Sehrang Joo

People may conceptualize certain categories as held together by a category-specific “essence”—some unobservable, critical feature that causes the external features of a category to emerge. But what is the nature of this essence? Recently, Rose and Nichols have argued that something's essence is fundamentally its telos or purpose. However, Neufeld has challenged this work on theoretical grounds, arguing that these effects arise only because people infer an underlying internal change when reasoning about a change in telos. In Neufeld's view, it is the underlying internal cause, and not the telos itself, that serves as an essence (consistent with classic views of scientific essentialism). Here, we ask: Is teleology the primary force behind psychological essentialism? We begin by successfully replicating Rose and Nichols’ key findings in support of teleological essentialism. In two further experiments, however, we demonstrate that teleology may not be the central way that people understand the essences of living things. We show that internal changes matter at least as much as changes in teleology. These findings suggest that while teleology may be one important cue to category membership and the essences of living things, it may be premature to say that we are “teleologically essentialist.”

People often think of and define objects teleologically. For instance, we might understand a hammer in terms of its purpose of driving in nails. Such teleological thinking also influences many further judgments, including of category membership, essence, causation, persistence, and mereology. But how should we understand teleological thinking in the first place? This paper addresses this question by separating two senses of teleological thinking: mere teleology (simply ascribing a telos to an object) and teleological explanation (thinking an object is actually explained by its telos). Experiment 1 examined cases where an object was designed for one purpose but is now widely used for a different purpose, and found that teleology judgments and teleological explanation judgments are dissociable: Only an artifact’s original purpose could serve as an explanation, but its new purpose could also be its telos. Experiments 2-3 sought to break down these factors that were sufficient for mere teleology; three factors other than creator’s intentions influenced teleology judgments: present use, collective recognition, and success at a function. Finally, Experiment 4 identified one factor that did not affect mere teleology: structure-function fit. Implications for work on object teleology and interpretations of teleological reasoning more generally are discussed.