Unity of Form and Substance

I was reading a book (Sophie's World) today and this particular section of the book reminded me of sketching class today:

“Substance” always contains the potentiality to realize a specific “form.” We could say that “substance” always strives toward achieving an innate potentiality. Every change in nature, according to Aristotle, is a transformation of substance from the “potential” to the “actual.” 

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A sculptor is working on a large block of granite. He hacks away at the formless block every day. One day a little boy comes by and says, “What are you looking for?”  

“Wait and see,” answers the sculptor. After a few days the little boy 

comes back, and now the sculptor has carved a beautiful horse out of the 

granite. The boy stares at it in amazement, then he turns to the sculptor and says, “How did you know it was in there?” 

How indeed! In a sense, the sculptor had seen the horse’s form in the block of granite, because that particular block of granite had the potentiality to be formed into the shape or a horse. Similarly Aristotle believed that everything in nature has the potentiality of realizing, or achieving, a specific “form.” 

Aristotle believed that reality consisted of separate things that make up a unity of form and substance. The “substance” is what things are made of, while the “form” is each thing’s specific characteristics.