Ich habe Philosophie studiert!
"I have studied Philosophy"? The participle studiert at the end of the sentence. But this verbal parenthesis (haben/sein ... participle)
is not the only particularity.
In English, you use the Present Perfect only if "result of actions in the past is important in the present".
In German, you may use it for every moment in the past.
So, what is the difference between Imperfekt/Präteritum and Perfekt? Harald Weinrich, a famous linguist, puts it like this: Präteritum is the tense of narrations. This means that
the listener should wait (remember the suspension of disbelief?) until the story is finished, every element is there, every reason explained.
With the Perfekt instead,
Weinrich states, we express elements of the past that singularly are introduced into the context of actual reasoning. (Weinrich: Textlinguistik)
Philosophers prefer the present tense, talking about what they believe to be valid. When they write about the past, usually they use Präteritum/Imperfekt, proposing narrations,
and not conceiving they might be interrupted. Hegel, for example, in his "Philosophy of History", uses the present tense even when he is treating ancient Persians or Greeks,
as it is the principle, historically given, but as such eternal, he is interested in. For longer narrations of events, he choses Präteritum.There is only one ecception. When he refers to Greek philosophers individually, he
introduces their ideas using the Perfekt tense, as if he were citing contemporary colleagues whose idea may be introduced, one by one, or rejected today.
Some examples (simplified sentences):
Von Anaxagoras hat Sokrates diesen Gedanken aufgenommen ….
Sokrates hat aus seinem Dämon geschöpft, und so haben die Volksführer und das Volk aus sich die Beschlüsse genommen.
Aristophanes hat im Ernst für das Wohl des Vaterlandes geschrieben und gedichtet.
Sokrates hat das Subjekt als entscheidend (decisive) gegen Vaterland und Sitte gesetzt und sich somit zum Orakel im griechischen Sinne gemacht.