There is this sentence which I can't work out the meaning. "They have a unique identity between language and thought that means they cannot conceptualize a lie. This also means that deception, fiction and metaphors are completely alien to them." I can't understand the 1st sentence "They have... that". What is the meaning of Identity here and what is the effect of between prep and it's complement on the meaning of identity? Can somebody kindly explain to me what is the meaning of first sentence?