I meet lots of people whose open-mindedness is not shaped by any knowledge of the constraints on the diversity of phenomena in the world. For example, the integers are universal, and the elements instantiate the integers, from 1proton (Hydrogen) to two protons (Helium) on up to heavy elements with nanosecond lives that end when their giant heavy nucleus decays. People assume it is possible that other worlds, elsewhere in the galaxy, have elements that do not appear on the periodic table. They often insist on this, because other worlds are surely a matter that calls for open-mindedness.
Read the Periodic Table of the Elements from left to right, row by row, and watch the building of reality as proton after proton is added to the nucleus to make each element. I don't mean that the actual elements are formed by a process of adding protons; I mean it heuristically, that is, as an aid to thought: the nucleus of each element on the table is one proton larger than the nucleus of its predecessor. How they get formed is a matter of the life cycles of stars, including the formation of heavier-than-iron elements in supernova conditions. But let's bracket out for a moment the diachronic, time-bound processes by which the elements are formed, and just look at the synchronic snapshot of the current situation. The world is composed of energy, spacetime, and these hundred elements. The miracle of physical chemistry is that a primate came to understand just how the numbers spell out the physical world; how it is that the addition of a proton to the nucleus gives rise macroscopically to a completely different substance; how the healthful precious silver of 47 protons becomes the toxic heavy metal cadmium when a 48th proton is present.
4 weeks ago