In Book 3 of On the Nature of Things, Lucretius addresses the idea that inspired Dante to consign Epicurus to the sixth circle of Hell: that the soul is not immortal. In making his argument, Lucretius makes a compelling case, given the observational capacities of his time, for the mind as an emergent material phenomenon, a position borne out compellingly by modern neuro-science. In making this case for the physicality and thus the mortality of the mind, which he posits as one component of a soul consisting of both mind and spirit, Lucretius also gets into areas pertaining to mental health, a matter of urgent current interest. These questions relate closely, I think, to the real psychological dangers posed by the stigmatization of mental illness on the one hand and religious threats of eternal damnation on the other. The episode therefore ends with a somewhat personal take on the clear and present danger that a non-naturalistic understanding of the mind and soul poses to human wellbeing.