If a fact appears puzzling and with the existing knowledge it is not possible to explain it, then an explanation is sought to make it plain and clear.
Hence a true explanation I of the facts, events etc. extend our knowledge. Man’s inquisitiveness along with search for a scientific explanation has expanded man’s intellectual horizon.
Though man’s inquisitive mind seeks explanation when he comes across a puzzling phenomenon all explanations are not scientific or reasonable. A scientific explanation is different from a popular explanation.
The former is very much dependable as it is in accordance with the I scientific procedure. But before going to discuss the nature of scientific explanation, some I popular or unsatisfactory explanations should be pointed out.
Human thinking has passed through different ideas at different times. In ancient I day’s people were satisfied with supernatural or mystical explanations.
They tried to I understand natural phenomena as the acts of some supernatural power. Natural events like I rain, eclipses, calamities, death, disease etc. were explained by fostering supernatural causes.
The belief that a natural calamity is due to the wrath of a deity or that the solar eclipse is I the result of a dragon’s swallowing the sun is not a rational one. Here there is no scientific I explanation. For a scientific explanation does not accept any supernatural cause or mystical I occurrence.
Scientific explanation accepts natural causes or laws whether they are known I or not. There are many facts which have not been explained in spite of great efforts.
Sol there is mysteries. What has been a mystery may be explained with new innovations and discoveries. But the possibility of there being some supernatural cause of a natural I phenomenon is quite incompatible with the very spirit of scientific explanation.
Similarly some explanations are unsatisfactory. They do not fulfil the basic requirements of scientific illustration. Any attempt to explain some phenomenon by bringing synonymous expression of the term referring the phenomenon does not serve any useful purpose. If one says that a mother takes care of her baby because she possesses a maternal instinct, then his explanation is unsatisfactory. Because it virtually gives no explanation except that it is not learned.
Similarly if one says robin is a migratory bird because it has migratory instinct, his explanation is unsatisfactory. For it does not say what a migratory instinct is or why robins migrate but not cuckoos or crows.
Teleological or purposive explanations are not considered as scientific explanations. Purposive explanations are accepted in case of actions of human beings. Behind an action of a person there might be some intention.
A student labours hard to secure a good rank in the examination. So the student has a purpose. But sometimes purpose is attributed in case of natural facts or events. Sun rise, sun set, rotation of seasons, rain, cyclone, blossoming of flower etc. are natural events which can be explained by natural causes.
To attribute some purpose to some agent or power in case of natural phenomena is not a scientific explanation. A purpose presupposes a purpose and no purpose is there in natural events. Descriptive laws of nature are not governed by any purpose.
In practical life sometimes explanations are advanced on the basis of similarity between two phenomena or situations. When two things are found similar on some points some explanation is given bringing their resemblance. But an analogical explanation does not serve a scientific purpose unless it is linked with some deep-seated points or law.
Suppose if it is said that death is nothing but like discarding a torn cloth, then there is no explanation of death. If it is said that when a cloth is torn, it is discarded, so also when the body is old or diseased it is discarded.
Before a phenomenon is scientifically explained it is necessary to categorize it by the process of classification. Classification means assimilation and discrimination as well. If there is a perplexing phenomenon which is beyond the scope of our known laws, then it is necessary to classify it.
To classify means to know its class pattern or its group-nature. When it is classified, it is also discriminated from the group of laws to which it does not belong.
Then it is assimilated. After assimilating it properly attempt can be made to explain it by help of some law or hypothesis.
Scientific explanation is systematic, methodical and mostly unified. Here facts are explained with the help of laws or regularities of nature.
While popular explanation is concerned with particular facts, scientific explanation brings facts under some established laws.
The explanation of facts, events, occurrences, processes etc. consists of reference to some law or uniformity of nature.
It begins its inquiry with the question “why something is the case?” why iron rusts, why lightning precedes thunder, why night is longer than day in winter etc. are events. Through explanation of events scientific explanation establishes general laws.
That means scientific explanation is interested to discover the causes behind these events. When the cause of a phenomenon is known, it acts like a law: Science unifies the unrelated facts and brings them under some laws.
Facts are explained by laws; laws are also explained by higher laws or theories. We have already explained it in the context of system in science. That holds it here also.
Thus any phenomenon is explained if it is taken to be the result of a law or me deducible from the law. In science laws make a coherent system and no law is an isolated generalization.
When a phenomenon is deduced from a law or the law acts as its explanation, then it is explained. Explanation thus consists of some propositions including a law from which the phenomenon or thing to be explained can logically be inferred.
Thus explanation acts as the premise and the fact sought to be explained as the conclusion. Since the law is probable upon which the explanation of the phenomenon depends the explanation will have probability only.
Every scientific explanation is in accordance with the scientific procedure that consists of some well defined steps. It primarily includes observation of facts, formation of hypothesis and its verification.
Basically an explanation is like a hypothesis, so the conditions that are required for a legitimate hypothesis also hold well in case of a scientific explanation. The evaluation of a scientific explanation depends upon some criteria. Sometimes there is more than one explanation for the same fact.
Even there may be different theories to account for a group of facts. Thus in such cases where incompatible or alternative explanations are present, it is necessary that explanations must be evaluated.
Evaluation of explanations, either as good or bad, or as better or worse, requires certain criteriological consideration. Some criteria such as relevance, testability, consistency with previously established hypotheses .explanatory power and simplicity are fixed for that. An explanation is not intended for its own sake but to explain some fact or other.
So it should be relevant to fact it intends to explain. That means the fact in question should be deduced from the hypothesis that is given as an explanation. Again the explanation must be in principle testable.
A hypothesis supposed to provide an explanation to a fact must be connected directly or indirectly with facts of experience. Any explanation must not violate a well-established hypothesis. Of course science gives progressive knowledge, so new theories sometimes shatter the old cherished ones.
Ordinarily a hypothesis need not contradict an established theory, but in face of incompatible theories, the theory that fits in better with the body of scientific laws is to be preferred. This implies the next point in the criteria i.e. an explanation must have predictive power.
The explanation advanced in favour of a fact not only should explain that particular fact but be like a law to explain all facts of that type.
That means the supposed explanation should have greater explanatory power. The greater the explanatory power, the more satisfactory is the explanation. An explanation which is more simple and not very complex and complicated draws attention.
It is of course difficult to define simplicity. But in case of two competing theories of explanation the simpler one is accepted.
Different logicians classify scientific explanation differently. We shall discuss Nagel’s classification as it presents a comprehensive form of explanation. Nagel classifies scientific explanation into four types. They are: