It may be a slight exaggeration to claim that Isaac Newton alone laid the foundations for modern physics. But only a slight one. His work is full of innovative ideas that, to begin with, were as incomprehensible for his contemporaries as they are indispensable for scientists today. Take the idea of a force that acts across empty space. Newton formulated the force of gravity as just such a force, and his contemporaries had great difficulty with this; they couldn't imagine that a force could act “just like that,” without there being any material contact between the objects involved. It seemed like magic, and even Newton wasn't completely sure whether some divine intervention was perhaps necessary after all to convey the force of gravity.

As in so many cases, this idea of Newton's proved to be a fruitful starting point for further research. Modern physics has solved the problem of forces acting “just like that” by showing that there are fields of force. An object can create a field around itself that spreads out and influences other objects. The force of gravity can be exerted in this way, as can other forces like electricity or magnetism. The mastery and manipulation of electrical and magnetic fields form the basis of our modern technology, but even the fundamental characteristics of matter itself are explained by fields in physics today. Quantum field theory defines particles as the agitation of fields: photons, i.e., light particles, arise from the agitation of electromagnetic fields. Other particles are created out of their own particle fields; the so-called standard model of particle physics explains the interaction between all of these fields.

Isaac Newton also took the first step toward another major project of modern science: the unification of all forces acting in nature. His law of universal gravitation showed that completely different phenomena in the sky and on the earth can be explained by a single force. If we just observe the world in the right way, the differences disappear and everything appears much simpler and more elegant than before. In the nineteenth century, the Scottish physicist James Clerk Maxwell demonstrated that electricity and magnetism are also not two isolated phenomena, but are merely two different ways in which the unified force of electromagnetism can be exerted. Albert Einstein spent the last decades of his scientific career trying to find a way to bring electromagnetism and gravity together. Here, too, in a sense, he was following Newton's directions. In the book Opticks, Newton wonders: “Are not gross Bodies and Light convertible into one another, and may not Bodies receive much of their Activity from the Particles of Light which enter their Composition?” That almost sounds a bit like Einstein's most famous formula (E = mc^²), which demonstrates how matter and energy can be converted into one another. Einstein didn't manage to achieve a complete unification of the forces of mass and light, however, and the researchers who have followed him have also not yet succeeded in merging all forces known in nature into a single theory. Centuries ago, Isaac Newton took the first step toward a universal unification in physics, and every new generation since then has taken a small step further along this path. How long the path will be cannot yet be said; the search for the explanation of the universe that the media likes to call the “theory of everything” is not yet over.

In the seventeenth century, Isaac Newton provided the world with a research program on which the whole of science is still working just as intensively today as he did back then on his own. He was an eccentric, an egoist, a troublemaker, and a mystery-monger. He tolerated no criticism and was uncompromising, vengeful, and conniving. But he was also the greatest genius ever to have lived. No other scientist has had such an important, wide-ranging, and enduring influence on the entire world as he did. Sometimes, it would seem, if you want to change the world, you have to be both a genius and an asshole.