Individuality, discernibility, and entanglement

基于对真正纠缠的深刻理解，而不是单纯的排列不变性，莱布尼茨策略一直在追求，根据该策略，即使在量子力学领域，也可以捍卫（定性）不可分辨的（数值）同一性原理的传统版本。这种方法得到了全面的发展，以便公正地对待每一种可能的物理情况，包括对称积态的玻色子。现在，重点转向语言哲学与物理形而上学的关系，特别是指称问题与对象个性的关系。由于执行的策略，张量积指标作为（直接引用的）专有名称的标准读数受到压力，但尚未确定替代方案。可能的替代方法——通过（描述性）指定、自由变量或（不可约的）指示来引用——将被详细讨论。这包括应用“使用/提及”的区别，这种区别再次出现在主动对称变换与被动对称变换的物理区别中。此外，在给定某种描述的情况下，应该调查反事实可能性的模态含义。理想论是一种有效参考物理对象的理论，它在比量子力学更广泛的范围内考虑了量子场论。不仅它们的形式主义是无标签的，而且（所谓的）粒子数物理事实中的空间离域和模糊性也与引用问题相关。

Based on the sharpened understanding of genuine entanglement as opposed to mere permutation invariance, the Leibniz-strategy has been pursued according to which a traditional version of the principle of the (numerical) identity of (qualitative) indiscernibles can be defended even in the domain of quantum mechanics. This approach has been comprehensively developed in order to do justice to every physically possible situation, bosons in symmetric product states included. Now, the focus turns on the relationship between philosophy of language and metaphysics of physics, in particular concerning the connection between the referencing-problem and the individuality of objects. Due to the performed strategy, the standard-reading of the tensor product indices as (directly referential) proper names is under pressure, but no alternative has been conclusively established. The possible alternatives – referencing via (descriptive) designations, free variables, or (irreducible) demonstratives – will be discussed in detail. This includes to apply the to-use/to-mention distinction which re-appears in the physical distinction of active versus passive symmetry transformations. Also, the modal implications of what is – given a certain description – counterfactually possible should be investigated. The desideratum is a theory of effective reference to physical objects that is broader in scope than quantum mechanics by considering also the quantum field theories. Not only is their formalism label-free, but also are spatial delocalization and vagueness in (so-called) particle number physical facts being relevant for the referencing-problem.