Abstract

Thomas Aquinas holds that the actual content of our thought is not accessible for any creature, and that free will cannot be superseded. These theses are founded on the spiritual condition of our intelligence and will, which makes them directly invulnerable to any intervention on our body. On the other hand, he enthrones the will as the keeper of interiority: it precludes a full transparency that would make our free decision to communicate superfluous, and it exert an inalienable control over the action through which we direct ourselves to the good. In this sense, Aquinas departs from reductionist accounts, which either refuse the existence of free will, suppressing the reason to protect its expression, or face the difficulty of explaining the meaning and justification of the rights that are claimed for free will. However, Thomas Aquinas admits the possibility of indirectly accessing our minds through the knowledge of brain states and of influencing our will through passions by means of alterations of our organisms. Although this possibility was not within the reach of the human being in his time, he considered it was within the reach of separated substances. The consideration of the limits of their perspicacity and control sheds light on the possibilities that neurotechnology can allow in the future. The existence of an unassailable stronghold that guarantees our interiority and free will legitimates our right to be respected but does not make their protection superfluous.