Fundamental ontological distinction exists between natural things and artifacts. Natural products (animals and their parts, plants, and the four elements) move, grow, change, and reproduce themselves by inner final causes; they are driven by purposes of nature. Artifacts, formed from the human soul on the other hand, cannot reproduce themselves. Without human care and intervention, they vanish after some time by losing their artificial forms and decomposing into (natural) materials. For instance, if a wooden bed is buried, it decomposes to earth or changes back into its botanical nature by putting forth a shoot.
e.g. This fundamental difference between man-made products and natural substances continues to prove contentious within contemporary social milieu impassioned by our ever technological worldly advances. In the Middle Ages, Avicenna criticized alchemy on the ground that it can never produce ‘genuine’ substances. Even today, some still maintain that there is a difference between, for example, natural and synthetic vitamin C