A principle is a law or rule that has to be, or usually is to be followed, or can be desirably followed, or is an inevitable consequence of something, such as the laws observed in nature or the way that a system is constructed. The principles of such a system are understood by its users as the essential characteristics of the system, or reflecting system's designed purpose, and the effective operation or use of which would be impossible if any one of the principles was to be ignored.
Examples of principles are descriptive comprehensive and fundamental law, doctrine, or assumption, the normative rule or code of conduct, and the law or fact of nature underlying the working of an artificial device.
Depending on the way the cause is understood, the basic law governing that cause may acquire some distinction in its expression.
Of causality, as efficient cause
The efficient cause is the one that produces the necessary effect, as long as the necessary and sufficient conditions are provided.The scientific process generally consists of establishing a cause by analyzing its effect upon objects. In this way, a description can be established to explain what principle brought about the change-effect. For this reason the principle of cause is considered to be a determining factor in the production of facts.
The principle of causality states that "every event has a cause"; for instance, everything that begins to exist must have a cause. It was formulated by Aristotle's theory which states that: "Everything that moves is moved by another". This principle, in conjunction with the principle that an infinite regress is not possible, has been used to argue for God's existence. The principle of causality is often associated with the similar, though distinct, principle of sufficient reason, according to which, there is a reason why everything is the particular way it is rather than some other way.
As a final cause
Final cause is the end, or goal, which guides one to take the necessary actions to obtain it.
For that there needs to be an intelligence capable of conceiving the end and realizing that certain actions must be taken to achieve the goal.
Science does not recognize the finality of the natural causes as a guiding principle of investigation.
It is also understood therefore that the principle guides the action as a norm or rule of behaviour, which produces two types of principle.
As moral law
A principle represents values that orient and rule the conduct of persons in a particular society. Principles are absorbed in childhood through a process of socialization. There is a presumption of liberty of individuals that is restrained. Exemplary principles include First, do no harm, the golden rule and the doctrine of the mean.
As a juridic law
It represents a set of values that inspire the written norms that organize the life of a society submitting to the powers of an authority, generally the State. The law establishes a legal obligation, in a coercive way; it therefore acts as principle conditioning of the action that limits the liberty of the individuals. See, for examples, the territorial principle, homestead principle, and precautionary principle.
As scientific law
Archimedes principle, relating buoyancy to the weight of displaced water, is an early example of a law in science. Another early one developed by Malthus is the population principle, now called the Malthusian principle. Freud also wrote on principles, especially the reality principle necessary to keep the id and pleasure principle in check. Biologists use the principle of priority and principle of Binominal nomenclature for precision in naming species. There are many principles observed in physics, notably in cosmology which observes the mediocrity principle, the anthropic principle, the principle of relativity and the cosmological principle. Other well-known principles include the uncertainty principle in quantum mechanics and the pigeonhole principle and superposition principle in mathematics.
As axiom or logical fundament
Principle of sufficient reason
The principle states that every event has a rational explanation. The principle has a variety of expressions, all of which are perhaps best summarized by the following:
- For every entity x, if x exists, then there is a sufficient explanation for why x exists.
- For every event e, if e occurs, then there is a sufficient explanation for why e occurs.
- For every proposition p, if p is true, then there is a sufficient explanation for why p is true.
However, one realizes that in every sentence there is a direct relation between the predicate and the subject. To say that "the Earth is round", corresponds to a direct relation between the subject and the predicate. Taking this to the sentence "the being is the being", we realize the principle of identity that the being possesses.
Principle of non-contradiction
"One thing can't not be and be at the same time, under the same aspect." Example: It is not possible that in exactly the same moment and place, it rains and doesn't rain.
This principle does not work for non physical events Example: The move it or lose it rule...if you are not moving you are losing what ever it is at the very same time. Procrastination is putting something off yet at the same time, it is doing harm to character building.
Principle of excluded middle
The principle of the excluding third or "principium tertium exclusum" is a principle of the traditional logic formulated canonically by Leibniz as: either A is B or A isn't B. It is read the following way: either P is true, or its denial ¬P is. It is also known as "tertium non datur" ('A third (thing) is not). Classically it is considered to be one of the most important fundamental principles or laws of thought (along with the principles of identity, no contradiction and sufficient reason).
- The dictionary definition of principle at Wiktionary