Astronomical observations are successively refined to be exact to tenths, to hundredths, and to thousandths of seconds.

But the final refinements are arrived at by a system of averaging, and even then present us with a stretch of time as a margin of error.

Here error is merely a conventional term to express the fact that the character of experience does not accord with the ideal of thought.

I have already explained how the concept of a moment conciliates the observed fact with this ideal; namely, there is a limiting simplicity in the quantitative expression of the properties of durations, which is arrived at by considering any one of the abstractive sets included in the moment.

In other words the extrinsic character of the moment as an aggregate of durations has associated with it the intrinsic character of the moment which is the limiting expression of natural properties.
Thus the character of a moment and the ideal of exactness which it enshrines do not in any way weaken the position that the ultimate terminus of awareness is a duration with temporal thickness.