It is cruel to leave a dog not knowing what he or she should or shouldn't do. Your dog needs to know the rules of the house in order to become part of your family circle and to bond with you. Every breed was developed to do a specific job for people. In our current world the main job for most dogs is to be a good companion. While they may have other jobs such as watching your house or going jogging with you, they are friends first and workers second.
All dogs have to be taught to do their jobs.
Companion or service dogs have to be taught how to do their jobs too. Most dogs were bred to like people but they have to learn to be a good family member and a well-behaved member of the community. No dog knows how to behave without training any more than people do. Start training early. Start training as soon as you get your dog.