You can sort and sort and sort, and you can find all sorts of stats, but if you really tighten up your search, you will see that there have been 6 seasons in the history of the NBA that really stand out statistically.
(If you start looking for seasons with PER over 31, you get Jordan, Wilt and LeBron only, ten seasons total - a person looking for an answer for "best NBA player ever " might well find that list of 10 seasons and conclude that those are your 3 best guys....and I think that is a reasonable assumption).
Durant is current over 29 in PER, .307 WS/48 and looking hard at 20 Win Shares overall
James - 31.2, .304, also looking at 20 WS overall.
So, assuming these guys maintain this torrid pace (which seems tough to imagine, but I guess it is possible), we may see a situation where we have two guys register top 8 all-time seasons IN THE SAME YEAR.
While two such monster seasons have never occurred together, in recent history there have been two almost-as-great statistical seasons by different guys in the same year twice - in 1995-96 Jordan received 98% of the MVP vote but David Robsinon finished second and had an unbelievable statistical season (PER over 29, almost 20 win shares); and in 2008-09, James's historically great season left poor Chris Paul with no love whatsoever -- James finished first in the MVP balloting while Paul (30 PER, .292 WS/48, over 18 win shares) placed a pathetic 5th, behind Kobe, Wade and Dwight Howard.
If you are paying attention in 2012-13, NBA fans, you are witnessing history in the making.