He saw in four dimensions: Pioneering mathematician Harmann Minkowski
When I was a teenager I asked my physics teacher why things travelled in a straight line unless acted on by outside forces, intending to inspire a discussion with this dull man. His inane response, "That's Newton's First Law," convinced me the case was hopeless, but I tried. I pointed to Mach's Principle that inertial mass and gravitational mass were equal (a body's resistance to a push is proportional to its weight). I pointed to the gravitational curvature of space-time in general relativity, but all to no avail. He wasn't interested. Newton had made the laws, and he was teaching them and their consequences.
Newton was indeed a man of astonishing genius, well expressed in Alexander Pope's epigram:
Nature and nature's laws lay hid in night;
God said "Let Newton be" and all was light.
But he had not designed the universe. His laws were empirical, based on results produced by people such as Galileo and Kepler, and he followed them up by inventing the mathematics to create what we call Newtonian mechanics. It reigned supreme until the late 19th century when new observations led to two new theories. One was the fact that small amounts of radiation seemed to be given off in tiny discrete quanta of energy — this led to quantum theory. The other was that bodies travelling very fast relative to one another seemed to measure time at different rates, and the Michelson-Morley experiment of 1887 showed that no matter what your velocity, light always went past you at the same speed. You couldn't even begin to catch up with it. This led to Einstein's relativity theory.
Yet in September researchers at CERN (the European Organisation for Nuclear Research) apparently clocked neutrinos — subatomic particles that barely interact with ordinary matter — at slightly more than the speed of light. If this result can be replicated elsewhere, does it undermine the current bedrock of physics, or is there another explanation? To provide an answer, let's look at the history of relativity.