De anodinis medicamentis eorumque causis et usibus Physica & Medica consideratio in Theses aliquot digesta

Galen, 2, On Affected Parts, chapter 2, and On the Composition of Medicines according to Places, 7.

VI.
Pain, according to Galen, is a sad sensation arising from the solution of continuity the disruption of physical integrity, as the containing cause; whether that cause is manifest from burning, cutting, or gnawing things, or hidden from the internal compression or distension of the viscera and parts.

Hieronymus Montuus, On the Decomposition of Disease, book 1, chapter 2.

VII.
Others, however, whose opinion I more approve, resist both of Galen's positions, defining Pain as a passion a sensation or affection not of touch, but following the cognition and judgment of the ruling faculty of the sense. For first we sense, then we judge; according to the reason of which judgment, we perceive either pain, or joy, or something mixed, at almost the same time.

VIII.
That the solution of continuity is not the containing cause of pain is proven by the example of fools: some of whom, because of wounds, even if very gravely inflicted, are not moved, just as melancholics or phrenetics are not when they vex, rend, and miserably lacerate themselves while laughing; indeed, by this very act, they exhilarate their eyes and mind. It is so far from the truth that they are affected by even the lightest pain on account of a solution of continuity.

IX.
Wherefore, it is not an evil affection of the nerves or of any sensible part, but the perception of the molesting sense that most directly causes pain; because fools, maniacs, and the raging (on account of a fault in the Ruling faculty) are deprived of this perception, it is no wonder if they delight in sprinkling themselves with their own blood, and are not changed by the stimuli of opposing things inherent in them.

X.
But if the cause of pain consists in the perception of the sense, as I have rendered proven,