3.1 - Formal vs. Informal Fallacies

determine whether the following are formal or informal fallacies. If you can, specify the type.

All bullfights are grotesque rituals. 

All executions are grotesque rituals. 

Therefore, all bullfights are executions. 

Formal fallacy; categorical syllogism

If apes are intelligent, then apes can solve puzzles.

Apes can solve puzzles.

Therefore, apes are intelligent.

Formal fallacy; hypothetical syllogism

The brooklyn bridge is made of atoms. Atoms are invisible. Therefore, the brooklyn bridge is invisible.

Informal fallacy; composition (parts —> whole)

A chess player is a person. Therefore, a bad chess player is a bad person.

informal fallacy; composition? (not sure)

If Rasputin was really mad, then he deceived Czar Nicholas II. Rasputin was not really mad. Therefore, he did not deceive Czar Nicholas II.

Formal; hypothetical syllogism

Everything that runs has feet. The Columbia River runs very swiftly. Therefore, the Columbia River has feet.

informal; equivocation “runs”

All people who believe we create our own reality are people who lack social responsibility. All people governed by selfish motives are people who lack social responsibility. Therefore, all people who believe we create our own reality are people governed by selfish motives.

formal; categorical syllogism

The ship of state is like a ship at sea. No sailor is ever allowed to protest orders from the captain. For the same reason, no citizen should ever be allowed to protest presidential policies.

informal; weak analogy

Renowned violinist Pinchas Zuckerman has said, “When it comes to vodka, Smirnoff plays second fiddle to none.” We must therefore conclude that Smirnoff is the best vodka available.

informal; appeal to unqualified authority

If the Chinese government systematically kills its unwanted orphans, then the Chinese government is immoral. The Chinese government is indeed immoral. Therefore, the Chinese government systematically kills its unwanted orphans.

formal; hypothetical syllogism

Mark Ruffalo, America Ferrera, and Ben Affleck are Democrats. Therefore, it must be the case that all Hollywood stars are Democrats.

informal; hasty generalization

Mark Zuckerberg, cofounder of Facebook, argues in favor of opening up the Arctic National Wildlife Refuge to oil drilling. But consider this: Zuckerberg is just a moneygrubbing capitalist who only cares about inflating his already bloated bank account. Clearly his arguments are ridiculous.

informal; ad hominem abusive

If plastic guns are sold to the public, then terrorists will carry them aboard airliners undetected. If plastic guns are sold to the public, then airline hijackings will increase. Therefore, if terrorists carry plastic guns aboard airliners undetected, then airline hijackings will increase.

formal; hypothetical syllogism

Some corporate mergers are arrangements that produce layoffs. Some arrangements that produce layoffs are social catastrophes. Therefore, some corporate mergers are social catastrophes.

formal; categorical syllogism