Their relations to each other are also characterised by a certain simplicity and uniformity.

Finally the characters of the observed physical objects and sense-objects can be expressed in terms of these scientific objects.

In fact the whole point of the search for scientific objects is the endeavour to obtain this simple expression of the characters of events.
These scientific objects are not themselves merely formulae for calculation; because formulae must refer to things in nature, and the scientific objects are the things in nature to which the formulae refer.
A scientific object such as a definite electron is a systematic correlation of the characters of all events throughout all nature.

It is an aspect of the systematic character of nature.

The electron is not merely where its charge is.