The individual known for theorizing the laws of motion and gravity is Sir Isaac Newton. In the 17th century, Newton formulated his three laws of motion, which laid the groundwork for classical mechanics. His work "Philosophiæ Naturalis Principia Mathematica," published in 1687, also introduced the universal law of gravitation. Newton's groundbreaking theories revolutionized the understanding of physics and mathematics, influencing countless fields and paving the way for advancements in science.