Active learning: Someone tells you what to learn, how to learn it, on a set schedule, on pre-selected standardized topics.
Passive learning: You let your mind wander with no intended destination. You read and learn broadly, talk to people from various backgrounds, and stumble haphazardly across topics you had never considered but spark your curiosity, often because it’s the topic you happen to need at that specific time of your life.
Most of what I’ve learned in life has come from passive learning.