Factual and Theoretical Differences

Historical sources always agree and indicate the same information

• Yes

• No

When sources disagree they must both be incorrect

• No
• Yes

The two main types of differences in sources are

• Factual differences
• Theoretical differences
• Philosophical differences
• Opinion-based differences

The Crusades started in 1095

and

The Crusades started in 1096

are:

• Contrary

• Contradictory

a proposition so related to another that though both may be false they cannot both be true

• Contrary

• Contradictory

A proposition so related to a second that it is impossible for both to be true or both to be false.

• Contradictory
• Contrary

Two statements in which one must be true​ but both cannot be true

• Contradictory

• Contrary

Both can not be true at the same time

• Contrary
• Contradictory

A piece of information presented as having objective reality

• Fact
• Theory

an unproved assumption

• Theory
• Fact