My countersuggestion, issuing essentially from Carnap's doctrine of the physical world in the Aufbau, is that our statements about the external world face the tribunal of sense experience not individually but only as a corporate body.
Certain statements, though about physical objects and not sense experience, seem peculiarly germane to sense experience -- and in a selective way: some statements to some experiences, others to others.
The latter statements may be thought of as relatively centrally located within the total network, meaning merely that little preferential connection with any particular sense data obtrudes itself.
Objects at the atomic level and beyond are posited to make the laws of macroscopic objects, and ultimately the laws of experience, simpler and more manageable; and we need not expect or demand full definition of atomic and subatomic entities in terms of macroscopic ones, any more than definition of macroscopic things in terms of sense data.
Science is a continuation of common sense, and it continues the common-sense expedient of swelling ontology to simplify theory.
Epistemologically these are myths on the same footing with physical objects and gods, neither better nor worse except for differences in the degree to which they expedite our dealings with sense experiences.
Rules are arbitrary in the sense that they are not responsible to some sort of reality-they are not similar to natural laws; nor are they responsible to some meaning the word already has. If someone says the rules of negation are not arbitrary because negation could not be such that ~~p =~p, all that could be meant is that the latter rule would not correspond to the English word "negation".
In what sense are laws of inference laws of thought?
A cause could not be included in this sense.
In some cases it is senseless to ask "Which circle?", though "What sort of circle is in the square-a red one?, a large one?" may make sense.