Philadelphia Phillies First-Place Eliminiation Scenario
Philadelphia must win 11 more games (66 total) to avoid elimination from first place.
Here is a scenario in which Philadelphia can finish in first place with 66 wins.

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
New York         56	51	55	0.523	0.0
Philadelphia     55	53	54	0.509	1.5
Atlanta          54	54	54	0.500	2.5
Washington       49	59	54	0.454	7.5
Miami            46	62	54	0.426	10.5

Next, we show how the remaining series of games plays out in the scenario:

Atlanta wins 5 games against Miami and loses 1.
Atlanta wins 3 games against New York and loses 0.
Atlanta wins 2 games against Philadelphia and loses 1.
Atlanta wins 0 games against Washington and loses 9.
Atlanta wins 0 games agains teams outside the division and loses 0.

Miami wins 1 games against Atlanta and loses 5.
Miami wins 11 games against New York and loses 0.
Miami wins 6 games against Philadelphia and loses 0.
Miami wins 2 games against Washington and loses 7.
Miami wins 0 games agains teams outside the division and loses 0.

New York wins 0 games against Atlanta and loses 3.
New York wins 0 games against Miami and loses 11.
New York wins 0 games against Philadelphia and loses 6.
New York wins 10 games against Washington and loses 1.
New York wins 0 games agains teams outside the division and loses 0.

Philadelphia wins 1 games against Atlanta and loses 2.
Philadelphia wins 0 games against Miami and loses 6.
Philadelphia wins 6 games against New York and loses 0.
Philadelphia wins 4 games against Washington and loses 0.
Philadelphia wins 0 games agains teams outside the division and loses 0.

Washington wins 9 games against Atlanta and loses 0.
Washington wins 7 games against Miami and loses 2.
Washington wins 1 games against New York and loses 10.
Washington wins 0 games against Philadelphia and loses 4.
Washington wins 0 games agains teams outside the division and loses 0.

Combining the current standings with the wins and losses from the scenario results in the following final standings:
Team             W	L	PCT	GB
Philadelphia     66	96	0.407	0.0
Miami            66	96	0.407	0.0
New York         66	96	0.407	0.0
Washington       66	96	0.407	0.0
Atlanta          64	98	0.395	2.0


Next, we explain why Philadelphia cannot win the division with fewer than 66 wins.

There are a total of 68 games left in the following series of games between teams in the National League East:
Atlanta          vs. Miami            6 games
Atlanta          vs. New York         3 games
Atlanta          vs. Philadelphia     3 games
Atlanta          vs. Washington       9 games
Miami            vs. New York         11 games
Miami            vs. Philadelphia     6 games
Miami            vs. Washington       9 games
New York         vs. Philadelphia     6 games
New York         vs. Washington       11 games
Philadelphia     vs. Washington       4 games

For each team listed above, the table below shows the current number of wins in the (W) column.
The next column shows the maximum number of its remaining games that each team can win assuming that
Philadelphia finishes in first place with a total of 65 wins.

Team             W	Max Additional Wins
Atlanta          54	65 - 54 = 11
Miami            46	65 - 46 = 19
New York         56	65 - 56 = 9
Philadelphia     55	65 - 55 = 10
Washington       49	65 - 49 = 16
Total            260	65

Since the total of the Max Additional Wins column is less than 68, it is not possible for Philadelphia to win the division with 65 (or fewer) total wins.