This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong; it cannot perjure itself; it cannot be wholly absent. Only its interpretation can err.
Oath definition, a solemn appeal to a deity, or to some revered person or thing, to witness one's determination to speak the truth, to keep a promise, etc.: to testify upon oath. See more. Dictionary.com
An oath or affirmation is a type of attestation (swearing) that a Notary Public administers as. part of the jurat. This oath or affirmation binds the person to the actual oath or affirmation. The difference between the oath and affirmation is that the affirmation takes out the reference.