they constitute a separate and specific notion

> Bolzano’s theory of collections is best interpreted as a distinct and distinctive theory of collections. (Simons 1998, p. 87).

In his previous works, Bolzano tried to define the concept of the collection as generally as possible. Problems and ambiguities arise in particular around collections containing concrete parts, as Paul Rusnock points out. These are not substantive for our purposes, as we will be dealing only with certain abstract types of collections. We will proceed from Bolzano’s quoted definition from the *Paradoxes of the Infinite.* What is important is that the parts contained in the collection are connected by a conjunction “and” and constitute a whole.

*Collections \[Inbegriff\]* can be given as a certain list, for instance “the sun, the earth and the moon, or the rose and the concept of a rose”. (§3). Collections can be also denoted by some idea $A$, which we call the collection of all $A$. (§14). Parts of the collections are different. [^5] The parts of the collections can, but need not be, arranged in some way.

*A multitude \[Menge\]*[^6] is a collection that is conceived such that the arrangement of its parts is unimportant. (§4). Bolzano 