 According to the theory of physical influx, there is an inflow between cause and effect; in other words, there is intersubstantial causation among finite (i.e., non-divine) substances. So, for instance, when Jimi Hendrix appears to strum his guitar, he really is the cause of the vibration of the strings. In this case, motion is a mode or state of the body of Hendrix and is transferred or communicated to the body of his guitar. Interestingly, the term ‘physical’ notwithstanding, the theory of physical influx is not limited to material finite substances. For physical influx sometimes is invoked to explain the causal interaction among immaterial finite substances (e.g., minds) and material finite substances (e.g., bodies). Accordingly, it is more accurate to take the term ‘physical’ to mean natural rather than material. Francisco Suarez, Thomas Hobbes, Pierre Gassendi, and Robert Boyle, among others, subscribed to some variety of physical influx.