Every now and again, I'll be posting different articles about football philosophy pertaining to my personal beliefs about the sport and offering evidence to support my claim. All arguments have holes, and at the end of these I'll offer a poll as an outlet for your opinion. As always with BGN, your comments are more than welcome.

At the risk of sounding pretentious, I pulled out an old high school biology term for my first post. For the most part, this is a good debate for the offseason - dissecting last year's iteration of the Philadelphia Eagles and then using that information to see how things can be improved for the kickoff in September. However, instead of dissecting individual weaknesses on offense and defense, this article will cover how both units interact with each other and how the performance of one influences the performance of the other.

Symbiosis: according to the Merriam Webster Online Dictionary, it is defined as "a cooperative relationship (as between two persons or groups)." This could not be truer in the NFL, and it is an often-overlooked trend that has stood the test of time. Essentially, in every NFL team there is a balance between offense and defense. At the risk of sounding philosophical, as with everything in nature, a professional football team strives to find an equilibrium between its offensive and defensive units, with one often being the 'dominant' unit that influences the performance level of the other. This is seen constantly within the NFL - teams with great defenses have less than stellar offenses, and teams with a high-powered offense tend to give up points on defense.

As a current example, here are the teams with the top five scoring defenses in the league last year. Their rank in scoring points offensively is next to them in parenthesis.

Overall, there was a pretty significant space between their defensive scoring rank and their offensive scoring rank. The Texans bridged that gap the best by having the tenth-best scoring offense. While San Francisco and Baltimore were not far behind, their points forced per game was still in the low twenties - not 'high-powered' by any means. In contrast, here were the top five scoring offenses in 2011, with their defensive scoring ranks in parenthesis:

These differences were even larger. But in the end, it is pretty clear that the top offenses have mediocre defenses and the top defenses have above-average offenses at best (Houston is probably in the best shape, since they finished tenth in scoring with their third-string quarterback). In the NFL, teams with an outstanding offense and defense just do not have a complementary unit to match.

This brings us back to the idea of symbiosis and equilibrium. For some reason, the idea of a team having an unbelievable offense and defense just doesn't sit right, there's something off about it. Teams have gotten close, having strong offenses and defenses in the middle of the season, but one unit seems to peter out come December (see: 2008 New York Giants).

The most competitive teams are the ones that are able to manipulate the symbiosis in their favor. Every team with potential has a 'dominant' unit - one which consistently outperforms the other. This unit has the luxury of setting the team's identity, which strongly influences the play of the complementary unit. For example, the 2009 Saints' offense was their dominant unit, and set an identity of a team that can score early and often. Their defense (in addition to rolling out bonuses for injuring their opponents) responded by giving the ball back to their offense so they could score again. On the other side of the coin, strong defensive teams like the 49ers and Texans often rely on a good, clock-controlling run game since their defense is usually not on the field very long.

A potentially good team - like the 2011 Eagles - becomes bad when its complementary unit fails to meet the standard of equilibrium the dominant unit created, or when the dominant unit sends 'mixed messages' concerning the team identity. Last year, the Cleveland Browns had a great defense but were simply unable to score points to compete; the Carolina Panthers were able to score with the best of them but could not prevent their opponents from getting in the end zone. This lack of symbiosis often spells doom and high draft picks for teams.

So - finally - we come to the 2011 Philadelphia Eagles. How do all of these ideas of equilibrium and symbiosis fit in with them? Well, considering that they missed the playoffs last year, it's pretty obvious that they did not fit well. But here's the kicker (and the controversial claim): it wasn't their defense that failed them. It was their offense.

It is fair to say that the Eagles' offense is their dominant unit. It has the most electrifying players and was able to move the ball at will at certain times last season. By the reasoning given above, this would make the defense the complementary unit, which only acts to supplement the offense. A lot of people would say that the defense failed in this regard. I'm going to try and prove those people wrong.

For fun, let's take a look at the top five offensive teams last year, in terms of yards per game:

New Orleans Saints New England Patriots Green Bay Packers Philadelphia Eagles Detroit Lions

Now take a look at the top five offensive scoring teams that I listed above. Notice a correlation? With the exception of the Eagles, all of the other top-five offensive teams also scored the most points. The Eagles were bumped all the way down to eighth. The reason for this is no secret: turnovers. The inability to produce or prevent turnovers can wreak havoc on equilibrium, and it had its way with the Eagles last season.

So, based upon the connection between yards forced and points scored, it is safe to assume that the Eagles should have been scoring points on the same level as the other teams on those two lists. If you average out their points scored per game, you get an average of thirty-two points (rounding up). Had the Eagles scored thirty-two points every game last season, how many games do you think they would have won? Ten, maybe eleven?

Try fourteen.

That's right - the Eagles would have lost only two games last season if they scored the types of points they arguably should have been forcing. Those two games were Atlanta (35 points) and New England (38 points). That would have earned them a #2 Seed in the conference and a first-round bye. Crazy, right?

In all fairness, the defense did not leave much room for error. Had the Eagles fallen to the bottom end of the spectrum - the twenty-nine points per game Detroit was scoring - they would have lost four additional games: New York Giants (29), Buffalo Bills (31), Chicago Bears (30), and the Seattle Seahawks (31). I'll give that tie to the Giants since they knocked Michael Vick out of the game. Still, going 10-6 would have been enough to get them the division title.

What does all of this mean? It means that while the defense wasn't perfect, it should have been good enough with the way the Eagles were able to move the ball on offense. But the disgusting amount of turnovers they suffered last year single-handedly ruined their season. The offense ended up sending mixed signals to the defense, moving the ball like a team that scores a ton of points but then failing to produce results. The defense became a team that would be good for a team that can score and ended up becoming the scapegoat when the offense faltered.

This is not to say the defense was elite. It was far from it, and all of the moves the front office has done the defense should show marked improvement next season. But the idea that it was the defense that ruined the Eagles' season is just flat-out not true. It was the offense's propensity to commit turnovers that not only hindered their scoring but also put the defense between a rock and a hard place.

Finally, we come to the fork in the road, the 2012 season. Which path will the Eagles take? On paper, the Eagles additions in defensive personnel most definitely put them in a position to improve next season. Of course, 'on paper' does not always translate perfectly into reality (a subject for another post, perhaps?) so we'll have to wait like we do with everything else. The offensive side of the ball is a little more difficult to put a finger on. Turnovers aren't really quantifiable in the NFL; you can't get a new coach or new players and call the problem 'fixed' (Rex Grossman is a rare exception). A problem like that rests solely on the mentality of the players. It's up to people like Michael Vick, responsible for around twenty of the Eagles thirty-eight turnovers, to take a hard look in the mirror and notes on film to improve their play.

The good news is that the Law of Averages suggests the Eagles should commit fewer turnovers next season. But that alone may not be good enough; it will probably take individual effort on the part of the players to really solve the problem. With an improving defense that was already "good enough" last season, a commitment by the players to become great and improve upon their faults may be sufficient to field a team in September that could be fighting to hoist the Lombardi Trophy next February.