The mind, body and soul are connected therefore the soul must die with the body, therefore the soul must be mortal, therefore one will experience nothing after death, therefore one should not fear death. That is the Super Sparknotes version of Book III of Lucretius’ On the Nature of Things. It looks so tidy on the page laid out like that, but when broken down and considered with respect to human nature and existence, it becomes far more complex, as many things often do when taken out of the context of academic theory and applied to, for lack of a better term, real life.
Lucretius introduces his argument with an explanation as to why death evokes such fear while at the same time assuring that he will eliminate those fears by disproving them. “For just like children who tremble and fear everything / in the dark night, so we are afraid in the light sometimes / of things that ought to be no more feared than /the things that children tremble at and imagine will happen.” (3.87-89)
He begins with “now I maintain that the mind and soul are held joined together / with each other and make one nature from each other […] the other part of the soul, spread through the entire body, / obeys and is moved by the direction and impulse of the mind” (3.135-3.140). He further explains the mind, body, and soul connection with, “and neither the power of the body nor the soul is seen to be able / to feel sensations separately for itself without the energy of the other, / but sensation is kindled and ignited throughout our flesh / by shared and interdependent movements from both sides. / Moreover the body is never created by itself / nor does it grow on its own nor is it seen to endure after death” (3.333). The line in this passage most revealing of Lucretius’ argument is “so too does their nature stand conjoined”. Here he is explaining that the body and soul operate in the same manner; when the body dies is it is clearly stagnant, and the same applies to the soul. To Lucretius, this works in the opposite way as well, “For without the intelligence and mind no part of the soul / can reside in the limbs for even a tiny part of time […] but a person remains in life whose intelligence and mind remains”(3.398-399). This is explained further as his argument develops.
As stated before, when the body dies the soul dies as well. Lucretius follows this by providing evidence to support this claim. He first affirms that “[the soul] is made up of exceedingly fine particles” which explains why, despite the physical nature of the soul, “when the whole soul has now left the entire body, / still the external configuration of the limbs / preserves itself unchanged and not a speck of weight is lost” (3.68; 3.215-217).
A second example of this is Lucretius explanation of fear. “When the mind has been stirred by a more violent fear, we see / that the entire soul is equally affected throughout the limbs, / next sweat and pallor break out over the whole / body, the tongue...