Placebo ergo sum = You hallucinate yourself into being.

I used to hallucinate as a child by pressing my hands against both closed eyelids, pressing firmly against my eyeballs. I would start to see geometric patterns and gears moving and bright spots, etc. You see what you want to make your body see. I would submit the actual visual process is rational hallucination, by which you envision objects in the distance when they are really occurring in your headspace and on your retina. Take for an example a tree, when you look at a tree, you probably dont think much about it, because you have a category in your head to store it in unconsciously. You look at a tree, and your nervous system transforms the photonic (light) information into a coherent visual image. The concept of a tree is constructed by humans. I guarantee a tree doesn't know it is a tree. It is instead a pulsing quantum collaboration of organized systems functioning on the same organismal level- the same as us humans, accept we learn to conceive and define ourselves and reality- therefore we solidify our hallucinations as an objective reality that everyone shares.

But reality is the endless muse. The tree is there, yes, but the experience of the tree depends on your state of consciousness. An ant would have different experience than a human, a treehugger would have a different experience than a arborist or a logger.