Defects in Reasoning
So far we've seen several cases, where the power of inference was brought out. An important step in the process is stating the reason for our inferential knowledge. For example, while proving the existence of fire in the mountain, smoke was the reason. But the mere presence of smoke is not sufficient to prove the existence of fire. We should also prove that the presence of smoke establishes the presence of fire. As already stated, this relationship between the reason and the thing to be proved is called Vyapthi. This Vyapthi is shown by citing the example of hearth.
If, either the reason, or the Vyapthi is wrong, the whole process will lead to an erroneous result. For example the argument
'Today is a full-moon day, because it is bright'
will lead to an erroneous conclusion.
To avoid such erroneous conclusions, 'Tarka Shastra' has listed several types of defective reasoning. What is the need for such a classification of defects? Consider an argument between two persons. There must be a common meeting point between these two people. They must agree upon a set of rules. If they don't, then one of them can indulge in a meaningless talk, and insist that what he says is correct. To avoid that, certain types of arguments are considered to be flawed.