Discussion on answer by Dikran Marsupial: Is an “immaterial being” any less nonsensical than a “smelly color”?

I think that the big lesson here is that humans can imagine just about anything; so imagination should not be taken as a starting point for what is physically observable.

Good answer! I’m not sure if your examples work here though. Synaesthesia occurs when one sensory pathway activates at the same time as another. So it would be moreso that a color experience can occur at the same time as a smell experience, not that the “color” itself smells. Secondly, your rock example would then not be a rock. Something looking like a rock doesn’t make it a rock. Lastly, I’m curious as to how you can imagine an immaterial being. How do you imagine the being part?

Colors correspond to frequencies of visual light, smells to combinations of chemicals. The fact that some people's sense are miswired, so their vision sends signals to the olfactory cortex doesn't mean the colors are actually smelly -- these are misperceptions due to a disorder.