The Full Epicurean Reasoning Regarding a Material Universe

I wanted to start this thread so that we can create a concise explanation of the reasoning from start to finish about how we come to understand that the universe is a material universe. This would be based on both Letter to Pythocles and Letter to Herodotus...as well as Lucretius. The purpose of this is so that we can all easily explain this both to ourselves and to others.

Also, to see if there is anything we need to add from modern understanding, or is the Epicurean explanation complete.

More coming soon.

Creating a concise explanation would also be the basis and reasoning behind recognizing that the soul is mortal and that the gods are indifferent.

This might be of interest: Chapter 2 - "Atomic Worlds" of Catherine Wilson's book Epicureanism: A Very Short Introduction (but I don't have it)...here is a link to the overview:

https://academic.oup.com/book/746/chapter-abstract/135401379?login=false&redirectedFrom=fulltext

Quote

Wilson's insights into atomic worlds highlight a shift from traditional philosophical views that often incorporate divine oversight or eternal consequences. Instead, she advocates for a perspective grounded in materialism and the understanding of nature, which can lead to a more liberated and pleasurable existence.