of his arguments are compelling and he notes that several other philosophers do accept the existence of a void (vacuum). So, plainly for Aristotle matters such as this were matters of debate and his arguments remain open to revision. He would have welcomed questioning and experimentation. In the hands of the orthodox Church, however, the written word of accepted authority was the final word. This was so for the scriptures, Papal edicts, and officially accepted texts such as Aristotle.

Pascal continued Torricelli’s experiments and added an ingenious variable; he took the barometer apparatus to the top of a mountain and compared measurements taken at different elevations. Since the pressure of the atmosphere decreases with height, Pascal deduced that a vacuum existed above the atmosphere. The results supported the claim that air pressure was the major force involved in the suspension of the mercury in the tube. From this work Pascal also worked out the mechanics of syphons, as functions of air pressure and liquid volume. Modern science was taking shape in this synthesis of theory (abstract thought) and practice (experimental observation).

Next - Learn about Pascal's mathematical work

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