4 ideas
In late 1879 Edison's Menlo Park team tested thousands of filament materials, including platinum, carbonized paper, cotton thread and later bamboo. They were hunting for one that would glow in a high vacuum without burning out.
Edison set up Menlo Park to produce inventions on schedule, not to wait for discoveries. It was known for his stated goal of 'a minor invention every ten days and a big thing every six months or so.' He gathered machinists, glassblowers, chemists and a well-stocked supply room under one roof, so that any idea could be built and tested within hours. This turned invention from lone inspiration into a repeatable industrial process.
The light bulb was commercially worthless on its own. Edison designed the generators, wiring, meters, fuses and the Pearl Street central station alongside it, and set the bulb's high resistance to fit an economical distribution network. An invention succeeds when it is designed backward from the full infrastructure and cost structure it must live inside.
Edison treated each failed experiment as data that shrank the search space. Seen this way, a long run of negative results is a sign of progress through a finite field of options, so persistence becomes a rational search strategy rather than stubbornness. The War of the Currents shows the limit of this lens: loyalty to DC led Edison to fight AC with fear campaigns instead of treating the evidence against DC the same way.