not a defense, but might be used to show lack of mens rea
- MPC: requires aquittal if negates mens rea/ does not work if person is guilty under his assumeb information. ( if crime is still a crime even with mistake)
- burden of proof: Prosecution must prove mens rea, therefore if D raises mistake which shows reasonable doubt, the aquittal.
GENERALLY: mistake of fact needs to be reasonble. by reasonable person test. with specific intent, many courts do not need to show reasonability for mistake for the specific intent crimes.
STRICT LIABILITY: the offense does not require a mens rea, but maybe it can be used as a defense ( not to negate mens rea, but as a defense)