Department of Philosophy, The American University in Cairo, Egypt.
Division of the Humanities and Social Sciences, California Institute of Technology, CA, United States.
Stud Hist Philos Sci. 2023 Jun;99:10-27. doi: 10.1016/j.shpsa.2023.01.002. Epub 2023 Mar 24.
We argue that the asymmetry between diverging and converging electromagnetic waves is just one of many asymmetries in observed phenomena that can be explained by a past hypothesis and statistical postulate (together assigning probabilities to different states of matter and field in the early universe). The arrow of electromagnetic radiation is thus absorbed into a broader account of temporal asymmetries in nature. We give an accessible introduction to the problem of explaining the arrow of radiation and compare our preferred strategy for explaining the arrow to three alternatives: (i) modifying the laws of electromagnetism by adding a radiation condition requiring that electromagnetic fields always be attributable to past sources, (ii) removing electromagnetic fields and having particles interact directly with one another through retarded action-at-a-distance, (iii) adopting the Wheeler-Feynman approach and having particles interact directly through half-retarded half-advanced action-at-a-distance. In addition to the asymmetry between diverging and converging waves, we also consider the related asymmetry of radiation reaction.
我们认为，发散和汇聚电磁波之间的不对称性只是众多可通过过去假设和统计假设（共同为早期宇宙中物质和场的不同状态分配概率）来解释的观测现象中的不对称性之一。因此，电磁辐射的箭头被纳入到对自然界中时间不对称性的更广泛解释中。我们对解释辐射箭头的问题进行了通俗易懂的介绍，并将我们首选的解释箭头的策略与三种替代方案进行了比较：（i）通过添加辐射条件来修改电磁定律，该条件要求电磁场始终归因于过去的源，（ii）去除电磁场，让粒子通过延迟的远距离作用直接相互作用，（iii）采用惠勒-费曼方法，让粒子通过半延迟半先进的远距离作用直接相互作用。除了发散和汇聚波之间的不对称性外，我们还考虑了辐射反应的相关不对称性。
