The idea has been somewhat famously illustrated in the concept of the muse, an external entity or influence that is the actual source of the ideas that we then channel into our reality
Similar also to what Michelangelo once said:
> The sculpture is already complete within the marble block, before I start my work. It is already there, I just have to chisel away the superfluous material.
On a similar vein of the “not in the brain” concept, there are many proponents of the “embodied” consciousness, meaning that consciousness is in the whole body, not just our brain/nervous system (this is also very briefly touched upon in one episode of the AppleTV series Extrapolations)
Quote Investigator has located no substantive evidence that Michelangelo or any other great sculptor made this remark. A comment of this type was published in 1858 in “The Methodist Quarterly Review” without any overt humor. The essay discussed poetry, and the author compared the methods of adroit sculptors and poets.
I think it was Terrence McKenna who described the brain as an antenna that tunes in to a certain band of the universal consciousness, and that's what we consider to be the thoughts of an individual.
More or less same idea, slightly different way of phrasing it.
I believe some buddhist practitioners also have a similar way of thinking.
He said he believes less and less that consciousness is in the brain. Maybe it's something external, shared, and our brains work more like a camera, and make whatever is out there our own.
It made an impression on me.