John Landy, my rival, ran 4:02 three or four times, and he used the phrase, “It’s like a wall.”   Now logically, I could not understand, as a physiologist, why a human being can run a mile in four minutes and two seconds, and four minutes and one second, and why somebody else won’t inevitably come along, train a little better, know that there’s a target to be beaten, and beat it.  So that was my mental approach to it. It was just fortunate for me that the pathway of record breaking, which continues in all aspects of athletics, had just reached this magical critical four minutes: four laps of one minute each, on a quarter-mile track. That was really the reason why it had conspired to become a possible barrier, physical or psychological.  It wasn’t, in my view, physical, but it did become to some extent psychological.  And it was really an example — I don’t know whether the word paradigm is correct — paradigm of human achievement in a purely athletic sense.  What limits are there to what the body can do?