Explainable machine learning models primarily justify predicted labels using either extractive rationales (i.e., subsets of input features) or free-text natural language explanations (NLEs) as abstractive justifications. While NLEs can be more comprehensive than extractive rationales, machine-generated NLEs have been shown to sometimes lack commonsense knowledge. Here, we show that commonsense knowledge can act as a bridge between extractive rationales and NLEs, rendering both types of explanations better. More precisely, we introduce a unified framework, called RExC (Rationale-Inspired Explanations with Commonsense), that (1) extracts rationales as a set of features responsible for machine predictions, (2) expands the extractive rationales using available commonsense resources, and (3) uses the expanded knowledge to generate natural language explanations. Our framework surpasses by a large margin the previous state-of-the-art in generating NLEs across five tasks in both natural language processing and vision-language understanding, with human annotators consistently rating the explanations generated by RExC to be more comprehensive, grounded in commonsense, and overall preferred compared to previous state-of-the-art models. Moreover, our work shows that commonsense-grounded explanations can enhance both task performance and rationales extraction capabilities.

介绍了一种自我合理化的框架RExC，旨在提供两种互补类型的解释（NLE和提取合理），并将其与背景知识结合起来，从而达到了任务最新水平的性能，并大幅度领先于现有模型，同时进行干扰分析表明，解释与预测之间存在高度的关联性。

基于知识的自我合理化:通过抽取和自然语言解释