How do you know the color blue that you see is the same color blue as seen by everyone else?

It's an old, philosophical (some would say, annoying) question that kicks off the latest Mad Men episode, aptly titled "The Color Blue." What relevance does it play during the episode?

Almost every character is forced to see an individual in a different light than previously imagined.

There's Pryce and his realization that his British bosses aren't remotely interested in Sterling Cooper as anything but a profit maker; there's Paul and his solemn discovery that, yes, Peggy is better at her job than he is.

And, of course, there's Betty. Poor, no-longer-innocent, overgrown child Betty. She always knew Don had secrets, but she never would have guessed the major one would be a previous marriage. To read how she comes across this information, follow our link to this week's episode guide.

Viewers know that Betty hasn't uncovered the exact secret Don has been keeping from the world, but that doesn't change the tension that now exists between her and her husband. We can't wait to see how this plays out.

Lastly, there's Don, forced to see himself in a worse light, as he watches how much Suzanne cares about her brother. Contrast this with the fact that Don drove his own sibling to suicide.

Can Don compartmentalize this reminder of his early let downs, as he does for everything else? He's sure gonna try. But will changing circumstances allow him to?

Below, we've collected a few of the top Mad Men quotes from the episode:

Kinsey: I had a great idea and I lost it.
Don: I hate when that happens. | permalink

Cooper: I didn't get to where I am by dwelling on the past. | permalink

Don: People may see things differently, but they don't really want to. | permalink

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.