James Ladyman and Don Ross's (L & R) philosophy of physics is primarily motivated by the findings of quantum mechanics. Elements of their position can be traced back to - among others - Ernst Cassirer. (Cassirer died in 1945.) Indeed L & R have much to say about Cassirer. For example, they wrote the following:
Clearly, if the penetrability argument is true and two particles may occupy the same location, then each particle can't be seen to have its own trajectory in spacetime. In other words, it will share that trajectory with other particles.
Since it's difficult to decipher whether it's a two-particle state or a single state in which two particles are interchanged, L and R adopt the “alternative metaphysical picture” which “abandons the idea that quantum particles are individuals”. Thus all we have are states. That means that the “positing individuals plus states that are forever inaccessible to them” is deemed (by L & R) to be “ontologically profligate”.