Firstly Aristotle says that each object has a material cause. The material cause it the physical material or matter that the object is made from. For example, the matter that a book is made from is paper and ink, this is its material cause. In addition to this, Aristotle said that all material has potential for change. So the pages of the book could be written on or some may be ripped out. However it still remains a ‘book’.
The second of Aristotle’s explanations is the efficient cause. The efficient cause is the agent or cause of the thing coming to exist as it is. For example, the existence of a book is brought about by the author who wrote it and perhaps the artist who illustrated is and the person who printed it and put it together.
Aristotle believed that all objects have a formal cause. The formal cause refers to what gives the object its form or ‘structure’. In other words, it’s the shape and the characteristics that make it recognisable. The formal cause of a book is the particular way that the pages are arranged. We recognise a book because it has a front and back cover with pages in between.
Alone, these three Causes that I have underlined above explain what the object is and how it came into being, but that is that. They do not explain what the object does, or what reason it was made. Without the Final Cause, this theory does not explain why, but only how.
The Final Cause therefore explains the purpose of a thing's existence, and what it is for. In other words, the final cause is essentially what the object was created for. For example, the final cause of a textbook would be to
assist the reader’s learning. The final cause of a story book would be to entertain the reader and the final cause of a notebook, to write in.
Aristotle said that all objects have actuality (what they are and what they are capable of), and potentiality (what the object could become). His theory was that once an object had fulfilled its purpose- the final cause or its potentiality, it has achieved greatness and perfection. When an object is reaching its potentiality is said to be in motion. So when a notebook is being written in, it is in motion because it is fulfilling its final cause. The notebook has then achieved greatness and perfection.
To conclude, Aristotle tried to explain the nature of all things- how they exist in the way they do, by suggesting the Four Causes. The material these included the material cause, the efficient cause, the formal cause and the final cause. He believed that they could be applied to everything because if something exists then it must have a creator and purpose.