僕は実験方法を学んでいたのではなかったし、実験を再現する方法を学んでいるのでさえなかった。

、。

I wasn't learning experimental methods, and I wasn't even learning how to reproduce experiments.

Literal

I [topic-は] experiment-method [object-を] was-learning [nominalizer-の] [copula-で] [topic-は] was-not [reasoning-し], experiment [object-を] reproduce method [object-を] am-learning [nominalizer-の] [copula-で] even was-not.

Complex negation with parallel clauses joined by し. ~のではなかった uses explanatory の + ではなかった for emphatic negation — 'it wasn't that I was learning X.' ~でさえなかった adds でさえ ('not even') for further emphasis. An unusually dense sentence from an academic or philosophical context.