Last week when Ally Hodgson asked how learning about claims would make her life better I answered somewhat clumsily with a brief argument about vaccination. Do you remember the argument? Good. Did you notice that it contained elements of logos, ethos, and pathos? Very good.

The whole argument can be rendered in a single sentence: If you can’t recognize that the claim that vaccination causes autism is weak and unpersuasive, you might decide on the basis of illogical fear to withhold vaccines from your own fragile child, not only endangering the helpless infant in your care, but also risking the lives of every innocent child she contacts.

• LOGOS
  The logical argument here, based on several unspoken premises (warrants for Toulmin) that might be argued but are generally accepted, is that Ally’s actions will be guided by what she believes to be true, that her ability to analyze arguments will guide her to the truth, and that she will be well served by basing her choices on truth rather than on false claims and groundless panic. Very few words account for all these claims: among them, recognize, unpersuasive, decide, and illogical.
  Whether polio can be eradicated is a logical question.
• ETHOS
  The ethical argument, also contained in just a few words, also based on unspoken premises, is that Ally has social obligations to keep her child safe and not endanger the public. These claims, while generally accepted, are the subject of lively debates about the degree to which we are obligated to others, and the relative strengths of our conflicting obligations.
  Whether children should be inoculated against polio by force or deception are ethical questions.
• PATHOS
  Raising the specter of pathetic, ill children paralyzed or dying of preventable childhood illnesses was my way of dramatizing the logical and ethical terms of the argument to bully Ally emotionally. Contained in just a few words—fragile, innocent, helpless—arguments of pathos can be very effective, even when they are not based on strong claims.
  The argument that “to condemn even one child to a lifetime of paralysis” is sufficient reason to adopt (or to withhold) a massive global health program, makes sense only to our emotions.

As I have elsewhere, I want to emphasize here that claims hide everywhere, often in single words, or even between the lines. Artful arguers get us to nod in agreement without having to say much. If they combine logos and ethos, they can make us conclude that we have obligations to act based on very few facts. And if they mix in a little pathos, they can make us feel ashamed to even think of asking for additional evidence.