I think, Leo, that you are taking me into philosophical territory with which I am unacquainted. But I'll have a go at responding (although we are straying off-track and I'd like to come back to the original question at some point).
Obvious Leo wrote:The properties of matter are solely defined by the observer.
How can this be so? On what basis do you argue this? I would say that "the properties of internal representations of objects are solely defined by the observer" where by observer we mean a human subject.
These properties may or may not at any time closely approximate the true properties of the objects.
Our idea of a rock depends on the context of our evaluation of it. Is it the egg of the giant sky borne thunder dragon, is it a fragment of an igneous extrusion or is it an arrangement of molecules and constituent atoms obeying the laws of physics? At different times each is accurate, but which is closest to the true nature of rock? We may never know because all we are doing is using an organic ‘computer’ to evaluate these objects.
The object however does exist. Its properties are what they are, regardless of whether we have awareness of them.
Our internal representation and its agreed public state have their own properties. Considered thus, Einstein's quote then becomes "It is the internal mental state (theory) of the observer that determines the observer's mental state (observation)".
On the matter of wetness, we are still stuck in an entirely internal consideration. Water is not wet and its relationship to other objects does not depend on its wetness. In liquid form it just does what it does. It covers something, it flows, its molecules might find themselves within the strands of a fabric and by virtue of their properties cause the object to change its position in space or its relationship to other objects. A thing and its relationship to water is what it is regardless of any representation of that relationship as "wet".
You go on to observe that I contradict myself. I am not sure I see why you feel my statements regarding objects 'being' and internal representations are inconsistent. Objects are what they are, surely this much is uncontroversial? If all humans died tomorrow from virus, the moon would remain as it is and obey the forces that cause it to do what it does.
Our ideas about the moon and why it does what it does have been built over time and represent a publicly shared representation. Regardless of its shareability, the representation still can only be realised in the brain states of human agents (and even then it will depend on the complexity of those states which vary between human agents - some agents may still hold that it is made of cheese).
The properties of objects are theirs alone and are fixed at any point in time. The properties of internal representations can be shared (in human agents) and are not fixed at any point in time.
There is not necessarily a direct correlation between the two sets of properties. We hope there is, of course, and science and rational inquiry hope to bring the two sets to greater congruity over time. But the observer defined properties of objects do not have an independent fixed existence. They are separate from the object and fluid in nature. They are properties of mind.