It never sat well with Arthur when people lumped his ideas into the "LSD school." But he knew there was value to slow running and problems with running too hard. So his comments about this were inconsistent. He would tell you that you can get as fit doing slow distance runs as by doing faster ones but that the former takes longer. So there was, "What the LSD runner will do in two years we can do in maybe one." There was "Good runners rarely run slower than 7:00 miles."
He'd sometimes use that as a launching pad for a story about three Aussies, Trevor Vincent, Tony Cook, and Ron Clarke saying that Cook and Vincent started doing Lydiard style distance work at around 7:00 pace and Ron Clarke started running with them at 7;00 pace when he began running again in 1961. But as Ron got fitter he quickened his pace while Vincent and Cook kept to 7:00 miles and became a multiple world record holder while Cook and Vincent "went nowhere." Aside from being very inaccurate, the story illustrates Arthur's idea of pace for distance runs; let it come to you but don't force it. Clarke was probably working no harder in, say, 1965, when he was banging out 10-12 miles in his hour's run than when he was running 9 miles or so in that time a few years earlier. There is no need to lock yourself into a particular pace for your distance runs. Run slowly enough to cover a lot of miles and when and if you can cover those miles faster do it.
In one of his later books you get a line like, "You can never run too slowly, but you can run too fast" which certainly does not reconcile with Vincent and Cook going "nowhere" by keeping to their 7:00 miles, which they actually did not do anymore than they went nowhere. On his last tour of the US he told Joe Henderson, "My runners ran as fast as they could without breathing hard." That's as good a summary as you can get and it conveys the idea he wanted in that circumstance ( talking to the guy who did more to popularize the idea of training slowly than anyone.) But in another situation, wanting to make a different point, he may well have said, "My runners ran as slowly as they needed to to avoid getting out of breath." The ONLY thing he ever said to me about pace was, "Enjoy yourself."