This document distinguishes between concrete and abstract ideas. Concrete ideas represent things as they exist in reality, like humans or animals. Abstract ideas consider attributes separately from the subject, like humanity or animality. Ideas can also be singular, universal, particular, or collective depending on whether they represent one item, a whole class, part of a class, or a class as a group but not individuals. The Aristotelian categories include substance, quantity, quality, relation, action, passion, time, place, posture, and habit. Predicables are different ways an idea can be predicated of a subject, such as species, genus, difference, property, or accident.

2.  We also distinguish between:
Concrete and Abstract
Ideas are concrete when they express a
nature or attribute inherent in a subject;
but when the ideas express an attribute
(considered by the mind) separate from
the subject upon which it inheres, they
are abstract.

3.  A concrete idea always represents a
thing as it is found in reality, such as man,
house, horse, cow, substance, etc. Or
the nature of white, small, tall short, etc.
 These ideas become abstract when I
consider them by themselves. Man is
always an individual but humanity is
abstract. White always inheres in a
subject but whiteness is abstract. Animal
is concrete but animality is abstract.

4.  Ideas are:
 Singular – when they represent a single
subject either by proper name or by
class. Ex. Jose Rizal, my mother, this pen
 Universal – when they represent a class
as a whole or each individual of that
class. Ex. Man, Every man, teachers,
every flower

5.  Particular – while singular applies to one
and universal applies to all in a class,
particular idea applies to neither of the
two but only to some or a part of the
whole.
 Collective – applies to all individuals as a
class but not to the single members of
the class. Ex. Army, library, flock, herd,
company

6.  The Aristotelian categories are ten in
number. They are: substance, quantity,
quality, relation, action, passion, when,
where, posture, habit.
 A substance is a being existing for and in
itself, needing no other subject in which
to exist. Ex. Dog, house, cat. It answers
the question: what is this thing?

7.  The rest are the modifications of the of
the substance (material or immaterial)
as it exists. They are also called
accidents. An accident cannot exist
unless it inheres in a subject.
 Let’s go over them one by one.

8.  Predicables are the different modes or
ways in which an idea can be
predicated of its subject.
 Species – expresses the whole essence of
the subject. Man is a “rational animal”.
 Genus – expresses a part of the essence
which it has in common with the others.
 Man is an “animal”.

9.  Difference – expresses a part of the
essence of the subject which
distinguishes one species from another of
the same genus. Man is “rational”.
 Property – expresses something which
flows necessarily from the essence but
not the essence of the subject. Man can
“cook” food.

10.  Accident – expresses something neither
of the essence nor necessarily
connected with the essence but
contingently connected with the
essence itself. Man has “two legs”.