Essentialism in Physics, Chemistry and Biology
For the best part of two thousand years essentialism held sway over the Western mind, firstly in the form of Platonic essences, then as the unchanging species and races of the Bible, and finally as nineteenth century atomic substantialism.
The first cracks in the essentialist edifice are apparent in retrospect with Newton's laws of motion.
Before Newton, the heavenly bodies wandered around the firmament according to their essential natures as decreed by the 'Unmoved Mover'.
After Newton, the stars, planets, moons, comets and asteroids moved according to the same mathematical relationships.
Before Newton, stars, planets, moons, comets and asteroids were separate entities. After Newton there was a continuity in size and composition from the tiniest 'grain of sand shooting star' through meteorites, asteroids, comets, moons, miniplanets, small planets, gas giants, brown dwarfs and all the different sizes of stars.
Before Newton there was the concept of the 'Unmoved Mover'. After Newton every action had an equal and opposite reaction. As a consequence anything that produced a change was itself changed. Therefore ALL functioning things must be impermanent. These observations were never taken to their logical conclusion by European philosophers in Newton's day, possibly because heresy still attracted severe punishment in most European countries.
Chemistry provided a bastion for essentialism up to the late nineteenth century. All substances were composed of atoms of about 80 known elements. Every atom of a particular element was identical with another atom of the same element, and derived its properties from the essential nature of that element. The atom was fundamental and unchangeable.
The first hint of atomic substructures came from the work of Mendeleev, who published his periodic table in 1869. He left gaps in his table for as yet undiscovered elements and was able to predict their properties.
Work on radioactivity in the early 20th century demonstrated that atoms were not fundamental but were composed of elementary particles - electrons, protons and neutrons. But these elementary particles did not act like classical 'things'. They were only knowable by interactions with other particles, and the mere act of observation changed their properties in an indereminate way.
Even worse, their 'essential nature' seemed to change radically according to how they were observed. If you set up your experiment to observe them as particles, then they behaved as particles. If you set it up to observe them as waves, then they behaved as waves.
Evolution and Genesis
'The Origin of the Species' was the first major blow against essentialism in the West. In 'Darwin's Dangerous Idea' Daniel Dennett says ' Even today Darwin's overthrow of essentialism has not been completely assimilated .... the Darwinian mutation, which at first seemed to be just a new way of thinking about kinds in biology, can spread to other phenomena and other disciplines, as we shall see. There are persistent problems both inside and outside biology that readily dissolve once we adopt the Darwinian perspective on what makes a thing the sort of thing it is, but the tradition-bound resistance to this idea persists.'
The worldview of quantum physics differs radically from that of classical physics. Classical physics regards the universe as being composed of clearly-defined building blocks ('things') which are specified by their own internal properties. Quantum physics sees the universe as an ever-changing set of relationships between entities which can be defined only in terms of those relationships.
Buddhism and science
The full implications of the collapse of essentialism have yet to fully permeate the western psyche. But the radical change in the way that science views the world which took place between 1850 and 1950, has brought western thought far more in line with Buddhist philosophy than at any time in the past 2500 years. This may partly explain the rapidly growing interest in Buddhism among scientifically literate westerners.