Is the imaginary time just a different convention to express the time evolution to make the calculations easier? Hawking also said that
"It turns out that a mathematical model involving imaginary time predicts not only effects we have already observed but also effects we have not been able to measure yet nevertheless believe in for other reasons." (From "The Universe In a Nutshell", UK, Bantam, 2001 edition, page 59, last paragraph.)
What are the predictions that we haven't been able to measure yet?