I just came across this article (link below) via Ed Yong on Twitter (@edyong209) about Tatiana and Krista Hogan, two conjoined twins who, if that’s not unique enough, actually share a bridge across their thalamus, a part of the brain vital to processing and relaying sensory information to other parts of the brain. They apparently can see through each other’s eyes and even share thoughts. Stories about conjoined twins are baffling enough, but then you add this particularity and it gets even more baffling.
I’ve been spending a great deal of time over the last year or so thinking about what it means to be human. As a Westerner, my thoughts are inevitably framed by a lens of individualism and the importance of the the “person” within each of us. This story does more than just tickle that framework. If they share a thalamus and thoughts, are they unique or distinct from each other? If not, they are still clearly human so what does this do to our description of what it means to be a human? Can the story help us to redefine “humanness”?