The most widely accepted analysis of the word order optionality in many languages assumes that the movement operation of scrambling is responsible for the optionality(Saito 1992, Hoji 1985, Tada 1993, Fukui 1993). According to this analysis, scarmbling is claimed to ⅰ) be strictly optional and ⅱ)be simantically vacuous. In this paper I gave two pieces of evidence for the claim ⅰ), interpreting the optional movement as the movement not driven by any morphological features. The first evidence comes from the island facts and the second one is from the reconstruction facts. As for the semantic vacuity of scrambling in ⅱ), I argued that scrambling can be semantically effective, depending on which sites the scrambled phrases can be reconstructed to.