Process Philosophy versus Substantialism
Process Philosophy holds that the underlying basis of reality is change, process and impermanence. Becoming is more basic than being, and existence is really just impermanence in slow-motion.
The converse view - Substantialism, holds that true reality is 'timeless' and based on permanent ideal forms. Change is accidental, whereas the substance is essential.
Traditional Western philosophy has always denied any full reality to change, which is conceived as only accidental and not essential.
Buddhism is, of course, the ultimate Process Philosophy. According to Buddhism, all functioning phenomena are impermanent and have no essential natures or inherent existence.
Dominance of Substantialism in Western thought
However, Substantialism has dominated Western philosophy from the time of Plato until the early twentieth century, and is still deeply embedded within our culture.
There were indeed Process Philosophers among the early Greeks. For example Heraclitus pointed out that no-one can step into the same river twice. It's not the same river nor is it the same person.
Nevertheless, the early process philosophers were ignored or forgotten, and the theory of ideal forms propounded by Plato was adopted by the later Greeks and then enthusiastically embraced by the Christian Church as a justification for Creationism, and the derived doctrines of Original Sin, the Fall of Man etc.
Darwinism and Process Philosophy
Creationists believe that species are unchanging and derive their forms by reference to a divine blueprint equivalent to Plato's 'essences' or 'ideal forms', which were fixed by God, unchanging and inherently existent. Bible-believing creationists claim that the world and all its species were created in six days of a single week around 4004 BC.
In contrast, Process philosophy is evolutionary. If all things are impermanent, constantly arising, becoming, changing and fading, then nothing exists 'from its own side' or by reference to some 'essence'.
Just as Buddhist philosophers had previously rejected the Platonic mechanism of production from 'ideal forms' as being the fallacy of 'production from inherently existent other', so the Darwinians came to the conclusion that a species does not correspond to any inherent reality, but is merely a concept that the mind imputes over interbreeding groups of plants and animals with similar characteristics (and the majority of their genes in common). The boundary between one species and another is not clear-cut.
The Michelson–Morley experiment
Just as the theory of evolution emphasised the dynamic processes of mutation and selection, rather than static species as the fundamental realities of biology, a similar transformation of thinking was to affect physics a few years later with the negative result of the Michelson–Morley experiment.
Until the nineteenth century, it was thought that all waves must propagate through matter. In other words, processes such as sound and water waves needed some substance to support their existence. It was therefore assumed that space was filled with a 'luminiferous aether' through which electromagnetic waves such as light, heat, radio waves, X-rays etc propagated like ripples on a pond. But the Michelson–Morley experiment demonstrated that this aether did not exist, and thus electromagnetic waves were standalone processes with no supporting substance. Quantum physics was later to show that the fundamental particles of matter are also processes.
Quantum Physics, Chemistry and Substantialism
Another blow to substantialism came from atomic physics. For 2000 years scientists believed that atoms were solid chunks of matter embodying the unchanging qualities of their elements. During the 20th century this has been superseded by subatomic physics, which views matter as being a manifestation of quantum interactions and processes.
In the 19th century chemists such as Mendeleev discovered numerical relationships between the elements. Then, with the development of subatomic physics, it was demonstrated that an element's properties aren't determined by its essential nature, but by the number of electrons orbiting its nucleus.
The worldview of quantum physics differs radically from that of classical physics. An an electron isn't actually a 'thing', it's a dynamic mathematical process known as a wavefunction.
Classical physics regarded the universe as being composed of clearly-defined building blocks ('things') which were 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.
Whitehead's Process Philosophy
The first real break with 2000 years of Western substantialism came with Alfred North Whitehead's Process Philosophy formulated in the 1920's: 'The process metaphysics elaborated in Process and Reality proposes that the fundamental elements of the universe are occasions of experience. According to this notion, what people commonly think of as concrete objects are actually successions of occasions of experience. Occasions of experience can be collected into groupings; something complex such as a human being is thus a grouping of many smaller occasions of experience.' - http://en.wikipedia.org/wiki/Process_philosophy
Whitehead on Buddhism and Christianity
Whether Whitehead's formulation of Process Philosophy was influenced by Buddhism, or whether he arrived at his conclusions independently and later realised their similarity with Buddhism, is unclear.
Whitehead famously remarked that "Christianity ... has always been a religion seeking a metaphysic, in contrast to Buddhism which is a metaphysic generating a religion." This observation is something worth considering in the current debates in the Buddhoblogosphere about whether Buddhism is a religion or a philosophy, and how far Buddhism and Christianity are compatible.
The underlying metaphysic that generates the religion of Buddhism is the Four Seals of Dharma.
'Existence' is really just impermanence in slow-motion.
To say that something exists is ultimately an arbitrary statement. All we are saying is that its rate of disintegration is negligible on the timescale of our lifetime. In reality, all functioning phenomena are impermanent - it's just that some are more impermanent than others.
All 'things' are impermanent, and so all things are in reality processes. Things do not stay the same from one millisecond to the next. Anything composed of atoms is composed of parts in a constant state of flux.
- Sean Robsville
Detailed Discussion of Process Philosophy and Buddhism
Essentialism, Ideal Forms, Plato, Buddhism and Generic Images
Evolution is no Threat to Buddhism
Existence, Impermanence and Emptiness in Buddhism
The Four Seals of Dharma
The Unreasonable Effectiveness of Mathematics in Science and Engineering
Essentialism in Physics, Chemistry and Biology
Sunyata - the emptiness of all things
Inherent Existence in Buddhist Philosophy
Quantum Buddhism - Buddhist Particle Physics