“What an observer will perceive if there is superposition of a half-dead and a half-alive cat?” According to Penrose, we need a separate theory to describe our perception of Schrödinger’s cat situation in real world, which will be successful in describing the superposition of space-time geometry.
Hawking’s universe is a closed universe, where black hole evaporation is time symmetric. Penrose thought that it would be an open one. Dr. Craig pointed out that since this lecture was held in the late 90s, many things have been changed since then, especially, the prediction of lower Hubble constant has been proved to be inaccurate. He also explained that in microscopic scale,we can carry out a similar experiment as of the thought experiment on Schrödinger’s cat, and examine uncertainty of our visual perception.
Here is the BBC link of Penrose’s latest view about universe.