Sehrang Joo

People often think of objects teleologically. For instance, we might understand a hammer in terms of its purpose of driving in nails. But how should we understand teleological thinking in the first place? This paper separates mere teleology (simply ascribing a telos) and teleological explanation (thinking something is explained by its telos) by examining cases where an object was designed for one purpose but is now widely used for a different purpose. Across four experiments, we show that teleology judgments and teleological explanation judgments are dissociable, and identify three factors that influenced teleology judgments (and one that did not).

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.”