Is Pain Metaphysically Evil (Malum Simpliciter)?

Contrary to the commonly assumed opinion that Christianity sees pain as intrinsically evil – where evil is defined as the lack of something good – Aquinas defines pain not as a privation but rather a passion of the soul, i.e., an emotion that depends on sensual and/or intellective cognition of something evil, is good in itself, and may serve a purpose. This article offers a formalized version of the Thomistic definition of pain and related negative (unpleasant) emotions experienced by humans. It also compares and contrasts this view with some contemporary scientific and philosophical models of pain.