Question about Marxism

*Disclaimer : I'm just a guy who has a trivial question about Marxism which I read in a book recently, and found this subreddit just today. Dunno if I'm doing this right.So according to what I read, part of Marxism came from Hegel's Dialectic(dunno if that's the right word; I didn't read it in English)-which says at first there's a These, but an opposing Antithese comes up, and the two together form a result called a Synthesis. This Synthesis becomes another These, and this thing repeats itself endlessly. Ex) These: There's a feudal society / AntiThese : But the Bourgeois comes up / Synthesis : Revolution occurs and Capitalism emerges. I learned that Marx took this to history and asserted five stages of historical societies-something like ancient/primitive Communism to Slavery-based society to Feudal society to modern Capitalism to perfect Communism (These prob aren't the right words; again, I didn't read it in English).The Question is: If Marx believed in the theory that History eternally changes and progresses through Dialectic, then wouldn't that mean the fifth stage of classless communism(Marx's ultimate goal, I guess) will inevitably fall, too? What's to stop the never-ending cycle of history? via /r/communism https://ift.tt/3h7q0Gn