Experimentum crucis

This experiment settled the question: Was there some natural resistance to the creation of an apparently empty space at the top of the tube, or was the height of the mercury determined solely by the weight of the air?

[1] In his Philosophiæ Naturalis Principia Mathematica, Isaac Newton (1687) presents a disproof of Descartes' vortex theory of the motion of the planets.

The observation of star positions confirmed predictions of gravitational lensing made by Albert Einstein in the general theory of relativity published in 1915.

An example would be the ability of the quantum hypothesis, proposed by Max Planck in 1900, to account for the observed black-body spectrum, an experimental result that the existing classical Rayleigh–Jeans law could not predict.

In this case, the existence of a microtektite layer raining down upon the multiple intermixed species (including a Triceratops)[5] which were found at the site (the Tanis Konservat-Lagerstätte)[4]: page 7  served as the conclusive witness,[4] as cited in Science Daily.

[7] Lorne Falkenstein, reviewing Van Cleve expands the discussion of Experimentum crucis to the more general philosophical realm of Property dualism.

Isaac Newton performing his crucial prism experiment – the 'experimentum crucis' – in his Woolsthorpe Manor bedroom. Acrylic painting by Sascha Grusche (17 Dec 2015)