# Alex Peek blog

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Monday, April 26, 2021

## Christiaan Huygens and certainty

Photo source: Wikimedia Commons, Caspar Netscher

Christiaan Huygens (1629-1695) was a Dutch mathematician best known for his contributions to optics, astronomy and pendulum clocks. Professor Joella Yoder said,

"[*Horologium Oscillatorium*] is the first modern treatise in which a physical problem is idealized by a set of parameters then analyzed mathematically. It is one of the seminal works of applied mathematics." (Christiaan Huygens: Book on the Pendulum Clock)

The rest of this post is some quotes from Huygens.

### Certainty

"I believe that we do not know anything for certain, but everything probably. " (Letter to Pierre Perrault, 1673)

"There are many degrees of probable, some nearer truth than others, in the determining of which lies the chief exercise of our judgement." (Cosmotheoros, 1695-1698)

"One finds in this subject a kind of demonstration which does not carry with it so high a degree of certainty as that employed in geometry; and which differs distinctly from the method employed by geometers in that they prove their propositions by well-established and incontrovertible principles, while here principles are tested by inferences which are derivable from them." (Treatise on Light, 1690)