Another of Aristotle’s contributions to classical physics was on Causality

This model gave a simple, perfect justification for falling rocks, rising flames, and the motion of air, but was deficient in clarifying the ‘violent motion’. For example, when a stone is hurled from a sling, it continues to move even after it had left the sling, yet, by Aristotelian physics, the stone’s natural state is rest and should have dropped to the ground soon after leaving the sling. He explained that the air in front of the stone was disturbed, swirled behind and pushed the stone forward, thus the difference between ‘natural’ downward movement and unnatural violent movement.

Aristotle also delved into optics and offered very accurate information regarding the same as compared to the information available then, for example, he was among the first people to write on the workings of the camera. He constructed a device with a dark compartment and with an aperture to let in light and used this device to study the sun. He concluded that the sun would still be shown as a circular object irrespective of the shape of the hole. This has been modified in modern cameras where it is known as the diaphragm. Aristotle also noted that the size of the image depended on the distance between the aperture and the screen (Cooper, 2007, pp. 175)

Another of Aristotle’s contributions to classical physics was on Causality, he asserted that there were four kinds of causes:

• A substance’s material cause is the material that it comprises of, e.g. for a chair, this might be wood, or bronze/ marble for a sculpture;
• A substance’s formal cause is its form, that is, the organization of that substance;
• A substance’s efficient or moving cause is the key cause of the change or rest;
• A substance’s final cause is its purpose or objective, for example, for a seed, it might be a fully-grown plant, for a ball at an incline, this might be sloping to rest at the bottom.

Aristotle’s description of motion was quite dissimilar from that of modern science, as his comprehension of motion was strongly linked to the actuality-potentiality concept he had developed. In simple language, he described motion as the actuality of a potentiality as such. This statement has received numerous interpretations as actuality and potentiality were opposites according to Aristotle, while some said that the addition of the word as such made it harder to understand (Barnes, 1995, pp. 40).