What's more complicated than theoretical physics?
It's not a trick question. Superstar scientist Stephen Hawking has theorised extensively about black holes and how the universe works, but he's still left utterly stumped by one fact of life - the popularity of Donald Trump.
When asked to explain the rise of support for Trump, appearing on ITV's Good Morning Britain the esteemed scientist said: "I can't".
“He is a demagogue, who seems to appeal to the lowest common denominator,” he added.
Hawking also warned that Brexit would put the country at risk of recession.
He said the two reasons for staying in Europe were the mobility of people, particularly students, and collaboration on ideas.
"The first is that it promotes the mobility of people. Students can come here from EU countries to study, and our students can go to other EU universities. More importantly, at the level of research, the exchange of people enables skills to transfer more quickly, and brings new people with different ideas, derived from their different backgrounds,” he said.
"Without this exchange, we would become more culturally isolated and insular and ultimately more remote from where progress is being made."
The second reason he gave was financial, with the EU giving grants for research and warning that British institutions were increasingly being starved of homegrown funding.
He said UK research institutions seemed to be becoming "progressively starved of resources by a government intent on short term cuts, without attention to longer term consequences."