So … could there have been more substances than there in fact are? Spinoza’s answer is no, which means that there are no merely possible substances.
Samuel Newlands: Spinoza’s Modal Metaphysics | plato.stanford.edu 2018-09-14
Also hätte Spinoza für possible worlds, Paralleluniversen etc. wohl nichts übrig. Vgl. Smolins Ansicht, es gebe nur eine Zeit.