Do you accept that thought has a physical basis? Aren't ideas a form of thought?
I believe that thoughts manifest as electrical activity in the brain. The act of thinking can be tracked by PET scans and such.
A Idea is the result of thought. It has no physical properties as such. Just as words written on paper or a computer do not have physical properties. Words and language have content but do not hold a physical address. imo.
Without any physical brains with which to have thoughts do ideas exist?
No. If every human brain on the planet ceased to exist so too would all novel ideas. However the ideas stored in literature and on computers would still exist until such a time as the media/medium is destroyed.imo. If Cephalopods someday inherited the Earth and became literate,or if some alien culture found our stored ideas then they would once again exist.
Does the idea still exist? Or did the idea kick the bucket along with my physical brain?
The idea ceases to exist along with the brain that processes and stores it.imo.
No.........................in order to witness "branes" and new universes being "created" one would have to be outside all frames of reference. Being apart from all frames of reference leaves no perspective. Quantum mechanics shows that reality is quantized and exist in descreet packets of information. observation acutalizes the collapse of the wave fucntion and outcomes being manifested. Reality refuses to be curtailed to a set. In other words it is a mystery as of yet. Such thought experiments are like asking, "where in the universe is the universe?" imo
"Outside all frames of reference" is an interesting idea. Do you mean like a timeless, immaterial realm? But why can't such a realm have its own frame of reference?
Things happen because there is a degree of inequalities in the universe. Thermodynamics is the process that allows systems to achieve homeostasis through the exchange of energy states.
If everything was in homeostasis and delta s= zero. how could there be any change? No time and space and matter is for all intensive purposes moot. For there to be a "nothing" there must be NO THING. Subtracting ones existence from the equation at least in this reality is impossible as Quantum mechanics shows a observer/measurement is somehow linked to the outcome. We can try to imagine anything we want. But we can't know without looking into the box.