Principles describe or explain aspects of reality that are universal and absolute. Universal means they are true in all cases where the principles apply. Absolute means they are invariable and not contingent on anything else.
Most principles are stated as propositions, but can be put into other forms, such as the periodic table of chemistry, which is an excellent example of principles. The properties assigned to each of the chemical elements in the periodic table will be true of those elements in all cases, and no state or relationship can change those properties. There is a simple ontological reason why this is true. A thing's properties (qualities, characteristics) do not simply describe what a thing is, they are what a thing is.
All of chemistry and all that is possible to that field as a technology is only possible within the limits of those principles identified in the periodic table. While they are not the only principles in chemistry, nothing will succeed that attempts to evade or defy these principles.
No chemical engineer would dream of attempting to evade any principle of chemistry because he knows such an evasion would surely fail. Yet, in life most people evade and defy principles all the time even when they know what those principles are, which is why so many people's lives are such disasters.
Principles of Ethics
Just as the principles of chemistry do not tell a chemist what to do, but define the possibilities and limits of what can be done and determine the consequences or results of any particular experiments or processes, moral or ethical principles do not tell one what to do, but define the possibilities and limits of what is possible and determine the consequences of any chosen actions.
Ethical principles do not tell one how to live, they only tell one, "if you live this way, these will be the consequences."
In general, it is assumed the objective of ethical principles is human success, that ethical principles will be used for ones survival and achievement of happiness as a human being in the real world in which they live.
This assumption is not universal. For many people the objective is not life in this world, but some fictitious future world or future life. In those cases the principles of ethics will not be used to achieve success in this life, but something else, with predictable consequences.
The remainder of these comments pertain to ethics as the means to human life and happiness in this world. Ethical principles used to that end are called moral values.
Ethics Pertains Only To Individual Human Beings
All principles are needed because human beings are volitional creatures, which means all their behavior in thought or action must be consciously chosen. Since principles define the relationship between actions and consequences, in everything a human being chooses to do, the principles that will determine the consequences of his action must be understood, because otherwise there is no way to prefer one choice over any other.
Moral or ethical principles pertain only to individual human beings, because only individual human beings are required to make conscious choice or have the capacity for such choice. Ethics does not pertain to societies or governments. Societies cannot make choices, only individuals within a society make choices. Governments cannot make choices, only the individuals that are the government make choices.
Some Ethical Principles
In all the following, "unethical," means contrary to the requirements of reality for the achievement of human life and happiness. "Must," means it is a physical or psychological necessity, not some kind of "moral imperative." The principle of ethics are not dictated, they are discovered and determined by the nature of reality itself: the nature of the physical world we live in, and the requirements of human nature, both biological and psychological.
Every individual not only can, but must consciously choose everything he thinks and does. [In this case "must" means one has no choice in the matter.] Any attempt to evade the fact everything one does is by choice, such as blaming feelings, desires, impulses, genetics, society, one's boss or "superiors," policy, duty, ill health, moods, or anything else, is unethical.
Every individual has their own mind and is responsible for everything they think, choose, and do. Any attempt to evade that responsibility is unethical.
Every individual has the ability to learn all they need to learn to be all they can possibly be as a human being, and they must learn all they possibly can about as many things as they possibly can and they must do this as long as they live. Not learning all one possibly can is unethical.
Every individual has the ability to think and reason well enough to make right choices about everything they do. Every individual must use their ability to reason about everything they believe, think, choose, and do; which means, they must never accept a contradiction, never surrender their reason to feelings, whims, desires, passions, or fears, and never just accept anything as true they do not themselves understand how and why it is true. Failing or evading to think as well as one possibly can about all things is unethical.
Every individual must use all their ability and effort to be and accomplish all they possibly can as a human being. Anything less is not only immoral but a failure to live the life that is possible, which will, at best, lead only to a life of regret and disappointment, but, more likely, to a life that ends in grief or despair. To do less than one's best in all things is unethical.
Reality does not supply human beings with the requirements of their life—neither food, clothing, shelter, medicine, or knowledge; these must all be produced by human beings. No one is born with a claim to any of these things and no one may morally seek what one has not produced, earned, or merited by ones own effort: not wealth, not goods, not services, not pleasure, not position, and not reputation. So long as ones wealth is produced by ones own effort, it may be traded for anything anyone else has produced. Acquiring or seeking anything by any means other than producing it, earning it, or buying it, is unethical.
Freedom is a moral requirement for all individuals. Every individual must seek to be as free as possible, free to use their minds to think whatever they choose, free to make any choices they judge to be right, and free to work and produce in any way they choose. Failing to seek to be free, or seeking freedom by any means other than earning it by one's own effort is unethical.
The only moral relationship between individuals is reason. Individuals may morally deal with one another by means of reason to their mutual benefit, socially, financially, in business or any other cooperative efforts, or any other way they mutually choose. All other relationships are unethical.
Every individual is different from every other individual. No individual can know what is right or good for any other individual. Any attempt to interfere in the life of any other individual to influence his thoughts or choices, by any means except reason, is unethical.
The last may be restated as a true golden rule:
"Do nothing unto others, ever!"
"Mind your own business!"
It is immoral to allow another individual to interfere in one's own life by any means. Rational discourse is not interference—everything else is. It is morally necessary to protect oneself, and ones property from such interference, by the most rational and economic method possible, including force to any degree when no other method is possible.
These are moral or ethical principles. They are not commandments, not instructions, and not rules. No one is required to observe any of these principles, but no one can evade them without consequence or penalty—not a penalty imposed by some agency or by anyone else, but a penalty imposed by reality itself.
Are these principles hard? Yes they're hard and yes they are demanding, as hard and demanding as life itself. To evade them is to evade life. No moral individual regards them as limits or restrictions on their life, however, because they are the means of achieving and being all that life makes possible. Living by these principles is the only way to live a life that is worth living.
Like all true principles, they are not limits or restrictions, but the keys that open the doors to possibilities that do not exist without them. Like the principles of mathematics that make it possible to answer questions about quantities and measurements which are impossible to answer without them, moral principles make it possible to know how to live successfully and without failure. Just as mathematical principles determine how mathematical problems must be solved successfully, and if the rules are violated, the mathematics will fail, so moral principles determine how one must choose and act to live successfully, and if the principles are violated, one's life will fail. Mathematical principles are not restrictions on the mathematician, they are the means to his success; moral principles are not restrictions on an individual's life, they are the means to his prosperity and happiness.