Hirshhorn began teaching initially in Utrecht (The Netherlands) and then, as from 1985, in Brussels. No one could foresee what this would lead to, but as it turned out, from these two classes, in Utrecht and Brussels, over the course of ten years, there came a respectable number of well-known violinists - soloists and performers in ensembles – as well as concertmasters of major orchestras. Usually you don’t expect great achievements in teaching from outstanding performers, especially in such a brief period of time, but nonetheless his achievements were beyond doubt. The reminiscences of Hirshhorn’s students can be read in the section of memoirs. It is curious how they speak about him now, twenty years later, with such eagerness and in such detail. They recall so much about him. It is not every pedagogue who can boast having left such strong impressions on his students. As regards music, many say that Hirshhorn achieved his true musical heights most often in chamber settings, among his own people, and none of them can forget or will forget to the end of their days what they heard from Philippe in the classroom. It is exciting just to read about this (see, for example, the reminiscences of Gudrun Vercampt).
Judging by the words of Philippe’s students, his instructional credo can be understood as follows: to help them to express themselves at fully as possible – exactly themselves, and without regard to whatever else was going on. Discussions about discovering the individuality of pupils have been going on since time immemorial, and only lazy ones are not repeating the worn phrases about the value of one’s musical personality. But where do words end and deeds begin? In the case of Hirshhorn, we see precisely deeds, which he considered to be of primary importance and which he took with all possible seriousness. Possibly that is why, though he was not a pedagogue for "instrumental technical solutions," and was not enthusiastic about giving advice on fingering, he managed to achieve such outstanding results.