The difference between being gullible and being ready to change (beginner’s mind) is the difference between a database and a blockchain. The latter preserves history and has more context to rely on. It gives up the illusion of static perfection for the messy reality of change.
Being gullible is like being an insecure database. Being ready to change is like having the capability to amend and lock in the mistake for all to see as part of history.