Xin
I've just finished reading The Path by Michael Puett and Christine Gross-Loh: a wonderful exploration of Chinese philosophy, which is much more concerned with the practicalities of how to live well than high-flown abstractions.
One beautiful word I came across in this book is xin. This can be translated as both “heart” and “mind”. The Chinese don't distinguish between the emotional and rational parts of our nature - so phrases like “go with your head, not your heart” aren't easily translated into Chinese.
I love this.
The distinction we draw between the emotional and rational aspects of ourselves leaves us open to favouring one over the other, thus ignoring an important part of who we are. If we make decisions on a purely rational basis, we may be inhumanly cold. If we act solely on emotion, we may be inhumanly irrational.
Our wonderful mind is what makes us human. This mind is both emotional and rational - it is xin. It is when we act according to xin - the synthesis of 'head' and 'heart' - that we are at our best.