The doctrine of plurality of causes is not an unchallengeable doctrine

1. Characteristic Imperfection:

This method fails to establish causal connection in, the case of plurality of causes. The doctrine of plurality of causes is not an unchallengeable doctrine.

But there are certain cases of observations where the factor responsible for the occurrence of the effect may differ and the notion of plurality of causes somewhat becomes accept able because of uncritical and simple observations.

For example, in some cases where people have suffered from headache and| have taken medicines bearing different names like Saridon, Aspirin, Oxalgin, Nise, etc. all of them have taken the medicine with water.

All of them have feft relief from headache. Since the medicines differ from case to case but water is the com­mon factor, as per this method the common factor water will be treated as the cause of relief from headache, which is not the case.

2. Practical imperfection:

When the fallacy of non-observation is committed in respect of this method it becomes a disadvantage for the application of this method. There can never be any guarantee that all the factors involved with the occurrence of the incident are observed.

It may so happen that some of the essential circumstances may remain unobserved. This defect is known as practical imperfection of the method. Instead of taking few instances if the observations of instances are increased, then there is the possibility of overcoming such a defect.

But this method may not be able to help in all the cases. For example, the scientists, so far, have failed find out the common factor of agreement in case of like diseases cancer where there is unusual cell-division. The common factor responsible for the unusual cell-division is not yet properly known.

3. It is not possible to distinguish cause from co-existence by this method. Just like the causal factor is found common in a number of cases so also the factors which co-exist are also found as common in a number of cases. Because of common agreement a factor which is commonly found as co-existing may be considered as cause on the same ground.

The lightning co-exists with thunder so one may think of a causal connection between them; lightning co-exists with thunder but is not its cause.

4. A condition or a part of a cause may be found as a common antecedent in a number of cases. In such cases that condition may be supposed as the cause because of the agreement in a number of cases. For example, the requirement of sour for the preparation of curd agrees in most of the cases. Sour is one of the conditions of curd but not the whole cause. Here there is every chance of confusing a condition to be the cause.

5. The applicability of this method fails in the case of conjunction of causes and intermixture of effects.

This method will not be useful to isolate the exact antecedent in case of conjunction of causes.

This method takes for granted that antecedents and consequents are distinguishable. But this is not really the case. For in some cases a joint effect may be the outcome of some conjunction of individual causes where it is not possible to isolate the effect of a particular antecedent.

Because of the above defects it is never possible to reach at a conclusive causal connection through this method.

It is always better to accept that this method can suggest a hypothesis, which is highly probable. So the causal connection established through this method is only probable in nature.