As Hermann indicated in the title of her main work, "Die naturphilosophischen Grundlagen der Quantenmechanik", philosophy of nature plays an important role in her critical study of quantum mechanics. However, what exactly does Hermann mean by "philosophy of nature"? A new analysis of the largely forgotten philosophy of nature by Jakob Friedrich Fries (and its interpretation by Hermann's mentor Leonard Nelson) will allow us to judge to what degree Hermann's work has been influenced and guided by Friesian philosophy. I will show that the aim, methodology and understanding of her philosophical work have been determined by Friesian philosophy. However, although Friesian philosophy is pervasive in the elaboration of her ideas, Hermann did not pedantically follow the teachings of Fries or Nelson, and presented her own original contribution to Friesian philosophy (as well as she did for physics). Hermann both grounds her ideas in, and expands upon, Friesian philosophy.