Aristotle didn't really have an approach to cells. He existed around the time Democritus and others were theorizing about atoms and space, and was instrumental in playing a part in the collection of scientific knowledge. He was very detailed and contributed much in the field of anatomical dissection (animals, not humans) and was thousands of years ahead of his time in some areas. But it was not until the invention of the microscope, generally attributed to Galileo, around 1500 years later, that cells were actually viewed. The term "cell" was coined by Robert Hooke, when he was looking at a thin strip of cork. He saw what looked like lots of little boxes all stacked on top of each other, so he called them cells. A couple of years later, Schwann and Schleiden helped finalize what would be known as the cell theory.