類實在論者（Quasi-Realism）試圖在不承認道德實在論（Moral realism）的存在論（Ontology）前提下，能夠像道德實在論者般談論道德真理。帕菲特（Derek Parfit）在其著作《論重要之事》（On What Matters）當中，對類實在論提出質疑。類實在論者試圖重新建構「道德真理」理論，但帕菲特認為他們未竟全功。類實在論若要像道德實在論者般談論道德真理，他們的「道德真理」理論必要和道德實在論的「道德真理」理論一樣，擁有解釋道德主張（moral claims）或道德判斷（moral judgments）何以夠被視為錯誤的能力，但是帕菲特指出他們建構的「道德真理」理論欠缺足夠能力去解釋為什麼道德主張或道德判斷能夠被視為錯誤。本文將採用「使真論」（Truthmaker Theory），去指出為什麼帕菲特其實誤解了類實在論者就「道德真理」的基礎（ground）所持的立場。基於類實在論者如何看「道德真理」的基礎，他們該有能力去解釋為什麼道德主張道德判斷能夠被視為錯誤。然而，為了提出合理的解釋，類實在論者不得不承認在「道德真理」和「自然事實」（natural facts）當中，必定存在一個「使之為真」的關係（truthmaking relation）。但若然類實在論者承認此關係，他們則需要面對「隨附性論證」（the argument from supervenience）的質疑。因此，本文提出一個類實在論者難以迴避的兩難－他們不能同時合理地解釋道德主張道德判斷何以能夠被視為錯誤，以及拒絕來自「隨附性論證」的質疑。
Quasi-Realists attempt to talk of moral truth in the manner of a moral realist without committing to the ontology of moral realism. In Derek Parfit's book On What Matters, he argues that they fail to do so because their constructed account of moral truth lacks an essential functional characteristic, which helps it to work like the moral truth in moral realism. That is, the account fails to possess the ability to explain why moral judgments and claims can be wrong or mistaken. In this article, I will adopt the Truthmaker Theory to demonstrate why Parfit misunderstands Quasi-Realism regarding its meta-ethical stance about the grounding of moral truth, and thus Quasi-Realism are not unable to explain why moral judgments and claims can be wrong or mistaken. However, in reply to Parfit's challenge, Quasi-Realists also need to concede that there must be a truthmaking relation between their constructed moral truth and natural facts. Thanks to this relation, I argue they need to face a possible challenge of the argument from supervenience. As a result, Quasi-Realists would face an unavoidable dilemma between explaining why moral claims can be wrong in a reasonable sense and rejecting the challenge of the argument from supervenience.
