You have just murdered both your parents and your lawyer is making the case that since you are now an orphan you deserve the court’s sympathy.
And furthermore you are mentally-insane. So he calls in an expert-witness, a brilliant professor from a local university, a national luminary, in fact.
‘Sanity’ the professor judiciously declares ‘ is ‘Reflective Consciousness’. An ability to be conscious that you are conscious. And that is what tells a person what is right and what is wrong.’ [You remember the M’naghten Rule, don’t you?]
And since you are shortchanged on this essential endowment you cannot be held responsible. You need compassionate care for the emotional damage caused by witnessing your parents violent death.
You think I’m joking? This happens to be a true story with names changed to protect the innocence of the guilty.