![physics strings theory physics strings theory](https://i5.walmartimages.com/asr/e75b96e0-5861-45d6-b8c2-221f6f8d8b98_1.b9822906e14fe7f754710349a54852dc.jpeg)
Other theoretical physicists dived in, and couldn't resist the urge to give the framework a traditional interpretation in terms of time and space and following the evolution of particles. Reviving this approach to the newfound strong nuclear force, theorists extended and developed the s-matrix idea, finding that certain mathematical functions that repeated themselves were especially powerful. It was a cool idea but proved too difficult for anybody to get excited about, and it died on the vine - until physicists got desperate in the '60s. That machine encodes all the interaction in a giant box without actually worrying about the evolution of the system. Instead, he argued, why don't we just skip all that work and develop a machine, called the scattering matrix, or s-matrix, that immediately jumps from the initial state to the final state, which is what we really want to measure. In the 1930s, Heisenberg suggested a rather extreme idea: instead of taking the normal classical physics approach of 1) write down the starting positions of all the particles involved in an interaction, 2) have a model of that interaction, and 3) follow the evolution through time of those particles, using your model to predict a result. In the early days of quantum mechanics (the first half of the 20th century), it wasn't exactly clear what would be the best mathematical approach to explain all that weirdness.