Pencil lead is composed of pure carbon, and pencil lead is very cheap. Diamonds, like pencil lead, are composed of pure carbon. Therefore, probably diamonds are very cheap.
A) Deductive, invalid.
B) Inductive, strong.
C) Deductive, valid.
D) Inductive, sound.
E) Inductive, weak.

Question

Quizplus · Accepted Answer

The argument is inductive because it makes a probable conclusion based on specific observations. However, it is weak because it overlooks significant differences between pencil lead (graphite) and diamonds, such as their crystal structure and rarity, which greatly affect their value.

Pencil Lead Is Composed of Pure Carbon, and Pencil Lead