Joseph Goebbels did not hold a PhD in philosophy; his doctorate was a PHD, (which means doctor of Philosophy, in the same way a BA degree is a bachelor of arts, but can be in any creative subject not necessarily art)
Goebbels area study and dissertation was Literature, meaning he was a Doctor of theatrical literature, specialising in 19th century Playwrights, as it was his aim to become a playwright himself, he failed miserably, with only a string of un-produced and rejected plays making up his portfolio, until he moved in to political promotion and propaganda instead.
His PHD supervisor was the illustrious Jewish academic Max Freiherr von Waldberg.
Some theorise it was his failed post academic career being blamed on Max Freiherr not being honest about his lack of talent that lead to his later extreme anti-Semitism especially against Jewish intellectuals.
It is true however that in Hitler's inner circle he was the only Intellectual, having earned his University education by scholarship and pure effort, before becoming embittered and corrupted by the lure of vile fascism.

Not the Nazi Goebbels? No respect for Nazis

Hey, congrats, dude! Gonna check it out. [edit] Okay, bought it with one-click. My book comes out in June, hint hint.