Experiments have led some philosophers to conclude that the reference determination of natural kind terms is neither simply descriptive nor simply causal-historical. Various theories have been aired to account for this, including ambiguity, hybrid, and different-idiolects theories. Devitt and Porter (2021) hypothesized that some terms are covered by one theory, some another, with a place for all the proposed theories. The present paper tests hypotheses that the term ‘Rio de Janeiro Myrtle’ is simply causal-historical but the term ‘rice’ is hybrid. For, whereas the former term is of scientific but little practical interest, the latter is not: rice is a significant part of the human diet. So, we predicted there would be two factors to the reference determination of ‘rice’: a superficial-descriptive one and a deep-causal one. Our experiments confirmed these hypotheses using the methods of elicited production and truth value judgments. We take our results to support the hybrid Theory of ‘rice’ rather than the ambiguity or different-idiolects theory. We were not testing ‘myrtle’ but, surprisingly, our results implied that ‘myrtle’ was partly descriptive and so like ‘rice’ but not ‘Rio de Janeiro Myrtle’. A follow-up experiment confirmed these puzzling results. More investigation is needed.

中文翻译：

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两种生物类术语：“大米”和“里约热内卢香桃木”的案例

一些哲学家通过实验得出结论，自然类项的参照确定既不是简单的描述性的，也不是简单的因果历史性的。人们提出了各种理论来解释这一点，包括歧义理论、混合理论和不同语言理论。 Devitt 和 Porter (2021) 假设，某些术语由一种理论涵盖，另一些术语由另一种理论涵盖，所有提出的理论都有一席之地。本文测试了以下假设：术语“里约热内卢桃金娘”只是因果历史性的，而术语“大米”是混合的。因为，前一个术语具有科学意义，但没有什么实际意义，而后者则不然：大米是人类饮食的重要组成部分。因此，我们预测“大米”的参考判定将有两个因素：一是表面描述性因素，二是深层因果性因素。我们的实验使用引发产生式和真值判断的方法证实了这些假设。我们的结果支持“大米”的混合理论，而不是歧义或不同方言理论。我们没有测试“桃金娘”，但令人惊讶的是，我们的结果表明“桃金娘”具有部分描述性，因此类似于“大米”，但与“里约热内卢桃金娘”不同。后续实验证实了这些令人费解的结果。需要更多调查。