Most thinking is passive.
Productive thinking is active.
Active thinking requires instantiating the idea. Taking the abstract contents of a thought and breathing it into the world, and onto the logical order that sensibilities require.
Before writing was economical, before paper and ink was commonly used and accessible and mass produced, memory palaces provided a temporal spatial realm to exercise ideas and hang them on the scaffolding of the mind. (Roman Lull; Cicero)
Conversing out loud is great, but you can’t go back and refer to those thoughts in the future.
Writing thoughts down is best. It creates a static permanency that can be eternally revisited. Thoughts embedded in symbols and signs, imbued with meaning and association,