本文針對猥褻言論和從娼賣淫提出一種自由主義的立場。這個立 場有別於完全禁止的保守派，也有別於完全開放的放任自由派。本文 認為，自由主義反對政府完全禁止個人散播猥褻言論，但自由主義並 不反對，政府基於平等保護個人的性自主可以禁止個人從娼賣淫。本 文詳細剖析了自由主義的正當性原則，主張正當性原則具有兩部分： (1)政治決定或政治權力的行使，就後果而言，必須有利於（或至少 沒有不利於）公民去施展他們的價值觀能力；（2)政治決定或政治 權力的行使，就理由或根據而言，必須充分，但不得訴諸任何會引起 合理爭議的終極價值觀（中立性原則）。本文在這項原則的基礎上， 透過分析言論自由的内涵以及性自由與性自主之區別，反駁了保守派 與放任自由派的論點。

This essay is an attempt to defend a liberal position with respect to pornography and prostitution. It argues against both conservatives and libertarians. Its main claims are that to respect freedom of speech, the state may regulate pornography, but should not prohibit pornography, and that in order to provide equal protection of sexual autonomy for all, the state may ban prostitution. Its main arguments are based on a liberal principle of legitimacy, which consists of two parts: (1) the state should ensure the favorable conditions for its citizens to develop and exercise their capacity for a conception of the good; and (2) the state should be neutral with respect to controversial conceptions of the good when it exercises its powers.