This paper explores two types of reasoning; deductive and inductive reasoning. Deductive reasoning involves a hierarchy of truths whereby several simple statements are used to formulate a more complex statement. The simple statements used are called premises, and the formed complex statement is called the conclusion (Sternberg & Mio, 2008). In deductive reasoning the premises are general and the conclusion is specific. Inductive reasoning on the other hand involves making of general conclusions, from simple premises which are based on experiences, observations and analysis of these premises (Goswami, 2005). The papers also focus on various impediments in reasoning and the various ways through which reasoning can be improved.
Key words: Deductive reasoning, Inductive reasoning, Premises, Conclusions.
Reasoning: Inductive and Deductive Reasoning
In deductive reasoning, the conclusions are already contained in the premises even in implicitly (Sternberg & Mio, 2008). This means that in deductive reasoning we do not arrive at new information but we are shown information which was obscured or not recognized before. Inductive arguments provide us with new ideas and thus expand our understanding regarding the world in a manner that is impracticable for deductive argument (Goswami, 2005).
Failure of deductive reasoning
Last week I prepared for shopping. Normally I use about 1000 USD for my shopping in a month. In the newspaper, there was this advertisement that prices of various commodities had gone down by 8% in one of the supermarkets. So with my calculations, I concluded that my overall budget for the month will reduce also by 8% if I went shopping in that supermarket. Later when I calculated my total expenses for the shopping, I realized that I had used 1% more my normal budget. Then I knew that my previous deductive conclusions was actually wrong since I did not realize that the prices of gas had gone up so fuelling my car cost me more than I had anticipated.
Failure of an inductive reasoning
In my family we have a close family friend. This man is named Peter and is very rich. Around the city there are many estates where people live. One particular estate called Runda is known to be inhabited only by the rich people. Formally, I did not know where Peter lived so from his status, I concluded that he must be living in Runda. On the
contrary I came to know that Peter actually lived in one of the low class suburbs and I therefore realized that my inductive reasoning was incorrect.
Normally in deductive reasoning, the conclusion follows from the premises in that for the conclusion to be true then the premises from which it is formed, must also be true(Sternberg & Mio, 2008). In the above scenario the deductive thinking turned out incorrect because of various impediments. First cause was availability heuristic. Here I only depended on the information available in the newspaper that the prices of commodities had gone down without seeking further information that would have helped me to come up with a good conclusion. Secondary I was biased in that if I bought the commodities in that supermarket, then my expenditure would go down by 8%, not knowing that if I bought the same commodities at a nearby supermarket where I could walk, I could not have spent the money on fuel and so my expenditure could be low.
In inductive thinking the premises provide some clues about the conclusions which must not necessary be true (Sternberg & Mio, 2008). In the above scenario, distribution heuristic contributed to wrong conclusion, that because Peter is rich, and all rich people live in Runda, then he must live in Runda. Peter here being the sample among a population of rich people, does not represent all the characteristics of the rich, so because of distribution heuristic, my inductive thinking was wrong. Bias here is also seen in that thinking that only rich people live in that particular estate was not true. Same way that Peter did not live there means that other people who are not necessarily rich might be living in Runda. This is overconfidence, which is known to be the most serious of mental bias, since it seems amazingly resistant to evidence of our own errors (Goswami, 2005).
Failure of deductive reasoning, as illustrated above, can be avoided in several ways. First one should take time to evaluate the premises carefully and then form multiple mental models of the propositions and their relationship (Sternberg & Mio, 2008). Sternberg and Mio (2008) explains that training and practice in effective deductive reasoning is also of great help and making of conceivable conclusions which are useful in pragmatic perspective such as in social occasions.
Failures in inductive reasoning as described above, can be avoided by reasoning again the problem at hand, in a deductive manner (Goswami, 2008). This is because the conclusion obtained from the premises in inductive thinking is not always true. On the other hand, the conclusion inferred from the premises in deductive thinking is always true on condition that the premises are also all true (Sternberg et al., 2008). Therefore rethinking an inductive problem deductively will most likely lead to the proper reasoning.
There is a big difference between inductive and deductive reasoning. Inductive reasoning is more open minded and exploratory at the beginning. Its arguments are based on experiences or observations. Inductive reasoning is mostly used in fields of research (Goswami, 2005). Deductive thinking on the other hand is narrower in nature, and is concerned with testing hypothesis. Deductive arguments are based on laws rules and other widely accepted principals (Sternberg et al., 2008). They are mostly used in mathematics.
Stenberg, J.R., Mio, J. (2008). Cognitive Psychology. Wadsworth: Cengage Learning.
Goswami, U. (2005). Blackwell Handbook of Childhood Cognitive Development. Malden: Wiley Blackwell.