Reading the paper by Lieb "The stability of matter", it is clear from the start that quantum mechanics is absolutely necessary to solve this problem. However, I assume this question was thought of before the birth of Quantum Mechancis. If so, what were the main hypotheses? It seems unsolvable from a classical perspective, and therefore it could be a historically relevant pathway to the formation of Quantum Mechancis. However, I have never seen it mentioned in any historical perspective. So what solves this apparent "paradox"?
Alternative link: The stability of matter, Elliott H. Lieb (1976)