Theories about all things being reducible to small particles that cannot be seen with the naked eye and these being the basis and composition of all things go back to the fifth-century BCE. Nor was ancient atomism an isolated theory formulated by a long thinker. It became a core part of natural philosophy. It was philosophy that spawned what we call ‘science’, perhaps a surprise when philosophy and science seem so far apart in our own society. The core of all theories was that nothing was infinitely divisible – the Greek word ‘atoma’ means the ‘un-cuttable’. Some scholars argue that atomism was to be found in Pythagoras, but the earliest thinkers that we know of for sure were Leucippus and Democritus of Abdera.
Ethical theories, explanations about the true nature of the gods, knowledge, were all built upon theories of atomism, and came particularly to be identified with the teachings of the Epicurean school. Events were believed to be caused by disturbances, movement between, or rearrangement of the atoms that underpinned all existence. The arguments employed to defend these views show a clear and scientific logic.
I take as my example a passage from Lucretius. Lucretius was a Roman poet and Epicurean philosopher, writing in the 50s BCE. His beautiful, didactic work de Rerum Natura, written in the epic hexameter metre, is a scientific work of immense importance, with the first two books dedicated to an argument in favour of atomism (Book 1.311-321):
quin etiam multis solis redeuntibus annis
anulus in digito subter tenuatur habendo,
stilicidi casus lapidem cavat, uncus aratri
ferreus occulte decrescit vomer in arvis,
strataque iam volgi pedibus detrita viarum
saxea conspicimus; tum portas propter aena
signa manus dextras ostendunt adtenuari
saepe salutantum tactu praeterque meantum.
haec igitur minui, cum sint detrita, videmus.
sed quae corpora decedant in tempore quoque,
invida praeclusit speciem natura videndi.
A ring upon the finger is worn away underneath with the returning years, and the drippings of rain from the roof hollow out the stone, the hook of the plough made of iron secretly diminishes amid the fields, and we see the stone-laid ways worn down by the feet of many; then near the gates, the bronze statues show right hands that are being thinned at the frequent touch of the passers-by who greet them. We, therefore see how these things are diminished, when they have been worn down. But which are the bodies that depart at whichever time, the grudging nature of seeing shuts off from our sight,
Atomism is perhaps my favourite ‘originally ancient’ theory. Through logic, curiosity, and close observation a theory that could be classed as an ‘advance’ in modern science was born 2,500 years ago, and was 2,000 years ago beautifully articulated by a true philosopher and artist.
For a more detailed account, see:
https://plato.stanford.edu/entries/atomism-ancient/#AtomBefoLeuc