You lost the essence of the article by changing the title to a trite observation. The point the author is (presumably) making is a bit outrageous: that you not live just in your own brain but in the brain of the others you're related to.

I say presumably because I haven't read Siegel's book, but am extrapolating from the same thread which was woven by Hofstadter in "I am a Strange Loop". A more popular yet similar exposition of this idea is the word Ubuntu, which you can roughly grasp using the aphorism "A person is a person through other people".