When we look at sciences such as chemistry and biology, these sciences are based on a well-defined unit of study. Chemistry studies atoms as defined by chemists and biology studies cells as defined by biologists.
Physics studies particles. But there is no well-defined definition of particle in physics. When a physicist writes the word “particle” or uses the symbol “m” standing for “mass” in an equation both are undefined. They can refer to an object which has infinite density and therefore indivisible; or they can refer to a composite object therefore divisible.
Physicists have no standard criteria to evaluate if an object is divisible or not; by default they assume that all objects they supposedly observe are “fundamental building blocks of nature”, that is, infinitely dense indivisibles.
Then, inevitably, the next generation of physicists with new colliders with higher energies prove that what the previous generation called indivisible were divisible and they call their own supposed-indivisibles the true fundamental building blocks of nature.
Physicists meticulously developed this charade into perfection and now they call anything and everything a particle. Some things physicists call particle are
and each of these have their anti-particles.
In short, physics is still a “candidate for science” but not a science because practitioners still have absolute authority to define as they wish the fundamental unit of study of their business. As long “particle” remains as casuistry in physics, physics will remain a casuistry and will be a candidate for science but not science.