From the question:
You passively learn about something new.
With that key piece of information, I suggest absorb:
1 a : to take in (something, such as water) in a natural or gradual way
// a sponge absorbs water
// charcoal absorbs gas
// plant roots absorb water
1 b : to take in (knowledge, attitudes, etc.) : ACQUIRE, LEARN
// … convictions absorbed in youth …
— M. R. Cohen
So, in the example sentence:
Through this discussion I absorbed a lot of new perspectives.
If in this context, absorbed sounds a bit odd, the alternative acquire could be used instead.
Through this discussion I acquired a lot of new perspectives.