Many of the Declaration's principles are broad and idealistic. This is because such principles are not meant to be taken literally. Instead, they are meant to inspire a feeling and a general attitude towards life, that will be modified and developed based on the laws that are afterwards established.
An example of such a principle is the idea that all people have a right to the pursuit of happiness. This, taken literally, would mean that every person has the right to do whatever makes them happy. If it was established as a law, it would prevent the implementation of other laws that curb such liberties. It would allow people to act in any way they want, regardless of whether their way is illegal or immoral.
