In this paper, I demonstrate that a well-known left-right asymmetry, Biberauer, Holmberg and Roberts’s (2014) Final-over-Final Condition (FOFC), which these authors claim follows from Kayne’s Linear Correspondence Axiom (LCA), is actually better explained under a symmetric approach to syntactic structure building in tandem with the mechanism that underlies the constraints on rightward movement. Apart from circumventing the theoretical and empirical problems that this LCA-based analysis faces, the fact that particles form a natural class of counterexamples to FOFC naturally follows under such a symmetric approach. The final part of this paper shows that this explanation to FOFC also straightforwardly applies to the semi-universal leftwardness of (subject) specifiers in both head-final and head-initial languages.

在本文中，我证明了众所周知的左右不对称性，Biberauer、Holmberg 和 Roberts（2014 年）的最终条件（FOFC），这些作者声称该条件源自凯恩的线性对应公理（LCA），实际上是更好地解释了一种对称的句法结构构建方法，以及限制向右移动的机制。除了规避这种基于 LCA 的分析所面临的理论和经验问题外，粒子形成 FOFC 的自然反例类这一事实自然地遵循这种对称方法。本文的最后部分表明，对 FOFC 的这种解释也直接适用于头尾语言和头首语言中（主语）说明符的半普遍左倾。