Many notes must be added to the slip box before it is really useful, as Luhmann himself notes (Luhmann, 2015a):
The slip box needs a number of years in order to reach critical mass. Until then, it functions as a mere container from which we can retrieve what we put in.
Still, one must start somewhere, even if it is useless (Luhmann, 2015b):
This leads to another question: what are we to do with what we have written down? Certainly, at first we will produce mostly garbage. But we have been educated to expect something useful from our activities and soon lose confidence if nothing useful seems to result. We should therefore reflect on whether and how we arrange our notes so that they are available for later access. At least this should be a consoling illusion.
This problem is not unique to the slip box. Le Clerc indicates, in his introduction to Locke's method of making a common-place book (Locke, 1706):
At the Entrance indeed upon any Study, when the Judgment is not sufficiently confirm'd, nor the Stock of Knowedge over large, so that the Students are not very well acquainted with what is worth Collecting, scarce any Thing is Extracted, but what will be useful but for a little while; because as the Judgment grows Ripe, those Things are despis'd which before were had in esteem. Yet it is of Service to have Collections of this Kind, both that Students may learn the Art of putting Things in Order, as also the better retain what they Read.