Thoughts not shared are not thoughts at all. They are words in the mind. They have not been identified, or commented on. I think it takes two or more people to make a thought. One to have the words, and one to respond. The response gives life to the words, turning it into a thought. The thought is the sound. It became that when it was shared.
Life compounds when it is shared. The more people we meet, the more words we share, the more love we give, the more life we live.