Categories: Alternative conceptions
An historical notion that would now be considered an alternative conception:
"But since we are concerned with natural philosophy rather than manual arts, and are writing about natural rather than manual powers, we concentrate on aspects of gravity, levity, elastic forces, resistance of fluids, and forces of this sort, whether attractive or impulsive."
Newton lists levity as a natural power or force distinct from gravity in the Preface to his Principia.
Isaac Newton (1999) Mathematical Principles of Natural Philosophy (3rd edition, 1726): The authoritative translation (I. Bernard Cohen and Anne Whitman), University of California Press.
