言論檢查 (censorship) 背後的充分理由究竟為何？本文將以色情刊物為例探討此一問題。對此，女性主義者藍騰 (Rae Langton) 曾主張：只要色情刊物在此時此地(here and now)使得婦女遭到了噤聲或使得婦女臣屬於男性，這就足以使我們有充分理由查禁色情刊物了。本文將稱此一主張為「一次決定論」(once-and-for-all-ism)。然而格林 (Leslie Green) 卻不同意藍騰的主張，並認為：色情刊物無法隨時隨地使得婦女遭到噤聲或使得婦女臣屬於男性，因此我們並沒有充分理由查禁色情刊物。本文稱此一主張為「全有全無論」(all-or-none-ism)。本文將反對藍騰的「一次決定論」，並認為格林的「全有全無論」較為合理。本文將主張：藍騰的「一次決定論」由於無法避免「侵害思想自由」問題，因此並不能為言論檢查提供充分理由。

An anti-pornography feminist, Rae Langton argues that pornography may subordinate and silence women. Langton thinks that the fact that women are not subordinated or silenced by pornography, everywhere and every time, does not undermine the apparent fact that they are subordinated and silenced, here and now. To demand otherwise comes close to demanding that no women are subordinated and silenced by pornography unless all women are subordinated and silenced by pornography. Let’s call it Langton’s once-and-for-all-ism. On the other hand, Leslie Green argues that the mere fact that women might be subordinated-in-pornography or silenced-in-pornography will not suffice to bring them within the jurisdiction of pornography. Therefore, Green thinks that Langton does not show that women are subordinated or silenced by pornography. Let’s call it Green’s all-or-none-ism. In what follows I will argue that Green is right in thinking that we should not restrict pornography merely on the ground that pornography does subordinate or silence some women, here and now. Therefore, there are some powerful liberal reasons for thinking that Langton’s once-and-for-all-ism is not a good argument for censoring pornography.