A principle is an abstract object which signifies a point (or points) of probability on a subject (e.g., the principle of creativity), which allows for the formation of rule or norm or law by (human) interpretation of the phenomena (events) that can be created. The rules, norms and laws depend on and co-create a particular context to formulate.
A principle is the underlying part (or spirit) of the basis for an evolutionary normative or formative development, which is the object of subjective experience and/or interpretation. For example, the ethics of someone may be seen as a set of principles that the individual obeys in the form of rules, as guidance or law. These principles thus form the basis for such ethics.
Reducing a rule to its principle says that, for the purpose at hand, the principle will not / cannot be questioned or further derived (unless you create new rules). This is a convenient way of reducing the complexity of an argumentation.
The point of principle allows to create all probable versions under its subjective theme, as its reality creation/evolvement under that subject is open-ended and unpredictable relying on choice and option. Rules and laws capture a consensus that certain actions and events will occur under a principle (or a combination of principles).
A principled view for example, implies that an individual has a firm understanding of the underlying principle(s) of events and the rules and laws which govern them inherently and according to our consensus.