Inductive Logic

The first area of logic we will evaluate is inductive logic which is reasoning from particular facts or individual cases to a general principle.  A large part of science is based upon inductive logic and we will use science as an example when analyzing inductive logic.  Science gathers particular facts from around the world and even across our universe and is able to deduce general principles of how the natural world operates.  A good illustration of inductive logic is Newton and the law of gravitation.  Newton took observations of the planets in our solar system revolving around our sun and observations of the tendency of all objects on earth when thrown into the air to return to the ground and used these seemingly disparate observations to formulate the general law of gravitation that applies to all these phenomena.

The power of inductive logic is evidenced by the fact that through science we are able to understand how our material world functions which has enabled us to develop our technology.  Our technology has transformed human existence.  It has fed the hungry by increasing the yield of our crops.  It has healed the sick.  In fact, as Gopi Krishna points out, science has done more to heal the sick by eradicating diseases such as small pox than all the religious mystics and saints over the ages who performed healing miracles. [1]  Many of us owe our lives to the advances made in medical sciences.  Science has enriched our lives by enabling us to experience so much more than our ancestors through advances in transportation and communications.  We are able to travel and communicate easily worldwide; we are able to transmit pictures and information across our solar system and beyond.  Science has enabled us to invent all manner of labor saving devices that give us leisure time to do what we want, not what we must.  Science has, together with philosophy, given us a method of determining what is true and what is not.  The scientific method of developing a hypothesis, testing that hypothesis, revising the hypothesis based upon test results, and then repeating the process sharpens our thinking.

But inductive logic has its limits just like human experience.  The Webster’s New Universal Unabridged Dictionary defines inductive logic as “any form of reasoning in which the conclusion, though supported by the premises, does not follow from them necessarily”.  Under deductive logic it further expands on what inductive logic is:  “the truth of the conclusion is verifiable only in terms of future experience and certainty is attainable only if all possible instances have been examined”.

An example of the limits of inductive logic is give by the scientist Carol Cleland when she notes that we can never prove that all copper expands when heated because we cannot test all copper. [2]  We cannot go one million years into the future or one million years into the past to verify all copper behaves the way it does today.  The French scientist Henri Poncairé notes when scientists conduct an experiment, they can never be sure that a later experiment will produce the same result.  It can be highly probable but it cannot be absolutely proven. [3]  The philosopher Karl Popper maintains the laws of science transcend experience but our science is based upon experience (experiments) [4]  and as we have seen in the past two chapters, human experience has its limits.   The philosopher David Hume states we cannot prove that what we have not experienced resembles what we have experienced. [5]  Scientists cannot assume that experiments performed in the future will resemble experiments they performed today.

Also, we cannot be positive that the scientific experiments we perform on our world would be identical to one performed in another place in the universe.  Where and when we perform our experiments can matter.  Popper gives an example of the scientific law that the sun rises every 24 hours.  This seems like a scientific law but if we go north of the Arctic Circle, we will find that in the summer the sun never sets and in the winter it never rises. [6]  It is a firmly established fact the further science goes from the present time and location, the less certain science is.

Scientists could argue that we do have methods of looking into the past to verify what happened then.  Science can observe ancient events in the fossil record and look back in time via astronomy.  The problem with this approach is that the number of events we have observed is so infinitesimal compared to all the events that have occurred; we have not examined all possible incidents.  We cannot know if additional observations will produce a different conclusion.  It was not that long ago scientists believed that catastrophes played no part in the evolution of life on earth (uniformitarianism).  The information the scientist lacked back then was evidence the earth has been hit by asteroids and comets several times in its past.  What other information will we discover in the future which will change our view of our world and the universe?

Inductive logic fails because we humans are limited in space and time.  We cannot travel to all parts of the universe to verify our conclusions are valid everywhere.  We do not have sufficient time and resources to gather all the facts we need to validate our conclusions.  We must agree with Trueblood who states that inductive logic “has no perfect right to its conclusion”. [7]


[1]   Gopi Krishna, Living with Kundalini (Boston:  Shambhala, 1993), p. 328.

[2]   Carol E. Cleland, “Historical Science, Experimental Science, and the Scientific Method”, Geology, Vol. 29 (November 2001), pp. 987-988.

[3]   Henri Poincaré, The Foundations of Science (Lancaster, PA:  The Science Press, 1946), p. 96.

[4]   Karl Popper, Conjectures and Refutations (London:  Routledge Classics, 2002), p. 71.

[5]   David Hume, A Treatise of Human Nature (London:  Penguin Books, 1969), p. 137.

[6]   Popper, p. 68.

[7]   David Elton Trueblood, General Philosophy (New York:  Harper & Row:  1963), p. 107.

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