2.02331 Either a thing has properties that no other has, and then one can distinguish it straightaway from the others by means of a description, and refer to it thereby; or else there are several things that have all their properties in common, and then it is altogether impossible to pick out one of them.
Because if a thing is not distinguished by anything then I cannot distinguish it, because otherwise it really would have been distinguished all along.
All talk of external properties is dropped here in this only explanatory comment on 2.0233. Presumably, therefore, it is not that important, at least at this stage. Distinguishing one object from another is not something that we do. If a distinction can be made then it is there already. The properties of objects belong to them and cannot be added to with gifts from us. At least in this sense they are essential, i.e. necessary and unchangeable. Again this sounds metaphysical, but is in fact purely logical. The rather hypothetical status of objects is underlined by their being referred to here again by the vaguer term "thing". The vagueness is partly inherent in the word itself, and partly in the fact that Wittgenstein is not bothering to stick to one term. What I am calling a dimension is not created by adding together a bunch of points. Rather, we start with the dimension (think of a Cartesian graph) and then pick out points along it. These are Wittgenstein's objects, and they are no more real than mathematical points (which is not to say that they are utterly unreal, of course).