There are two kinds of reasoning: inductive and deductive. The difference between them is incredibly significant in science, philosophy, and many areas of knowledge.
Inductive and deductive reasoning are the two ways in which we think and learn, helping us to develop our knowledge of the world. It is easy to confuse the two, as there is not a huge difference between them.
Yet, they change the way that we reach a conclusion and therefore the reliability of the knowledge we draw from it. Reasoning helps us to reach logical conclusions from a hypothesis or experiment we conduct.
To know the difference between inductive and deductive reasoning, it is best to understand them in terms of examples.
Deductive Reasoning
Deductive reasoning is the most solid form of reasoning which gives us concrete conclusions as to whether our hypothesis was valid or not. When we use this form of reasoning, we look for clear information, facts, and evidence on which to base the next step of the process.
If all steps of the process are true, then the result we obtain is also true. This form of reasoning creates a solid relationship between the hypothesis and the conclusion so that we can directly apply a particular process.
Deductive reasoning is the kind of reasoning used in scientific exploration, as it gives a clear method and conclusion without any guesswork. This gives us an answer we can rely on and replicate at any time because the conclusion is always certain.
Examples of Deductive Reasoning
General Illustration:
- Premise 1: If 1=2
- Premise 2: If 2=3
- Conclusion: 1=3
This is the general formulation of deductive reasoning.
Philosophical example:
- Premise 1: Socrates is a man
- Premise 2: All men are mortal
- Conclusion: Socrates is mortal
Here we can see that the conclusion logically flows from premise 1 and 2.
Chemistry example:
- Premise 1: Noble gases are stable
- Premise 2: Neon is a noble gas
- Conclusion: Neon is stable
This is a real-life example that would be used in scientific exploration.
Inductive Reasoning
Inductive reasoning is the exact opposite of deductive reasoning because it does not rely on solid evidence to form conclusions.
When we use inductive reasoning, the propositions used are strong evidence for a certain conclusion, but a certain amount of guessing is necessary. By using inductive reasoning, we assume a certain conclusion to be true, but we cannot prove it definitively.
Inductive reasoning provides a basic and general understanding of how things work rather than a solid method and therefore cannot always be replicated. The conclusions of inductive reasoning may seem to be true at one point then the conclusion to be false. The conclusion can even be false if all the propositions are true.
This makes it difficult to use inductive reasoning in scientific exploration. Therefore, inductive reasoning is most used in real life reasoning rather than in science or fields where conclusions must be clearly valid.
Examples of Inductive Reasoning
Generalizing inductive reasoning
- Premise: All swans we have ever observed are white
- Conclusion: All swans are white
Although this is a strong inference, we cannot expressly rule out the existence of swans of any other color. This particular example was invalidated by the discovery of black swans in Western Australia in 1697.
Causal inductive reasoning
- Premise: Sarah leaves the house at 7.30 and she arrives late for work
- Conclusion: Sarah concludes that every time she leaves the house at 7.30 she will be late for work
This conclusion, however, does not always follow from Sarah leaving the house at 7.30. Sarah’s being late may depend on other factors such as traffic conditions or the weather. It does not always follow that Sarah will be late every single time she leaves the house at 7.30.
Statistical inductive reasoning
- Premise 1: You have 50 pens in front of you
- Premise 2: Upon checking the first 10 pens, 5 are red and 5 are green
- Conclusion: Half of the pens are red and half are green
This does not follow as there may be black or blue pens in front of you also, but you just happened to pick up red and green pens. Therefore, it may not be valid to make such an assumption on the color of some pens and not all.
Key Differences between Inductive and Deductive Reasoning
- Deductive reasoning depends on facts and evidence; inductive reasoning looks at patterns.
- Deductive reasoning provides solid, repeatable conclusions. Inductive reasoning makes general, most probable conclusions about evidence that has been observed.
- Inductive reasoning may not always have strong conclusions on the validity of its hypothesis. Deductive reasoning will always have strong conclusions as to whether the premise is valid or invalid.
Inductive and deductive reasoning are two important kinds of logic that we use in everyday life. They are very different from one another and therefore give different kinds of conclusions.
However, it is important to understand both to understand how we have come to a conclusion and the knowledge we obtain.
References:
I think it was Arthur Conan Doyle whose Sherlock Holmes wold say to Doctor Watson: “Simple deduction, Watson.”