Lucretius was a Roman poet who lived in the first century BCE. His one known work, De rerum natura (On the Nature of Things), was a poem expounding upon atomism and Epicurean ethics. It was lost for a thousand years after the fall of Rome and Christianity discarded Epicurean works, since it wasn't deemed compatible,. It was first rediscovered in 1417 in a German monastery.

The main points of the poem remain remarkable for a work twenty-one hundred years old.

Physics:
1. Everything consists of atoms moving about in space which combine together.
2. There is an indeterminacy to atomic motion called the swerve which accounts for how atoms can randomly combine together.
3. Space, time and atoms are infinite and eternal, while everything else is impermanent.
4. There are a finite kinds of atoms which can only form in certain ways, like an alphabet combines to make words.
5. The world we live in today is the result of an infinite number of random combinations resulting in the current configuration.

Here we see precursors to our modern understanding of particles, quantum mechanics, cosmology, entropy and chemistry. Of course it's lacking in various ways, but absolutely ground breaking for 2100 years ago!

Biology
1. Humans are no better and are related to other life forms.
2. The various features of life forms came about because they were adaptive and resulted in reproductive success.
3. The soul (which animates the body) is material and dies with the body.

We have a precursor to evolution here and a denial of any afterlife or spirits.

Epistemology
1. Perception gives us faithful knowledge of the world via interaction with films of atoms coming off things themselves and forming sensations in us via our sensory organs
2. The mind sometimes makes mistakes and creates hallucinations and illusions.

Lucretius is providing an answer to skepticism with his empiricism, which is a kind of direct realism. Errors stem from the mind and not perception.

Ethics
1. Maximizing pleasure and minimizing pain is the good humans should strive for.
2. This pleasure seeking includes moderation in accordance with natural limitations humans face.
3. Friendship, charity and intellectual pursuit are considered part of the good life.
4. Sex is natural and should be pursued.
5. However, romantic love is a delusion and results in pain.
6. Embracing atomism means we can lose our fear of the afterlife.
7. There is no need to seek status or wealth or engage in violent conflict, since those things bring pain and are based on delusions which atomism can cure.
8. The gods exist but they do not care what we do, so there is no reason to fear or sacrifice to them.

We can see why Epicureanism was anathema to Orthodox Christianity and had to be forgotten, since hedonism is opposed to emulating the life of the suffering savior because of sin. And atomism as a materialistic doctrine supported atheism, even though Lucretius's poem was not atheistic.

Metaphysics
1. The ontology of universe consists of atoms swerving in the void, and the things they make up.
2. The universe is eternal and uncreated.
3. The soul is material.
3. Free will comes form atoms swerving.

Lucretius supports mereology/emergentism along with the soul and free will, anticipating modern arguments based on indeterminacy. The soul could be viewed as vitalism, or a stand in for the nervous system. His philosophy is also nominalistic, since there are no universals, just individual objects composed of atoms. And there are no laws of nature so to speak, just the swerving atoms, although their combinatorial abilities are causal (even though the swerve is not).

One has to wonder how Western history would have turned out differently if Lucretius/Epicurus had become the dominant ideology instead of Christianity.