 In his principal philosophical work, the dissertation on Impassivity, he argues against the claim that the soul can be endowed with a passive faculty of sensation, a position he identifies as stemming from Descartes (Amo 1734a: 13–14 [2020: 179]). Amo understands the human mind to be a species of spirit, which is purely active and immaterial. Were the mind to be endowed with a capacity to sense, it would have to be able to receive ideas, and in one of three ways: by “communication” (i.e., in the manner that fire “communicates” its heat to an object), by penetration (i.e., through interposition of another entity), or by direct contact (Amo 1734a: 5 [2020: 161]). Amo argues that it is impossible to conceive of the mind receiving ideas in any of these ways as it would violate its essence as a spontaneous being and its immaterial nature precludes transmission through contact (for discussion, see Walsh 2019). Perplexingly, in spite of contending for the soul’s impassivity, Amo endorses the Aristotelian dictum that “nothing is in the intellect that was not first in the senses” (Amo 1734b: 6). Amo also affirms the mind’s capacity to influence the body (Amo 1734a: 8 [2020: 169]), though without accounting for how he takes this to be possible or explicitly engaging with the debate relating to the pre-established harmony. Nonetheless, in his lifetime Amo was identified by at least one influential historian as a Wolffian thinker (Ludovici 1738: §202).