Personal observations are used to construct the foundation of a travel piece. Those who wish to be effective in convincing others of something need to have at least a basic grasp of logic. An argument is a sequence of statements together with a claim. The claim is that one of the statements, called the conclusion, follows in some way from the other statements, called the premises. An argument is correct when the claim that the conclusion follows in some way from the premises is justified.
Formal logic proceeds from the general to the specific.
It uses the general to prove the specific. Pierre is a cat. Therefore Pierre sleeps 18 hours a day. Which is why most of us don't use formal logic much in our daily lives, and why it is of limited value in opinion writing. In fact, many of the opinions in letters and editorials that infuriate readers the most are faulty exercises in formal logic in which the writer incorrectly assumes that a premise is commonly accepted.