Complex sentence: Keown attempts to overcome this problem by proposing that an enlightened person is beyond the accumulative experience of good deeds (merit, "puñña"), since he is already perfected and therefore does not need to accumulate goodness and the resulting happiness anymore.
Split into simpler sentences: Keown attempts to overcome this problem by proposing that an enlightened person is beyond the accumulative experience of good deeds (merit, "puñña"), since he is already perfected. He therefore does not need to accumulate goodness and the resulting happiness anymore.