An Introduction to Pathos

Aristotle divided rhetorical proofs into three kinds--logos (the appeal based in reason); ethos (the appeal based in the speaker's or writer's character); and pathos (the appeal based in emotion).  When a writer or speaker uses pathos to persuade the audience, he or she attempts to move them by putting them in the right frame of mind, or, put differently, to create the right disposition.  Pathos is the appeal most likely to get the audience to actually do something.  Logos may convince them of an idea's usefulness or truthfulness, and ethos may convince them that the idea is being presented for their own good, but it is pathos that activates the urge to respond.
Pathos, then, is emotion.  We can map motions along a continuum from mild to intense.  Mild emotions may not even seem to be emotions.  For instance, a relaxed disposition is important if the speaker wishes to take some time in developing ideas.  If the audience is on edge, they are not likely to listen carefully, so a good speaker attempts to create a relaxed disposition.  Similarly, if an audience is in a critical or resisting mood, it is very hard to get a fair hearing.  These states of mind may not seem to be "emotions," but they fall into the field of pathos.  Some moods, in other words, tend to be emotions at the mild end of the continuum.
At the intense end of emotions are those which "flame" up or that overwhelm.  Intense anger, for instance, will cause a person's face to turn red.  Remember times when you were so angry that you could hardly control yourself.  Similarly, intense sorrow or empathy may overwhelm a person causing him to break into tears.  Joy, or nostalgia, can also have similar effects on an audience.
Another way of thinking about pathos is to think of emotions as being variations of either desire or repugnance.  Basically, all emotions either draw you toward the subject being discussed or make you want to distance yourself from it.  You might think of this in terms of the subject's intonation as created by the speaker or writer.  If the writer wants to create a positive tone, she will create an image that "invites" the reader to come near.  Contrariwise, if she wishes to create a negative tone, she will create an image that repulses the reader.  
It is important that the emotion evoked serve the rhetor's purpose.  An example of a failed appeal to pathos was the attempt by some one from a pro-life group to get candidate Clinton's attention during his first run for the presidency.  Once, in a large crowd, he reached out to shake hands, and someone put a dead fetus in his hands.  The attempt was to shock him into the realization that a fetus is a human being, but the result was to create a repugnance, not toward the person who had performed the abortion, but toward the person who had put the fetus in his hands.
Appropriateness is all when it comes to using pathos, but how does one create an appeal to pathos or how does one recongnize such an appeal?  Normally, one's emotions are evoked by images.  When the mind pictures something (imagination), that image tends to have a tonal quality to it.  If the image shows an injustice, then the emotions of indignation will arise, causing the one who feels it to want to do something.  It is important, then, to use narrative and description carefully to create pathos.  The reader's emotions will be touched when he can "identify" with the image in some way, when he can put himself into it and see it as part of his life.  If you describe a little girl waiting for the return of her mother after a long wait, then a person who is a mother may think of her own children and feel a yearning to be with them.
Another thing that contributes to emotion is style.  It is difficult to be specific about this connection, but a dense style, as in a scientific article creates one kind of tone, whereas the free language of a short story creates another.  In some ways, this side of pathos is related to music.  Consider the mood created by music in a minor key:  one finds himself feeling a bit sad, without knowing why.  Or, perhaps, one hears a jubilant piece by Bach and finds his spirit singing with joy.  Just how the moods created by music can be translated into moods created by the style of language is not clearly understood, but it is worth while reading your writing aloud to listen to it.  Does it create the mood you want or not?
Recognizing the use of pathos in someone else's speech or text is a matter of reading the text in a non-critical attitude until you find your emotions being triggered.  When that happens, you can then look carefully at the text.  Is there a story being told?  A Description?  Is the language having an effect?  Has the writer created an image of herself that has caused repugnance?  Emotions reside in the one receiving the message; sometimes the speaker or writer tries to create emotions but fails; sometimes, such attempts even backfire.  As you read a text, look carefully both at places where your emotions are triggered and at places where you think the writer was trying to create emotion but failed to elicit any in your own reading.