Physical idealism

[Mudhammam]

Everything you've referred to in support of or -as- a "formal principle" is something that I would call a material object or material interaction.  

An "idea" of a thing is not the same as the materials and the arrangement from and by which an actual thing comes into being. What you two seem to disagree upon is whether or not it was the case that there were no ideas of things until there were things with ideas.