Final answer:
Strict liability crimes do not need proof of mens rea, focusing instead on the actus reus. Defendants can be found liable even without intention to cause harm. Societal welfare and safety concerns underpin the rationale for these types of laws.
Step-by-step explanation:
Strict liability crimes are a special category of offences that do not require proof of mens rea, which is the intent or knowledge of wrongdoing. Instead, strict liability only requires demonstrating that the defendant performed the prohibited act (actus reus). In doing so, it shifts focus from the defendant's state of mind to the mere occurrence of the event. This means that even if the defendant had no intention to cause harm, they can still be found liable for committing the act itself.
For example, traffic offenses and violations of health and safety codes are often considered strict liability crimes. The rationale behind such laws is to promote societal welfare by encouraging higher standards of care. However, defenses like mistake or ignorance of the fact may not be acceptable in strict liability cases unless the statute expressly provides such defenses.