The author is talking about how a given physics model appears simple when they are presented with it, e.g. a particular quantum field theory. This is the kind of limited perspective about research that an undergraduate physicist may develop simply by solving the hand crafted problems that are presented to them.
However, the true difficulty in physics is arriving at that model in the first place. Decades of work offered up against experiment, the associated conceptual leaps in understanding required to get to e.g. a quantum field theory which succesfully predicts things are nothing short of a monumental achievement. To say that physics is simple is ludicrous.
However, the true difficulty in physics is arriving at that model in the first place. Decades of work offered up against experiment, the associated conceptual leaps in understanding required to get to e.g. a quantum field theory which succesfully predicts things are nothing short of a monumental achievement. To say that physics is simple is ludicrous.