What nationality was the man who determined that light has a finite speed?
Rømer's determination of the speed of light Rømer's determination of the speed of light was the demonstration in 1676 that light has a finite speed, and so does not travel instantaneously. The discovery is usually attributed to Danish astronomer Ole Rømer (1644–1710), who was working at the Royal Observatory in Paris at the time.
Laplace's demon In the history of science, Laplace's demon was the first published articulation of causal or scientific determinism by Pierre-Simon Laplace in 1814. According to determinism, if someone (the Demon) knows the precise location and momentum of every atom in the universe, their past and future values for any given time are entailed; they can be calculated from the laws of classical mechanics.