Time Tools.

Many core human activities require an understanding of time. To coordinate rituals, plan harvests and hunts, recall histories, keep appointments, and follow recipes, we need to grapple with invisible temporal structures like durations, sequences, and cycles. No other species seems to do this. But it is not a capacity we humans have because we developed special neural equipment over biological evolution. We have it because we developed concepts, practices, and artifacts to help us-in short, because we developed time tools. The overarching function of such tools is that they render time more concrete: they identify structure in the flow of experience and make that structure available to the senses. By concretizing time in this way, these tools serve a range of practical purposes, from tallying and measuring, to coordinating and predicting, to remembering and reasoning. Beyond their practical utility, time tools have further consequences, too: they reverberate through cognition and culture, and ultimately reshape our understanding of what time is.