“The problem with all fields of research is that people are impatient. It a particular line of enquiry seems to be making progress, we continue down the line, but if it seems to be getting nowhere, we abandon it. This is a problem because the route to the future is often tortuous. Things seems to be moving towards the goal but then unexpectedly snake off in the wrong direction. Initially unproductive approaches can often turn out to be the only ones that lead to the desired destination.”