After a theory accurately predicts experiment outcomes and an equation describes variables mathematically, it becomes a powerful tool for exploring different variable values.
However, this can become a problem.
Once a theory becomes widely accepted, there is little doubt about the validity of the equations. These equations define the variables for technical applications of the phenomena, leading to the creation of practical technological devices. Repeating all the assumptions made in developing the original mathematical equation is unnecessary. Engineers are responsible for studying and implementing the practical applications of this knowledge, constructing machines, devices, ships, and infrastructure like roads and dikes.
Engineers understand that they have limited control over operational conditions. During the development phase, a set of specifications describes the expected performance and the conditions under which it is expected. Engineers also know that their creations will eventually degrade and fail. They specify the proper use and training for the operator, who maintains usability through the repair and replacement of parts and components until maintenance becomes too costly. Engineers must always anticipate degrading conditions during use.
In particle physics, we have made progress by studying fundamental particles in a way opposite to what we might expect. Instead of starting with individual particles, we attempt to break down atoms and nuclei using complex proton smashing machines. This is because composite particles are incredibly stable, and we need advanced methods to study them.
Wikipedia:
In particle physics, an elementary particle or fundamental particle is a particle whose substructure (domain of the bigger structure which shares the similar characteristics of the domain) is unknown. Thus it is unknown whether it is composed of other particles. Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are “matter particles” and “antimatter particles,” as well as the fundamental bosons (gauge bosons and Higgs boson), which generally are “force particles” that mediate interactions among fermions. A particle containing two or more elementary particles is a composite particle.
It’s fascinating that certain particles are still uncertain whether they are composite or elementary particles. We understand that protons and neutrons are composite particles, but breaking them apart is incredibly challenging as they seem almost indestructible. Certain components, such as the electron, are considered fundamental because we can’t imagine a substructure existing, especially considering the phenomena attributed to an electron, such as electric charge. Some scientists nowadays argue that we should consider modeling the electron as a type of cloud. If we do this, we need to clearly state the underlying assumptions being made when discussing the electron, whether it is being treated as a point particle or a cloud or something else.
Unfortunately, the assumption that the electron is a point particle has been widely accepted without further clarification.