"If knowing is to be possible as a way of determining the nature of the present-at-hand by observing it, then there must first be a deficiency in our having-to-do with the world concernfully. When concern holds back from any kind of producing, manipulating and the like, it puts itself into what is now the sole remaining mode of Being-in, the mode of just tarrying-alongside. In this kind of 'dwelling' as a holding-oneself-back from any manipulation or utilization, the perception of the present-at-hand is consummated.

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— Martin Heidegger