deductive vs. inductive

Inductive reasoning

Jennifer leaves for school at 7:00 a.m. Jennifer is always on time. Jennifer assumes, then, that she will always be on time if she leaves at 7:00 a.m.

Every windstorm in this area comes from the north. I can see a big cloud of dust caused by a windstorm in the distance; so, a new windstorm is coming from the north.

Bob is showing a big diamond ring to his friend Larry. Bob has told Larry that he is going to marry Joan. Bob has bought the diamond ring to give to Joan.

The chair in the living room is red. The chair in the dining room is red. The chair in the bedroom is red. All chairs in the house are red.

Murray Gell-Mann, a theoretical particle physicist who won the 1969 Nobel Prize in physics, used the specific measurements of multiple particles with varying masses to induce the existence of quarks, half of the known elementary particles – the foundation of all matter, and what he called the eightfold way, a generalization of particle symmetries, which was able to predict the masses of yet undiscovered particles.

Linus Pauling, a chemist who is the only person to win two unshared Nobel Prizes, for chemistry in 1954 and peace in 1962, charted particular chemical bond angles and distances at Caltech following his fellowship. He then used these specific charts to formulate generalizations about atomic arrangements in crystals.

Empirical

Inductive: Latin inducere, from in + ducere to lead. To induce means to: move by persuasion or influence; call forth, effect; cause the formation of. Inductive reasoning begins with observing particulars.

Should the particulars indicate a pattern, a conclusion might be drawn or inferred. The particular is the starting point. To infer means: to derive as a conclusion from facts or premise; guess, surmise; involve as a normal outcome of thought; point out, indicate, suggest, hint.

Deductive: Latin deducere, to lead away, from de- + ducere to lead. To deduce means to: infer from a general principle; trace the course of. Deductive reasoning draws a conclusion about particulars based on general or universal premises. The general is the starting point. A premise is something assumed or taken for granted, presupposed, believed.

Empirical: Originating in or based on observation or experience; relying on experience or observation alone often without due regard for system and theory; capable of being verified or disproved by observation or experiment. Latin empiricus, from Greek empeirikos, doctor relying on experience alone, from empeiria experience.

What is quality?

Deduktiv. Deductive. Latin deductivus, deductio. To base on, to continue. Deduction, or the deductive method, is defined in philosophy as arriving at specific conclusions based on assumptions or principles.

The Greek philosopher Aristotle defined deduction as „conclusions about the specific based on the general.“ Induction, or inductive thinking, is the opposite: arriving at general principles based on the observation of particulars.

Normen. Norms. Latin norma, the measurement of an angle; generally excepted rules of interaction among people; standards for size, weight, quality; the average value of something; minimum values of a thing or behaviour.

Qualität ist die Einhaltung von Normen. Quality is meeting all necessary norms. The response of a German engineer to the question „What is quality?“

Popper’s Principle of Falsification

Deductive thinking is to make conclusions based on a law and a condition. Students in the social sciences at German universities learn deductive thinking early on.

Applying deductive thinking in the social sciences is not that simple, however. Statements (laws) can never be proven conclusively, because it is not possible to test every possible case.

The Germans in the social sciences, therefore, rely on the Falsifikationsprinzip or principle of falsification: to seek out cases which contradict the hypothesis, in order to refine that hypothesis.

The Falsifikationsprinzip was developed by the Austrian philosopher Karl Popper, and is foundational to social science thinking in Germany.

It is one of the key reasons why Germans are inclined to reject inductive thinking, which suggests the general based on the specific. German social scientists (and academics in general) believe that inductive thinking is fine for everyday life, but has no place in the sciences.

Inductive thinking is inference. It is a generalized conclusion based on particular instances. American processes and procedures are arrived at more inductively, based on experience. Examples

Deductive vs. Inductive

Deductive thinking is by inference. The conclusion about particulars follows necessarily from general or universal premises. German processes are arrived at more deductively, based on standards and norms. Examples

Deductive vs. Inductive

German Approach

American Approach

Inductive thinking is inference. It is a generalized conclusion based on particular instances. American processes and procedures are arrived at more inductively, based on experience. Examples

American View

German processes are developed in a vacuum, are theoretical, too far removed from everyday business. Deduced from principles (standards and norms) they have a one-size-fits-all character, not taking into account the particulars of our market, of our customers.

German View

Americans don‘t gain sufficient distance from the details of their work to recognize certain patterns. The basis is not there for process optimization, an analysis of what is and is not working. Abstraction is required.

Advice to Germans

Explain your standards and norms, and how you arrived at them, your data and methodology. Most importantly, engage in a dialogue with your American colleagues about when the processes can be adapted to the „situation on the ground.“ Strive to understand the impact of processes on their reality.

Advice to Americans

Don‘t sit just back and criticize German processes. Step into their „process laboratory.“ Gain distance from what you do. Get abstract. Search out the deeper-lying principles governing how you do the work. Engage in the discussion of when to deduce from the principle, when to induce from the particular.