This is a simple matter of logical deduction. If the first principle of Natural Law is that the individual has free will, it naturally follows that the individual is responsible for their actions. One cannot do something outside the law and then claim not to be responsible for having done it (this claim presupposes an understanding of the principles of Natural Law vs. Civil Law). By performing an unlawful action, a person is admitting to their guilt. For example:
If I take something that I know belongs to another person, my actions demonstrate that I care more about my desire to have the thing I took than I care about the rights of the other person, or the principles of Natural Law. By taking the object, I admit my guilt through my actions. Thus, my action is a confession. It is that simple.
Nor can a person transfer responsibility to another person. This is because we are the only person who commands our will. Our bodies cannot act unless we will them to do so. Therefore, no one can force us to do something against our will. If we do something, we admit — by our action — that we want to do it. This means we cannot claim that another person is responsible for our action. Again, our action is a demonstration of our will. Returning to our example:
If I am caught unlawfully taking something from another person, I cannot avoid my guilt by claiming someone told me or forced me to do it. I could have chosen not to take the object. Even if I were being told to take it or I will be killed, I am still responsible for my actions. This is because I can choose to let myself be killed before I chose to trample on the rights of another person and violate the principles of Natural law.
Now, at first glance, most will probably think this claim to be too harsh — but it isn’t. Natural Law is impartial: it does not place the rights of one person over another. Natural Law dictates that we cannot do anything that unlawfully tramples the rights of another person — period! Unlawfully taking the property of another person tramples their right to free will by trampling on their labor and their right to sustain themselves so that they can exercise their free will (for a complete explanation of why this is true, see the rest of my posts under this heading). Even if I am starving, it does not justify me taking food from another person. By doing so, I would still trampling on the rights of another person.
To drive this point home, let us take this to the extreme example of a life and death situation. Suppose we are faced with a situation where we must kill another person or we, ourselves, will be killed. In this case, Natural Law dictates that we must allow ourselves to be killed. If we chose to save ourselves by killing the other person, we are guilty of murder. Even if a third party is the one forcing us to make the choice by holding a gun to our head, if we kill to save ourselves, we commit murder. We cannot blame the person holding the gun to our head because they gave us a lawful choice: to let them kill us. Therefore, if we save ourselves, our action demonstrates our guilt. We put ourselves before another, and this violates Natural Law.
Incidentally, this same principle applies to things. One cannot claim, “The government made me do it.” Nor can one claim, “The devil made me do it.” So long as a person is of sound mind (note: I did not say sound body), that person is responsible for every action they perform, and confesses to any and all violations of Natural Law that may be associated with that action. Blame can never be transferred to another person or thing because the individual’s will is theirs and theirs alone.