I disagree with your last paragraph. You have to have a "meeting of minds" and signatures of both parties to establish a valid contract.
Artificial "persons" have no mind and can't hold a pen. This implies that contracts can ONLY be established by natural persons. Artificial persons have to have an "agent" perform the work (that only natural persons can do) for them.
"I do not add 'within the limits of the law,' because law is often but the tyrant's will, and always so when it violates the right of an individual."