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legal education and writing

a priori

A priori refers to an assertion based on prior knowledge or intuition. In Latin, the term literally means “from what is earlier.” An a priori determination is formed before investigation. For example, assuming that the road will be wet when it stops raining a minute before would be a priori reasoning.   

A priori is the opposite of a posteriori, or after-the-fact knowledge.

ab initio

Ab initio is a Latin term that means "from the beginning” or “from inception.” Ab initio is used to indicate that some fact existed from the start of a relevant time period. It is often used as part of the phrase “void ab initio,” meaning something – such as a marriage – was void from the beginning.

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