University of Macau
Philosophy and Religious Studies Program
PHIY 102: INTRODUCTION TO LOGIC
2nd Semester, 2015/16
Mondays, 16:00 18:45
Instructor: Dr. Mario Wenning
Truth tables can be used with single statements and
1. The complete truth table shows all the
truth values of an argument, and shows whether the
argument is valid or invalid.
2. The shortcut truth
Predicate logic allows us to look more deeply
into the analysis of statements than does
Predicate logic analyzes the subject/predicate
relationship to represent the inner structure
Examples: All geese are birds.
No pelicans are geese.
Some boats are arks.
Some days are diamonds.
All of the above examples are categorical
(The preceding statement is also a categorical
Chapter 7: Categorical Syllogisms
A categorical syllogism is a type of argumentso it is ne
cessary to clearly distinguish the premises from the con
Indicator words are helpful in correctly identifying the c
onclusion of a categorical syllogism.
A category is a group of things indicated by a noun.
Classification of things into categories is a key way of
conceptually organizing the world.
Words, particularly nouns, may refer to categories or
groups, which is to say th
Propositions: A proposition can be evaluated
as true or false.
Propositions are the units of thought, and are
typically expressed in sentences.
Sentences involve the subject/predicate
Sometimes we reason and argue about issues
based on our direct observations or
In other cases, we reason and argue about
issues that go beyond our direct observations
Reasoning with Propositions
Fallacies are mistakes in reasoning.
There are formal and informal fallacies.
This PowerPoint presentation focuses on the
As you examine fallacies, keep these points in mind:
Definitions aid us in clarifying our concepts and
making them more precise.
Definitions help us know what is and what is
not included in a concept.
We may expand our knowledge by adding new concepts, base