According to the Lankavatara Sutra (Suzuki’s translation) “the world appears to exist, but nothing is really existing.” This is true from the standpoint of Mind itself, the absolute substance.
I know I have mentioned this before, but in the example of a clay pot or an elephant carved from wood, neither the pot nor the elephant exist apart from the clay or the wood. And so it goes from the standpoint of absolute Mind. The world we observe is a phenomenalization of Mind. This becomes absolutely true for us when we realize Mind for the first time. Until that time, we have to believe that what the Buddha is teaching us is true. Nothing is really existing as if it were existing apart or separate from Mind itself.
This brings me to another point—a very important point. We have to have a real intuition of pure Mind. This, I need to add, is what separates Buddhism from metaphysical and religious speculation. Buddhists don’t have time to argue with some idiot philosopher or religionist who believes that Mind is not the absolute substance. The Buddhist has attained the proper gnosis of pure Mind—the philosopher or the religionist is deluded just plain crazy.