In effect, Aristotle created science as a field of study. Aristotle's founding of science stemmed from his dissent from Plato about philosophical thought. He argued that philosophy also should include observations of the natural world.
Aristotle began a school for the study of science and developed a method of scientific study that involved both observation and deduction. Aristotle's method worked somewhat backwards, beginning with an illogical conclusion.
Aristotle's focus on nature led to many sound conclusions about the natural existing world. He dissected numerous plants and animals to determine how they fit into the scheme of nature; he wrote extensively and descriptively of his findings. Aristotle concluded that every plant and animal had four common attributes: matter, form, moving cause and final cause. Matter is the raw material of which something is constructed. Form is the appearance of the final product. Moving cause is what gives something its shape. Final cause is the purpose that the item serves within the world.
Nearly 2,000 years after Aristotle died, Galileo established that Aristotle's keen powers of observation did not extend as well to the field of physics. Ironically, Galileo used Aristotle's own method to highlight the flaws in Aristotle's ideas about physics.