Quick Answer: A fact is a true datum about one or more aspects of a circumstance. Standard reference works are often used to check facts. Scientific facts are verified by repeatable careful observation or measurement by experiments or other means. Generally speaking, facts are independent of belief, knowledge and opinion. Facts are different from inferences, theories, values, and objects. For example, "This sentence contains words." accurately describes a linguistic fact, and "the Sun is a star" describes an astronomical fact. Further, "Abraham Lincoln was the 16th president of the United States" and "Abraham Lincoln was assassinated" are both historical facts.