 Grosseteste’s theory of unequal infinities served as the basis of a theory of how God measured the world he created.  Grosseteste takes up measurement in his commentary on the Physics (Dales 1963a, 90–95), in one of the earliest theoretical discussions of measurement in the middle ages. He points out that human measurement of time involves taking some recurring movement—say, the daily movement of the heaven—and stipulating its duration to be a unit of measurement. In the same way, the magnitude of some body is taken as a unit of the measurement of spatial magnitude. Measurement of this sort, Grosseteste holds, is inherently relative in nature. To say that an event lasts for a day, for example, is simply to relate its duration to the duration of the movement of the heavens. But Grosseteste thought that this mode of measurement would not suffice for God, who, as he frequently mentions, “has disposed all things in number, weight and measure” (Wisdom 11: 21).  God’s creative activity requires that he create bodies with a definite magnitude and movements with a definite duration, and this requires that there be a non-relative measure intrinsic to magnitudes and durations.  According to Grosseteste, this measure is provided by the different-sized infinities of indivisibles comprising spatial and temporal magnitudes. Grosseteste points out in his commentary on the Physics that were only a single line to exist, it would not be possible for us to measure its magnitude, and yet God could do so by counting the infinite number of points that comprise its magnitude. Only God can measure in this way, for only to him is the infinite finite, an allusion to Augustine’s teaching in The City of God 20.19 that God alone can embrace an infinity in his mind.