Becoming a good critical reader means that you are able to logically evaluate the claims of the writer. Any writer would want the reader to consider—and possibly agree with—the claims that he or she puts forward. In expository writing, assertions become the primary channel for a reader to assent to a claim.

Assertions are declarative sentences that claim something is true about something else. Simply put, it is a sentence that is either true or false.

Read the following examples:

• The sampaguita’s roots are used for medicinal purposes, such as an anesthetic and a sedative.
• The sampaguita belongs to the genus Jasminum of the family Oleaceae.
• The popularity of sampaguita flowers is most evident in places of worship.
• Sampaguitas are the most beautiful and most fragrant of all flowers.

There are four common types of assertion, which are classified according to the degree of certainty they can be judged as true or false. How would you classify the previous statements?

Assertion of Fact

The first type of assertion is a fact. This is a statement that can be proven objectively by direct experience, testimonies of witnesses, verified observations, or the results of research. Because statements of fact can be double-checked for accuracy, there is general agreement about the truth they posit.

The sampaguita’s roots are used for medicinal purposes, such as an anesthetic and a sedative.

This statement is a fact because it can be directly verified by experience or reliable research reports.

Assertion of Convention

The second type is an assertion of convention. A convention is a way in which something is done, similar to traditions and norms. Conventions depend on historical precedent, laws, rules, usage, and customs. Thus, their truthfulness is verified by how commonly held definitions and beliefs are interpreted.

Something to note about conventions is that they may sound factual due to their being derived from customs, but because they are socially accepted ways of doing things, they cannot be verified objectively by measurements.

The sampaguita belongs to the genus Jasminum of the family Oleaceae.

This statement is a convention because it is based on a classification system made up by scientists and is acceptable to the scientific community.

Assertion of Opinion

The third type of assertion is an opinion. Opinions are based on facts but are difficult to objectively verify because of the uncertainty of producing satisfactory proofs of soundness. Opinions result from ambiguities; the more ambiguous a statement, the more difficult it is to verify. Thus, they are open to disputes.

The popularity of sampaguita flowers is most evident in places of worship.

The above statement is an opinion because it is based on an observation that needs to be proven by studies and repeated observation; there are too many factors involved that make explicit judgment difficult.

Assertion of Preference

The fourth type of assertion is a preference. Preferences are based on personal choice; therefore, they are subjective and cannot be objectively proven or logically attacked.

Sampaguitas are the most beautiful and most fragrant of all flowers.

This statement is a preference because it says a lot about the type of flowers that the writer likes, instead of objectively comparing the qualities of sampaguitas to those of other flowers.