The other word we will stipulate is "ethics". 

Ethics is the study of values, and thus must invariably relate to opinion - in other words, that which is subjective.

When we are talking about ethics, we are talking about a specific view or opinion of what is good or bad.  This is bound to vary, and thus cannot be considered a principle.

Let us pause for a moment in our consideration of this tricky and muddled area of human behavior and conduct, and consider the physical sciences.

In place of the word "morality", let us simply use the word "principle".  In the place of the word "ethics", let us use the word "utility".

In the physical sciences, we have learned and come to understand a great many principles - which we refer to as scientifc principles or "laws".

In the physical world, these rules refer to the predictable and uniform outcome of certain types of actions.

For example, we know that if we take water and put it into a container, expose that container to sufficient quantities of and duration of heat, that in time the water will undergo a change in appearance and composition.  In short, it will boil.

Anyone can conduct this experiment.  There isn't anything magic about it.  The results are predictable, and will always be the same.  Always.  No exceptions.

The amount of time required to bring the water to a boil will vay depending upon the amount of water, the nature of the container, and the degree of heat applied. 

It will also boil after different times and at different temperatures, depending upon the elevation above sea level, the density of air pressure, and so on.  But there is no question about the fact that the water will boil if the conditions stipulated are followed.  The principle is a fact.