Causality is defined as the relationship between an event (known as the cause) and a second event (known as the effect), where the second event is a consequence or a follow up of the first. Causality has been a topical problem of discussion since the beginning of western philosophy.
Many philosophers tried to explain cause and its effects by showing how they relate to each other. Aristotle for instance, distinguished between accidental (cause preceding effect) and essential causality (one event seen in two ways). Aristotle example of essential causality is typified in a builder building a house. This single event can be analyzed into the builder building (cause) and the house being built (effect).
Aristotle, who regarded science as the search for cause, postulated four causes which provided the framework of explanation. These four causes were the four general types of answer to the question “why” or “why is something what it is?”
The first is the efficient cause (causa quod) or that by which a change is produced, the second is material cause or that in which a change is wrought, the third is final cause or the end for which a change is produced and lastly formal cause or that into which a change takes place.
Causality as postulated by Max Born (1949) implies that there are laws by which the occurrence of an entity B of a certain class depends on the occurrence of an entity A of another class, where the word entity means any physical object, phenomenon, situation, or event. A is then called the cause, while B is the effect.
For Max Born, antecedent cause implies that the cause must be prior to, or at least simultaneous with, the effect. In other words, the antecedent cause implies that the cause must happen before the effect or together with the effect.
Scientist has tried to set up experiments to determine causality in the physical world using the scientific method. But then, many scientists disagree that experiment are necessary to determine causality.
For example, the link between smoking and lungs cancer is considered proven by health agencies of the United States Government, but experimental methods were not used to establish that link. This view has been controversial and consequently, many philosophers prefer notions of causality that are more relativized.
Nature of Causality
The importance of causality lies in the fact that the universe is compactly full of events. Again, the explanatory models depend on the nature of the events to be explained, the culture in which it is being explained and the personal interest in that event.
Causation is therefore based on the fact that nature is uniform and the uniformity of nature implies that the same kind of cause produces the same kind of effect always and everywhere under the same condition.
This nature of causality based on the uniformity of nature presupposes that the universe is governed by natural laws. This is why we have laws in the natural science such as the Charles law, Boyles law etc.
It is from these laws of science derived from the natural law that theories of explanation or hypotheses are formed. For instance, Charles law states that at standard pressure and temperature, water will boil at 100°C in Nigeria.
However, it must be noted that it is not any kind of cause that can produce any kind of effect. Naturally only certain kinds of effect are produced by certain kinds of cause because the universe is not chaotic but an orderly cosmos. The universe is governed by laws and things happen according to these laws. What scientist does is to understand these laws on which to base their theories, so as to know the kind of cause that can produce certain kinds of desired effects.
The concept of causality is also associated with necessary connection. It was generally believed that there is a necessary connection between an event and its cause such that once the cause is present, the effect will necessarily follow.
The truth of this is that there will be no instances in which a cause occurs without a corresponding effect. For example, it was a common belief that lightening is the cause of thunder and that any time there is lightening; there must be a corresponding thunder.
But today this belief is quite erroneous as experience has shown that lightening do occur without the corresponding thunder. David Hume rightly noted that we do not perceive any such necessary connection; that it is part of our empirical experience.
However, Hume’s objection raises some question: if we perceive causality in our empirical experience, how then do we come to form the idea in our mind? The answer is not farfetched, for Hume’s explained that it is derived from our habit of association, which is associating things that go together in sequence.
According to Hume, the uniformity of nature on which the universality of causal principle is based is an assumption which cannot be proved. Similarly, that the future will resemble the past is an unproven assumption and all these assumption are implied in the universal application of the principle of causality.
The denial of any intrinsic or necessary connection has various implications. First it affects our idea of the laws of nature which shows that there is a necessary connection between a cause and its effect.
Secondly, the denial of necessary connection implies that the laws of nature are mere statements about the regularity and constancy with which certain things happen under similar conditions so that certain things necessarily follow others.
What this implies is that it is possible for things to fail to happen the way they have always been happening in the past on the bases of our empirical experience.
Another aspect of the nature of causality is that a cause generally precedes its effect in temporal order. This however, does not explain the non temporal order. But then there are certain cases in which both the cause and the effect are contemporaneous.
For example, when I write, it is my hand that causes the pen to write. In natural science, it is just the pen that causes the writing. But the theoretical sciences consider other interior causes such as the thoughts and the brain as well that function together to cause the hand to write.
Some philosophers who strongly uphold the priority of causes to their effect do that on the basis the causes have the power to compel the occurrence of effect.