Complex sentence: The first lecture series was offered to Ludwig Wittgenstein, who eventually declined (as reported by his biographers) out of a discomfort with giving formal lectures where the audience would not be asking or answering questions.
Split into simpler sentences: The first lecture series was offered to Ludwig Wittgenstein, who eventually declined. According to his biographers, he felt uncomfortable giving formal lectures where the audience would not be asking or answering questions.