SCIENTIFIC METHODS OF INQUIRYPresentor:

Sr. Jennifer R. Cuerdo, OP

MA Guidance & Counselling

St. Thomas on Critical ThinkingDr. Florentino T. Timbreza

INTRODUCTIONTwo basic rules dominate the whole

process of induction :1. Positive Principle - Whenever a

certain antecedent (condition) is present, a particular phenomenon always follows or occurs; thus, the said antecedent is the cause of the given phenomenon.

2. Negative Principle - Whenever a phenomenon occurs in the absence of a certain antecedent, this antecedent cannot be the cause of the phenomenon in question.

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These basic rules were given their classic formulations and more explicit expressions by British philosopher, John Stuart Mill, called Mill’s Methods of Inductive Inference.

The Five “Canons“ are known as:1. The Method of Agreement2. The Method of Difference3. The Joint Method of Agreement &

Difference4. The Method of Concomitant Variations5. The Method of Residues

DEFINITION OF TERMSa. Phenomenon - any event, occurrence,

happening or condition in questionb. Cause - anything that has a positive

influence in the occurrence of somethingc. Effect – anything that is produced (caused)

by some other being d. Antecedent – condition or circumstance

which exists before or at the same time with an event or phenomenon

e. Consequent – circumstance, event or phenomenon that follows from the concurrence or conjunction of some antecedents.

THE METHOD OF AGREEMENT

“If two or more instances of the phenomenon under investigation have only one circumstance in common, the circumstance in which alone all the instances agree is the cause or effect of the given phenomenon.”

- The application of the general rule that the only unchanging antecedent of a given phenomenon is probably the cause.

THE METHOD OF AGREEMENTDetermine the instances:

Instance 1 Instance 2Find-out the circumstances under each

instance.The circumstance which is common to all

instances in which the phenomenon under question occurs is probably the

cause.

THE METHOD OF AGREEMENT

For Example: Pedro, Jose, Juan and Pablo attended a party and after the meals, all of them developed indigestion.

- The indigestion is the phenomenon.- The instances are Pedro, Jose, Juan

and Pablo.- The circumstances (food eaten) were

rice, pork, fish, vegetable salad.

THE METHOD OF AGREEMENT

What is the circumstance common to all instances? The eating of the FISH – probable cause of indigestion.

Instances

Rice Pork Fish Vegetable

Salad

Indigestion???

Pedro Yes Yes Yes Yes Yes

Jose Yes No Yes Yes Yes

Juan Yes No Yes No Yes

Pablo No No Yes Yes Yes

THE METHOD OF DIFFERENCE“If an instance in which the phenomenon under investigation occurs, and in an instance in which it does not occur, have many instances in common save one, that one occurring only in the former, the circumstance in which alone the two instances differ, is the effect, or the cause, or an indispensable part of the cause of the phenomenon.

- The application of the general rule that a thing cannot be the cause of a phenomenon which is present when the phenomenon does not occur.

THE METHOD OF DIFFERENCEDetermine the instances:

Instance 1 Instance 2Find-out the circumstances under each

instance.If you have one instance that leads to a

phenomenon, and another which does not, and the only difference is the presence of a single circumstance in the first situation, it is the cause of the phenomenon.

THE METHOD OF DIFFERENCE

For Example: Maria and Juana attended a luncheon after which Maria suffered from food poisoning, but Juana did not.

- The food poisoning is the phenomenon.

- The instances are Maria and Juana- The circumstances (food eaten) were

rice, vegetable, oyster, pork adobo.

THE METHOD OF DIFFERENCE

What is the only circumstance that is different between Maria and Juana? It is that Juana did not take OYSTER - which is probably the cause of Maria’s food poisoning.

Instances

Rice PorkAdobo

Oyster

Vegetable

Food Poisoning

?

Maria Yes Yes Yes Yes Yes

Juana Yes Yes No Yes No

LIMITATIONS OF MILL’S METHODS• First, the rules presuppose that we have a list of candidate causes to consider. But the rules themselves do not tell us how to come up with such a list. In reality this would depend on our knowledge or informed guesses about likely causes of the effects.• The other assumption presupposed by these methods is that among the list of factors under consideration, only one factor is the unique cause of the effect. But there is no guarantee that this assumption always holds. Also, sometimes the cause might be some complicated combinations of various factors.