A scientific law is a scientific proposition that affirms a constant relationship between two or more variables or factors, each of which represents a property or measurement of specific systems. It is also defined as a constant and invariable rule and norm of things, arising from its first cause or its qualities and conditions. It is usually expressed mathematically or in formalized language.
(Scientific theories explain why something happens, whereas Scientific Laws record what happens. )
General laws can be demonstrated by indirect evidence by checking verifiable particular propositions derived from them. Inaccessible phenomena are subjected to indirect tests by qualitative and quantitative assessment of the evolution of the effect they generate on other observable and experimental facts.
- In natural sciences a scientific law is a rule in which events of joint occurrence are related, generally causal, and which has been manifested following the scientific method. It is accepted that after a natural scientific law there is a certain necessary mechanism that allows events to happen in a certain way.
- In social sciences a confirmed scientific hypothesis refers to a characteristic common to many different social phenomena, of a regular or constant pattern over time in certain circumstances. It is said that social subjects behave under the same characteristics, that is, according to the law of behavior. Sometimes it is considered that some social laws are contingent or historically conditioned.
Popper, in a falsificationist conception of scientific rationality, affirmed that every natural law can be expressed with the affirmation that such and such a thing cannot happen.
Scientific law and science
The facts that evolve according to regular and constant patterns in science are described by means of a linguistic proposal or scientific law, which is an exposition of the facts in all their complexity. With experimental science begins the investigation of scientific laws linked to different phenomena. Galileo Galilei (1564-1642) wrote:
“If it is true that an effect is the consequence of a single primary cause and that there is a firm and constant link between the cause and the effect, it must necessarily be concluded that where there is a firm and constant alteration in the effect, there will be a firm alteration and constant in the cause.”
The physicist-mathematician Henri Poincaré (1858-1912) provides a similar definition:
“What is a law? It is a constant link between an antecedent and a consequent, between the current state of the world and its immediately subsequent state.”
The scientific activity is developed according to scientific laws. Hence the physicist Max Planck has proposed the following principles of experimental science:
- Nature exists in itself, and man is only part of it.
- Nature is legal (satisfies laws) and legality is causal (there is no objective hazard).
- Reality can be known little by little, although never perfectly.
- Science moves from diversity to unity, from the subjective to the objective, and from the relative to the absolute.
At present it is known that there are scientific laws, both causal as well as probabilistic or stochastic. Hence, in the concept of scientific law should be considered both types of law (deterministic and stochastic). One could extend the foundations of Planck’s science and propose the following (tacitly accepted by the majority of scientists):
- Everything that exists is governed by natural laws.
- These laws are invariant in time and space.
- The activity of the scientist consists in describing them.
- The existence of these laws is independent of whether the human being describes them or not.
- It is possible, in principle, to know the totality of the laws.