Aristotle contributed to modern atomic theory by introducing alchemy, an ideology that chemists eventually rebelled against. Aristotle argued alchemy above observation and scientific research. His beliefs held that the world was made of elements endlessly divisible.
Many chemists and philosophers argued Aristotle and believed in atomic theory. Democritus consistently challenged Aristotle and insisted that the elements were made of a variety of shapes and sizes. He also believed that this is what gave the different elements their attributes. The notion that the atom is an element broken down to its smallest proportion was in complete opposition to Aristotle's beliefs. Instead, Alchemy, held that a God, or gods, could divide an element infinitely.
Chemists, such as Robert Boyle, began to take a skeptical perspective to Aristotle's approach. Skepticism lead to many scientific discoveries that were based on fact. Other scientists such as John Dalton were also proving the existence of atoms by demonstrating his theories with handmade models.
Alchemy practices still exist. Atomic theory, and modern science, are born out of mankind's continual determination to strive for the truth and to continue questioning established theories. This fundamental aspect of science keeps mankind in a continual state of learning and making technological breakthroughs to advance modern society.