What if humans were only logical / rational?
As others have suggested, humans simply would not have come to pass. Yes, humans might not procreate or protect their offspring, but they also would not have avoided threats and dangers. I believe human existence would not be viable.
Emotions are an integral part of our first brain … our primal brain. Rationality does not replace the primal brain. Instead, our capacity to reason gives us the power to improve our responses to emotions-producing sensory input. Rationality is our problem solving brain. Whereas, emotions alert us to problems and opportunities. Both are handy.
Animals can live without problem solving. Evolution accomplishes that task through the generational selection of better attributes. But humans can not live without their primal brain.
It may be possible, as a supremely rational person, to develop behaviors such that emotions play a very minor role in survival or procreation. But this would take time. A long time. Still, the elimination of all emotional responses might dampen a drive for living—you know, too much of a good thing.
