I have a thing for old, dead guys. Sure, they're a little dusty, but you just wipe off their tomb--er, tome--and you'll see they can breathe fresh life into your writing.
There's this particular old dude Aristotle whose advice I've taken to heart for myself. He used to be a tutor himself to Alexander the Great in ancient Egypt. He taught biology, physics, geography, oration, and--most importantly for us!--rhetoric.
There's a fancy definition for rhetoric, but the basic idea is this: There're a series of ways to sway an audience to your own opinion and view, be they in person or on paper. The art--and yes, it's an art--of doing this well is called rhetoric.
According to Aristotle, there were three ways to go about convincing people that your way is the right way. He called them "logos," "pathos," and "ethos." You can use one, two, or even all three in combination. In order to use them, however, you have to know what they are. (It's all very well and good to know you need a screwdriver to put a screw in something, but if you don't know what one looks like, you won't find it in your toolbox!)
For now, let's start with pathos.
Pathos is an appeal to the audience's emotions. People use this appeal all the time--ever see a commercial asking for donations to the animal shelter with all those big-eyed, cute puppies? Pathos. Did you ever listen to a prosecutor arguing in the courtroom, defending a murderer because he was abused when he was younger, had no money, and didn't get a date to prom? Pathos. Have you ever read a magazine ad, advertising a scent (presumably) worn by the female posing in glossy four-color? Yep, you guessed it--pathos.
Anything that tugs at your heartstrings is pathos at work. The way I remember pathos is this very simple saying: "Pathos equals pandas!" Everybody loves pandas; everybody wants to save them. Ever ask yourself why? I mean, it's not like they build cathedrals or pull war chariots or fetch sticks. They sit around and eat bamboo in a country halfway around the world from where I live. There's no rational reason why I should care.
But pandas are cute. Their big heads and fluffy bodies trigger an immediate emotional reaction. They are adorable, and I want to protect them. Add on their fight against 'evil' progressive capitalism destroying their home for greed, and you've got a martyr. Martyrs are nothing if not emotional rallying points.
Pathos isn't always a warm, fuzzy feeling like with the pandas. Lust, fear, pride, and disgust can all be used to convince someone to do something (or to talk them out of it).
Let's go back to the perfume example above. You can't smell the perfume, so you have no idea if its scent is one you prefer, but the picture of the beautiful woman--possibly scantily clad or provocatively dressed--is arousing. You want to be like that woman, or attract women like that. Either way, the ad uses sensuality to convince you to purchase the perfume.
A common rhetorical strategy in politics is manipulation of the populace using fear. ("They'll take away your right to own guns! You'll never be safe again!" or maybe "They're trying to tell you what to do with your body! You'll lose your freedom!")
I once passed a 10-foot-high glossy banner of an aborted fetus at a pro-life rally on my campus. I was repulsed and didn't want to have anything to do with it, which was exactly the response the protesters were looking for.
If those examples of the power of rhetoric don't convince you, think of this: a homicidal psychopath played on the pride of a poor, discouraged nation to attempt one of the greatest genocides in human history. The Holocaust destroyed homes, lives, and cultures--all because one man managed to stir up a nation by using pathos.
Pathos is a powerful tool when used well. There can be downsides, as well--you may risk coming across like a giant butterball who hasn't thought everything through--but that's why you have logos and ethos to help prop up your argument. We'll talk about logos next time, but I hope that my quick explanation helps your writing improve!