"When you take those and you look at the world from that lens, you can identify structural changes that are multi-year in nature, not something kitschy and short."
He says good funds are constantly updated to reflect the changing landscape, for instance to replace holdings in line with the theme.
“We're not traders, but you need to be an active investor," he says.
"You need to constantly check the data points, whether it's from consumers, whether it's from surveys, whether it's from a company's customers, competitors, suppliers, because you have to constantly monitor the data points to confirm that whatever investment thesis you have continues to play out.
"So we do that every six months, we try to have high thematic purity, saying at least 80 per cent of revenue or profits are generated by the theme. But are there opportunities for newer technologies to displace competing ones? - the answer is yes."
He adds: “It's understandable that a lot of people are pouring into thematics with solutions, but not all solutions are created equal.
"And I think that's where the rubber will hit the road over time that these well crafted well thought out strategies will continue to ring true over over the coming 12, 18, 24 or 36 months.”
carmen.reichman@ft.com