Types of Logic

Why Should I Care?

Your understanding of a social problem depends on the type of logic you are using. The earthy – got both their feet on the ground – scientists would prefer an inductive approach. The distant – rather be in an office or a laboratory – scientists usually prefer a deductive approach. Both have advantages and disadvantages.

This lesson has 5 parts

• Definitions
  
• The Process of Inductive Logic
  
• The Process of Deductive Logic
  
• Generating Hypotheses
• Archetypes and Stereotypes

What are Types of Logic?

When a student writes a research paper, they usually are thinking in terms of an essay, using a handful of arguments, and a good number of documents to support their thesis.

The instructor grading the paper will expect the paper to make sense, to be logical. Generally speaking, the term logic refers to deductive logic, which is a philosophical process whereby your conclusions are tested against your premises, your arguments, and your deductions. This type of logic is the basis for mathematics. Mastery of deductive logic will impress your readers, that's for sure. 

There is however another type of logic used in social science, the inductive method, which is just as useful. You might not have heard of it yet, but it is not very complicated. Inductive logic is based on observations, not arguments. It's conclusions are likely, but not as hard-set as the guarantees you get from conclusions from deductions. Inductive thinkers tend to be interested in complex phenomenon, where many variables are intertwined, and obvious outcomes are not possible. This is the caseuseful for understandunderstanding the history of war, family psychology, or the economics of complexity.

The field of physics has been the theatre of a complicated debate rooted in the use of these two opposing types of logic. This debate is illustrated between the intertwined relationship between Albert Einstein, and Robert Oppenheimer (Schweber, 2010).

Einstein can be considered a true deductivist. His theory of relativity is steeped in the importance of certitude, provided by the strength of deductive mathematics. When Einstein concluded that E = mc², he left no room for other possibilities, or probabilities. Oppenheimer can be considered more of an inductivist. The basic principle of quantum physics, of which he was a proponent, is that an object can present the characteristics of a wave, and of a particle, simultaneously. This theory is difficult to marry with the certitude of mathematics, and relies on probabilities.

• Definitions

Rational Thought/Logic
The ability to argue a point in a very strict manner.

Inductive Logic
From observable parts you build an unknown whole. Based on observations it leads to probable conclusions.

Deductive Logic
From the known whole you deduct known parts to uncover unknown missing parts. Based on assumptions and deductions, it leads to guaranteed conclusions.

• The Process of Inductive Logic

Inductive reasoning starts with observations of particulars and tries to make sense of them, by drawing a probable conclusion. Conclusions are likely, but not guaranteed. Researchers then go to empirical work to confirm the insights.

Inductive reasoning is akin to building a whole from the parts that are observable. This is useful when the whole object is unknown. If you find all the parts, this can be very helpful. However, if any of the parts are missing, you run into problems. There isn't a list of parts to start with, and you will never know if you found them all.

Observations
The scientist observes several facts, such that
A + B + C + D

First prediction
Given the observations, and the sum of the observations, the scientist may be convinced to predict an outcome, such that
then probably X, but maybe not

Second prediction
The first prediction may lead to a second outcome
then probably Z, but maybe not.

Example: This girl is A slim, B tall, C has blonde hair, and D her teeth are straight.
                She is probably pretty, and probably going to marry an attractive male.

                 (The girl could also be ugly, or not straight, or prefer ugly men)

Advantages
Rooted in truthful real-life observations. Allows for a very descriptive approach. Depth, and holism.

Disadvantages
The observations make the conclusion likely, but not guaranteed. This method is not sufficient for courts of law in democratic states. Just because some walks and talks like a thief is not enough to have them jailed.

Disciplines of choice
Sociology, Psychology, History, Anthropology

• The Process of Deductive Logic

Deductive reasoning starts with a premise, may add assumptions, and deducts a single outcome. The process is in fact a thought experiment. The researcher must then do empirical work to see if this logic holds in a real-life setting. 

Deductive reasoning is akin to subtracting parts from the whole. This works if the whole object is known, and if some of the parts are known. You can then deduct what the missing parts are by subtracting the known parts from the whole. It usually is very difficult to proceed with deductions if you don't have a good grasp of what the whole object is.

Premise
The scientist starts with a premise, which may be a value statement, a preference, a fact or an observation. The premise is often a statement that defines the whole object.
if A + B make the whole

Assumption
The next step is to make assumptions, often times to simplify the deductive process and avoid other factors from interfering.
assuming that F and G are unchanged

First deduction
To deduct is to take a part out of the whole. It is possible to deduct if a part's size or existence is known.
and B must be taken out

Conclusion
Then what's left is ALL that's left. The deduction allows one to see the missing part.
Then A is the only part left.

Example: The soccer game is on either Thursday or Friday. (A + B)
                 Assuming it won’t be on Friday because it’s a holiday. (minus B)
                 The game must be on Thursday. (A is left)

Advantages
Rooted in hard logic. When it works, it allows for a single conclusion. Used in courts. Used in simulations, and models. The logic is clear, transparent and very convincing.

Disadvantages
Strong assumptions are often needed to single out a conclusion. Conclusions may be completely opposed to real-life observations.

Disciplines of choice
Economics, Mathematics

• Generating Hypotheses
  

There are times when scientists have a distinct preference for either inductive or deductive reasoning. On one hand, do not be surprised if an anthropologist, after studying a culture for decades, tells you it would be impossible to predict a group's particular reaction to the proposal of a mining project. The anthropologist's work was not designed to predict a specific causal relation. Their work may nonetheless be quite useful, and might guide others in how to approach the group in question. But the social science work was never meant to deliver hard conclusions.

On the other hand, do not be surprised if an economist's work is mainly rooted in deductive modelling of the economy. When a bank asks an economist for their prediction on the exchange rate, for example, it would not be useful to get an answer where the exchange rate could go either up or down, apparently because the system is too complex to analyze. Economists need to provide some clear and convincing answers or else banks will stop asking them for their insight.

This said, it is possible to use both reasoning processes in the scientific method. They don't need to be at opposite sides of the table.

The Hypothetico-Deductive Model

The hypothetico-deductive method is an approach to research in certain social science disciplines that begins with general theories about how things work. From this general view, a strict model is derived, which allows to write up testable hypotheses. This aspect is purely deductive, since it begins with general premises, assumptions, and ideas. It then works from them to more particular statements, hypotheses, about what the world actually looks like and how it works. In these hypotheses, scientists are trying to predict the implications of specific relationships between variables.

The hypotheses are then tested by gathering and analyzing data. The theory is then either supported or refuted by the results. Since these empirical results are themselves observations from the field, from real-life, they therefore are based in inductive reasoning. If the hypotheses are not supported by the data, then researchers must read the data, and try to figure out a new model to understand their problem. Hence, the inductive process guides a new set of deductions and new hypotheses.

The hypothetico-deductive model is interesting because it allows researchers to derive predictions about the world based on broad theoretical models, and reshape these models based on the knowledge they acquire through their observations. They also are not constricted to the limitations of either inductive or deductive reasoning.

• Archetypes and Stereotypes

Many of our heated political debates have to do with discrimination. The core of this issue has to do with Archetypes, and Stereotypes. Both of these types have to do with either inductive logic, or deductive logic.

Archetype
In philosophy, this is a general model representative of a group. In psychology, Jung defined archetypes as a universal symbol of a type, or as a person that serves as a model for the group. For example, Arnold Schwarzenegger my be seen as the archetype of a strong man.

Stereotype
In sociology, this is a belief that someone holds about the characteristics of the members of another group. Can be positive or negative. Can be resistant to new information and be generalized excessively. For example, there is a stereotype that Scottish men are frugal, if not penny-pinchers. Of course, this is a view held mostly by the English, not by Scots. An illustration of this is the character of Ebenezer Scrooge, the protagonist of A Christmas Carol, a novella published by Charles Dickens's in 1843.

Stereotypes and Archetypes are used by almost everyone in society. We use them to evaluate our peers, our neighbours and the risk that they pose to our well-being, our communities, our institutions, and our workplaces.

Stereotypes quickly become toxic social constructions when people use them to discriminate on the basis of a social grouping and its perceived characteristic. It is up to society to determine when a stereotype becomes immoral, and this determination may change over time. For example, tattoos have become widely accepted in society, when in the past they were indicative of untrustworthy individuals. However, neck and face tattoos still provoke stigma and discrimination.

Categorize the following statements as being archetypes/stereotypes, based on inductive/deductive logic, and being moral/immoral.

Statement	Archetype/ Stereotype	Inductive/ Deductive	Moral/ Immoral
Michael Jordan is the GOAT	Archetype	Inductive	Moral
Scottish Men are Notoriously Cheap	Stereotype	Inductive	Immoral
Irish Guys are Tough People	Stereotype	Inductive	Immoral
Qc average income is below Can average	Neither	Deductive	Moral
Uneducated Men with Gangster neck Tattoos Should Not Be Trusted as Babysitters	Stereotype	Inductive	Moral
Queen Elizabeth was a Model for British Women	Archetype	Inductive	Moral

References and Further Reading

Chapman, A. D. (2016) Scientific Methodology: The Hypothetico-Deductive Method. YouTube. https://www.youtube.com/watch?v=ATU27c4crq4

Hempel, C. (1966). Philosophy of Natural Science 1st Edition. Prentice Hall. http://www.thatmarcusfamily.org/philosophy/Course_Websites/Readings/Hempel%20-%20Philosophy%20of%20Natural%20Science.pdf

Schweber, S. S. (2010). Einstein and Oppenheimer, The Meaning of Genius. Harvard University Press. https://www.hup.harvard.edu/catalog.php?isbn=9780674034525 

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