 Substance monism seems to be an implication of a combination of views held by Cesalpino: (1) the view that the active intellect is a substance that is capable of self-reflection; (2) the view that the active intellect “perfects everything”; and (3) the view that the active intellect “implants into things a striving for perfection insofar as it is intellection” (Cesalpino 1593: fol. 35v). Thus, the substantiality of the active intellect is characterized as being due to its capability of self-reflection, and it is this specific activity that is understood as the origin of the activity of natural things, not only of minds. Consequently, Cesalpino maintains that the plurality of substances cannot be based on considerations concerning human self-reflection. His argument invokes the possibility of a temporary split in the self-consciousness of the active intellect—the possibility that during the life-time of a living being the part of the active intellect that animates this living being undergoes a stream of acts of self-reflection that are isolated from the stream of acts of self-reflection that other parts of the active intellect undergo at the same time. If so, individual minds would be “included in a unique intelligence as parts are contained in a whole or as a smaller number is contained in a larger number” (Cesalpino 1593: fol. 36r).