Carrying the musical analogy further may help to clarify what it 

means to speak of soul as a distinct being and as causal form. Consider 

Mozart’s String Quartet number 16. It came into existence in Mozart’s 

imagination, and he encoded it in musical notation. It has active existence 

(or “life”) whenever four musicians get together and play it. It is not the 

musicians who make the quartet exist. Rather, it is the existence of the Introduction 13

quartet as a form that governs the coordinated actions of the musicians. 

Any four capable musicians playing the relevant instruments can serve as 

the material foundation for the life of that piece of music, but only because 

the form of the music is already there to organize their movements.

Now consider a squirrel. Its life consists of certain activities, and to be 

alive as a squirrel means to have the capacities to engage in those activities. 

A squirrel that is not properly equipped for “squirreling” will not continue 

to be a squirrel for long. It needs the relevant parts, and for these parts to do 

their work it requires that they be composed of the suitable materials. Since 

the materials come and go, it is not, strictly speaking, the materials that 

are responsible for its being a squirrel. Rather, it is having the right kind of 

materials in the right arrangement. 

M. Shiffman *Aristotle, De Anima