The Phillies are now at an even .400 winning percentage on the season, with 46 wins and 69 losses. The last time a Phillies team finished below .400 was the 1972 squad of the fabled Steve Carlton 27-10 season. That team finished at .378, 59-97 in only 156 games (the season began a week and a half late due to a players' strike).
Based simply on their entire season to date, the Phils are now on pace to lose 97 games, so their second half surge has all but erased the possibility of breaking the all-time franchise loss record of 111 (by the 1941 team), and even made it much less likely that they will become the first Phillies team in 54 years to lose 100 (1961, 47-107).
In order to avoid losing 100 games they now need to go at least 17-30 (.362) in their last 47. Based on their recent much improved play, that should be quite doable.
At the other end of the spectrum of scenarios for what remains of the season, their hot start to the second half has put them within reach of some interesting history.
If they can build on their 17-7 (.708) start after the All Star break, and go 29-18 (.617) from here on out, they will have completed the best 1st half-to-2nd half improvement in the history of MLB, surpassing the 1997 Phillies team.
On the left-hand side below are the 10 biggest percentage improvements in W-L% from a team's first half of the season, to their second half.
The second set of columns show what the 2015 Phillies would have to do in the second half to beat each those levels of improvement. For example if they go 46-25 (.648) in the second half, that will be a 103.1% improvement over their first half W% of .319, and would make them the all-time "champs".
They "only" need to go 25-22 the rest of the way for the 3rd greatest half-to-half improvement ever. That would give them a second half W% of .592 (42-29), or 85.4% better than the first half's .319.
Thanks to that 17-7 start they only need to win 20 of their final 47 games (.426 W%) in order to make it onto this top 10 list. It's a good bet that they will be able to do that.
Obviously the preceding ignores the impact that all of this winning would have on their future fortunes, including 2016 draft position, allocated slot money, etc. Winning 29 of their final 47, for example, would put them at 75 wins for the season, which would likely be somewhere in the #8 to #12 range in 2016 draft order. In 2014, 2013, and 2012, it would have been the 10th, 12th, and 11th worst record, respectively. Current Fangraphs projections for final 2015 records would put 75 wins at 8th worst.