One very important genus of complex ideas that we encounter everywhere are those in which the idea of collection (Inbegriff) appears. There are many types of the latter […] I must first determine with more precision the concept I associate with the word collection. I use this word in the same sense as it is used in the common usage and thus understand by a collection of certain things exactly the same as what one would express by the words: a combination (Verbindung) or association (Vereinigung) of these things, a gathering (Zusammensein) of the latter, a whole (Ganzes) in which they occur as parts (Teile). Hence the mere idea of a collection does not allow us to determine in which order and sequence the things that are put together appear or, indeed, whether there is or can be such an order. […] A collection, it seems to me, is nothing other than something complex (das Zusammengesetztheit hat). (1837, §82, 393)