Deductive and Inductive Thinking, or Watch Out for Drivel!
When we make an argument for a proposition, we pull together many pieces of evidence and induce from that evidence a general conclusion. This is known as inductive (‘bottom-up’) thinking. Alternatively, we can make an argument for a series of outcomes, say, based on a generally accepted conclusion; this is the opposite to inductive thinking and is known as deductive (‘top down’) thinking. Both forms of thinking require a search for evidence (research) and a rational argument to make the case.
In philosophy, there are two weighty Latin phrases for these two forms of thinking. Inductive thinking is termed a posteriori which literally means ‘from what will come later’, that is from the yet to be proven general conclusion. Deductive thinking is termed a priori which means ‘from what was there before’, that is the already proven general conclusion. Science relies more heavily on deductive thinking because it seeks to build on what is already proven. Science figures correctly that it cannot take risks in this domain as it is dealing basically with material reality which may involve the safety of people’s lives. Once something is proven inductively from a great deal of research, peer review, and experiential learning, then it becomes a general conclusion which science can use to deduce other facets of knowledge.
An example of flawed inductive reasoning could be: a study in an undergraduate psychology course which uses undergraduates as its subjects, and where these subjects (the undergrads) may not be representative of the total population to which the study’s author wishes to generalize his/her results. The conclusion drawn may (will) be flawed as it does not sufficiently represent the truth for all people.
And a very famous example. Albert Einstein developed the Special Theory of Relativity in 1905 whilst working at the Patents Office in Bern. He did so inductively, using thought experiments towards a general conclusion. The General Theory of Relativity followed in 1915, similarly conceived. The scientific community could not take these theories as proof until they had been proven. WW1 had intervened but Arthur Eddington and his team used the total eclipse of 1919 (over Brazil and west Africa) to prove that light from distant stars can be ‘bent’ by the mass of a celestial body, in this case the Sun (Sol). Eddington’s results confirmed Einstein’s Relativity theories. Front page news around the globe. Einstein was immediately awarded the Nobel Prize for Physics in 1921. These theories are now generally held to be true and can be used by other scientists to deduce supplementary effects.
But we have a problem today. Too many people are taking their own set of experiences and inductively postulating them as a general conclusion – without doing the necessary research first. As few as two or three instances of a noticed phenomenon can be induced to mean a (faulty) general conclusion. The easy availability of social media enhances the allure of this faulty conclusion which can quickly ‘go viral’ causing many more people to consider the faulty conclusion, to the extent that they come to believe it to be so. ‘There is no smoke without fire’ they may say to themselves, and repeat the initial faulty conclusion, drawn by someone whom they have never met, as a matter of fact.
This is not rational nor scientific. It is dangerous. The tendency of humans to amplify their personal beliefs (fears?) into a large-scale system of belief, whether social, economic, political, legal, or environmental is harmful to all as it influences unduly our views of our lives. Harmful, as this influence causes us to regard the future in a different, less resilient, perspective. It may ultimately contribute to the creation of conspiracy theories and other generally held yet scientifically irrational beliefs, such as anti-vaccination proposals.
Let us think carefully before we utter lest we repeat drivel. Let us scotch unvalidated comments without further transfer. Let us develop the strength of character to say: ‘No. That is gossip.’