Gregor Reisch, Logic presents its main themes. Margarita Philosophica, 1503 or 1508. In the engraving, two dogs named veritas (truth) and falsitas (falsehood) chase a rabbit named problema (problem). Logic runs behind the dogs, armed with the sword syllogismus (syllogism). In the bottom left corner, the philosopher Parmenides can be seen in a cave.

Logic is the study of reasoning. The rules of logic let philosophers make a guess about logical deductions about the world. Logic helps people decide whether something can be true or false.

Logic is often written in syllogisms, which are one type of logical proof. A syllogism is made from a collection of statements used to logically prove the final statement, called the conclusion. One popular example of a logical syllogism was written by the Classical Greek philosopher Aristotle:

1. All men are mortal.
2. Socrates is a man.
3. Therefore, Socrates is mortal.