Inferential inductive fallacies arise when the rules of induction are violated. We have discussed three important types of induction like scientific induction, induction per simple enumeration and analogy.
Each of them is governed by certain rules. If any rule is violated there will arise some fallacy. Corresponding to these forms of induction there are fallacies of causation, illicit generalization and bad analogy.
A. Fallacies of Causation:
Cause, we have discussed, is the sum total of all conditions, positive and negative, taken together. Scientifically cause is also the invariable, unconditional and immediate antecedent from the qualitative point of view. When an unscientific view of cause is taken there arises the fallacy of causation. There are various kinds of causal fallacies. We shall discuss some important kinds.
i. Post hoc ergo propter hoc:
Cause is an invariable antecedent but to take any antecedent of a phenomenon as the cause will give rise to the fallacy of post hoc ergo propter hoc. It literally means, ‘after this, therefore because of this’. B occurred after A, therefore B must have occurred because of A.
To think in this way is to commit this fallacy of post hoc ergo propter hoc. Any antecedent is not the cause of a phenomenon for it does not confirm to the condition of invariability or unconditionally. This fallacy is the source of many suppositions because here no distinction is mode between variable and invariable antecedents.
Someone saw a dead body while going to his business establishment. On that day he incurred some loss in business. If he thinks that his loss is due to his coming across a dead body he commits this fallacy of post hoc ergo propter hoc. Or suppose a comet appeared and after two days a national leader died. If the appearance of the comet is considered to be the cause of death of the leader there will arise this fallacy.
ii. Fallacy of mistaking a condition to be the whole cause:
The cause is the sum total of positive and negative conditions. If one condition is exclusively taken as the whole cause of the phenomenon, this fallacy will arise.
For example, a student failed in the examination. If stiff valuation is considered to be the cause of his failure the reasoning will be fallacious. Because other conditions like his negligence in studies, insincerity in attending his classes, lack of intelligence etc. are omitted.
Similarly if we say that tribals are poor because they live in villages we commit this fallacy. Here we concentrate on one condition and ignore other conditions like lack of opportunity, exposure, education, social awareness etc. This fallacy is a very common one in practical life.
iii. Fallacy of non-causa pro-causa:
It means taking any circumstance to be the cause, which is not really the cause. It is like taking a false cause to be the cause. Aristotle illustrated this fallacy in the form of reduction and impossible. Here the conclusion is something absurd and such absurdity lies in the very assumption of the premise itself.
Aristotle’s introduction of this fallacy was not considered to be an inductive fallacy. But in modern logic this fallacy is used in a generic sense to connote any causal fallacy. Any fallacy arising in the sphere of causal inquiry is termed as non-causa pro-causa.
iv. Fallacy of ignoring the negative condition:
A cause is constituted by positive and negative conditions. The effect follows when the positive conditions are present and negative conditions are absent. But sometimes negative conditions are ignored and full emphasis is given upon a positive condition. Hard working is meaningless as many hard working people are deprived of the basic requirements of life. Here we are ignoring the negative conditions like exploitation, unfavorable social situation, lack of scope etc.
v. Fallacy of mistaking a remote condition to be the cause
The cause is the unconditional and immediate antecedent. If a remote cause is considered as the cause of the phenomenon under consideration, there arises this fallacy. An antecedent that happened in the remote past cannot be the cause of the effect that takes place at present.
For example, a person’s committing a crime at young age is attributed to his uncared childhood. A person might have been uncared in his childhood, but there are other intervening conditions without which he would not have committed a crime at the young age.
vi. Fallacy of supposing the co-effects of a cause as cause and effect.
Different effects might follow from a single cause. If we regard one of the co-effects as the cause of the other effect, we commit this fallacy
Day and night are so related that one follows the other. When we find them to be occurring successively the preceding co-effect is considered to be the cause of the succeeding co-effect. That means day is regarded to be the cause of night and night is regarded as the cause of the day. But day and night are not causally related, i.e. one is not the cause of the other.
On the contrary they are the co-effects of a common cause such as rotation of the earth round the sun and its own axis. Similarly suppose a person suffers from high temperature and vomiting. May be they are the co-effects of some other cause and one is not the cause of the other. But to take one symptom to be the cause of the other symptom is to commit this fallacy.
vii. Fallacy of supposing the effect to be the cause and the cause to be the effect
If we take a cause to be the effect and the effect to be the cause, we commit this fallacy
Sometimes a person’s recognition is considered to be the cause of his achievement. But his achievement is the cause of his recognition. When cause and effect are confused and reversed this fallacy is committed.
B. Fallacy of illicit Generalization
This fallacy is committed when we wrongly generalize only observing a few instances. Induction per simple enumeration is based on uncontradictoriness of our experience.
The probability of the conclusion depends on the number of positive instances. But hasty generalization on observation of a few instances or some stray cases leads to this fallacy of illicit generalization. That means when generalization is made by observing a few cases in a very limited sphere there is the possibility of committing the fallacy of illicit generalization.
A person has seen cows in his village to be white. If he generalizes that all cows are white, there is illicit generalization. Or suppose a man comes in contact with a few persons who are otherdox and put on saffron dresses. So he generalizes that all otherdox people wear saffron dresses. This is another example of illicit generalization.
C. Fallacy of False Analogy
Analogy is a kind of probable inference based on similarity. It is an inference from one particular to another based on their resemblance. In a false or bad analogy the points of difference and dissimilarity are more in number and importance.
In a bad analogy there is no relevant link between the data of comparison and the point that is inferred. For example, two persons come from the same village and belong to the same age group. One of them is an engineer. If we infer that the other person is also an engineer, it will be a case of false analogy.
Fallacy of false analogy, otherwise called bad analogy, has been discussed in the contexts of bad analogy and uniformity of nature.