1a. The italicized words in the following propositions are predicables because they are affirmed of the subject:
(1) “This man weighs one hundred fifty pounds.”
(2) “A bird is a feathered biped.”
(3) “The earnest teacher is an indefatigable worker.”
(4) “Walking is the most beneficial outdoor exercise.”
1b. Underscore the predicables in the following:
(1) “All men are rational.”
(2) “Teachers must be just.”
(3) “Every form of unhappiness springs from a wrong condition of the mind.”
(4) “Calmness of mind is one of the beautiful jewels of wisdom.”
2a. To clarify our ideas it is an excellent plan to select a group of words belonging to the same genus with a view of defining them as simply and expeditiously as possible. As an illustration building may be selected as a genus. The word kind will suggest to us the species, such as dwelling, church, theatre, school, barn, bird-house, granary and smoke-house. Next it is necessary to discover the basis of distinction. This seems to be the use to which the building is put. Now we are ready for the definitions:
| Species | Genus | Differentia | |
| A | dwelling | is a building | where people live. |
| A | church | is a building | where people worship. |
| A | theatre | is a building | where people act. |
| A | school | is a building | where children are taught. |
| A | barn | is a building | where domestic animals, hay and grain are kept. |
| A | bird-house | is a building | designed for birds. |
| A | granary | is a building | where grain is stored. |
| A | smoke-house | is a building | where meat is smoked. |
2b. By selecting man as the genus, define the terms Caucasian, Mongolian, Ethiopian, Malay and American Indian. Treat the term chair in the same manner.
3a. One may easily distinguish a property from an accident by asking himself the question, “Would subtracting the attribute from the term alter its identity”? For example in the following, I find that the words italicized are properties because subtracting each from the term changes its identity:
| Term | Attributes |
| man | age, rationality, possessions. |
| book | binding, leaves, size, color, contents. |
| radium | emits intense light and heat, costs a million dollars a pound. |
| snail | air-breathing mollusk, moves slowly. |
| slush | soft mud and snow, six inches deep. |
3b. Indicate the common attributes of the following terms, underscoring the properties: Tree, teacher, garden, house, river.
4. The rules summarize well the essentials of the subject matter of the logical definition. Therefore, it is highly important for the student to have these rules at the “tip of the tongue.” With this in view a device of this nature may be helpful. Make each letter of the word rules stand for the initial letter of a suggestive word in each of the five rules. For example: r (repeat), u (unambiguous), l (language affirmative), e (essential), s (same size).
With a little study “r and repeat,” “u and unambiguous,” “l and language affirmative,” “e and essential,” “s and same size” may be firmly linked together in the memory. Repeat suggests the third rule, do not repeat the name, etc.; unambiguous, the fourth rule, not ambiguous language, etc.; language affirmative, the fifth rule; essentials, the first rule; same size, the second rule, subject and predicate must be of same size. The fact that the rules are not recalled in order of treatment is inconsequential.
It is the writer’s experience that fifteen minutes of concentrated study upon this device or one similar to it will indelibly stamp upon the mind these troublesome rules.
The student may be able to devise a more helpful keyword.
(1) Why should the subject of definition appeal strongly to the school teacher?
(2) Define a predicable.
(3) Name in order the five predicables.
(4) Define and illustrate the terms genus and species.
(5) Explain the terms summum genus, infima species, sui generis.
(6) Illustrate proximate genus.
(7) Explain the terms genus and species as used in natural history.
(8) Exemplify the double meaning of the genus man.
(9) Define and illustrate differentia.
(10) In what sense is the species a richer term than the genus?
(11) Distinguish between property and accident.
(12) Illustrate separable and inseparable accidents.
(13) Give descriptive definitions of the following, indicating the five predicables: logic, general term, non-connotative term, obversion.
(14) Define definition; illustrate.
(15) Distinguish between definition and division.
(16) Name, define and illustrate the three kinds of definitions.
(17) Distinguish between real and verbal definitions.
(18) Define in three ways the following: king, government, city, metal.
(19) State the rules of logical definition.
(20) What words may be used as cues to aid in recalling the rules for logical definition?
(21) Under what circumstances will the wise teacher make use of each of three kinds of definitions?
(22) Relative to the second rule for logical definition what are the three questions that one should ask himself?
(23) Explain the exceptions to the third rule.
(24) In connection with the fourth rule what may be said as to the use of technical terms?
(25) What facts take from the force of the fifth rule?
(26) What classes of words do not admit of logical definition? Illustrate.
(27) Define education, teaching, instruction, training.
(28) Distinguish by illustration between induction and synthesis; deduction and analysis.
(1) Why should the scholar be tempted to speak and write illogically?
(2) Name the parts of speech that may be classed as predicables.
(3) Explain the ten categories as given by Aristotle.
(4) Show that genus and species are relative terms.
(5) Why should the definition be needed most in the abstract sciences, such as theology, ethics, political economy, juris-prudence and psychology?
(6) Define sin, life, wrong, personality, habit, character.
(7) From the viewpoint of natural history find the species in the series of terms of which polygon is a member.
(8) What is the plural of differentia?
(9) Why should logic insist upon the proximate genus?
(10) (a) Man is a rational animal.
(b) Man is a rational biped (proximate genus).
In the case of the immature mind the first definition would be clearer. Why?
(11) “A property of a term is any mark or characteristic which belongs to that term.” Is this definition logical? Give reasons.
(12) What is the difference between the logical and the popular conception of property?
(13) Is there any difference between the logical and popular conception of accidents?
(14) “The term conferentia might be used to stand for the essence of the genus, as the term differentia represents the essence of the species.”6 Explain this.
(15) John Stuart Mill affirms that there is no such thing as a real definition. Discuss this.
(16) In your opinion, of the five rules of logical definition what one is violated most by the average teacher? Give reasons.
(17) Distinguish between symbol and content.
(18) Why are descriptive definitions best for young children? What educational principle is involved?
(19) From the standpoint of the five rules for logical definition criticise the following:
(1) A man is a reasonable vertebrate.
(2) A gentleman is a man with no visible means of support.
(3) A man is an organized entity whose cognitive powers function rationally.
(4) A metal is an element with a metallic luster.
(5) A triangle is a figure of three sides.
(6) A teacher is one who imparts knowledge.
(7) Education is the process of drawing out all that is beautiful in the body and noble in the soul.
(8) A democrat is a man who believes in free trade.
(9) A government is a commonwealth controlled by direct vote of the people.
(20) Write the foregoing definitions in logical form.
(21) Since man is the only animal given to laughter, why is not the following a logical definition: “Man is a laughing animal.”
(22) “A logical definition should contain the species, the genus and the appropriate differentia.” Is there any reason for using the term appropriate?
(23) In connection with genus and species explain subaltern.
(24) Is laughter a property of human being or an accident?
(25) Show how a pedagogue may be an instructor but not a teacher.
(26) Illustrate the complete method.
(27) Show that induction may consist of a series of analyses; also a series of syntheses.