Based on the widely accepted belief that experts know what they're talking about; also related to the idea that if enough important people say it, you should say it too.

• names of famous, respected people

Dr. Samuel J. Dorpenmacher, Charles Darwin

• credentials, titles, references to experience, etc.

While I was in Kenya assisting Dr. Livingston with his primate research.…

• citations

Radioactivity is actually great for you (Mdm. Curie, 1864; Oppenheimer et al., 1945).

The use of impressive, descriptive or evocative language to persuade

Examples:

• How can we hope to resist an irresistible force?
• Eschew obfuscatory irrelevancies.
• Ignoring these ecological needs will leave us with a barren wasteland rather than a blooming, productive, thriving garden.

Examples:

• A study of 14,000 female nurses between the ages of 30 and 45 recently demonstrated that being even 5-10 pounds above the recommended weight creates a substantial risk of death from heart disease for middle-aged women.

• Over 85% of MIT students are severely sleep-deprived, according to a recent survey. MIT professors are creating this unfortunate health risk by assigning too much homework.

Reasoning from a general principle to a specific application; emphasizes principles, values, beliefs, shared assumptions, well-accepted ideas

• Since we know that water pools at the lowest point, we can recognize that Martin Valley will be subject to floods and thus, that it is not an appropriate site for our nuclear power plant.

major premise: A > B If A, then B. A = B

minor premise: B > C A. C = B

conclusion: Therefore A > C Therefore, B. A = C

• Overuse of antibiotics assists the growth of resistant bacteria.

extended syllogism:

• Water pools at low points.

Floods are water.

Floods are likely at low points

Martin Valley is a low point.

Floods are likely at Martin Valley.

Flood-prone sites are not appropriate for nuclear plants.

Martin Valley is not appropriate for nuclear plants.

enthymeme: usually "[conclusion] because [premise]"

• Martin Valley is not an appropriate nuclear plant site because it's prone to flooding.

• Running is healthy because it increases cardiovascular function, metabolic activity, and muscle strength.

Points out similar characteristics; often used to help people understand unknown things via similarities to known ones

• Writing is like skiing: it's exhilarating, challenging, and fun.
• The new Martin Valley power plant will be roughly the size of a football field, allowing space for two reactors.
• Snake tongues are sensitive receptors, reacting to temperature with the same efficiency that radio antennas receive radio waves.
• How would you like to be put in a 4-cubic-ft cage so scientists could learn about human behavior?