The current paper explores the rationality and associated non-emotionality of the psychopathic mind. This was undertaken because psychopaths in the corporate sphere (corporate psychopaths) have been identified as possessing the ability to rise to senior leadership positions within organisations from where they can wield enormous power over their colleagues, organisation and society. When in leadership, the psychopathic create emotional turbulence among their colleagues and subordinates, resulting in an extreme workplace environment. Nonetheless, findings as to the rationality of the psychopathic, include that psychopaths do embody the characteristics of economic rationality and may be the only rational human or ‘homo economicus’ that exists. Taken together with their total immorality and lack of all integrity this makes them the most serious threat to business ethics globally and a threat to the coherence of human society. These findings are important because such people care nothing for the future of humanity and their rationality is dedicated towards personal, short-term gratification. Potentially dire implications for humanity, organisations and society are drawn from this.