Limitation of Proposition Logic

In Artificial Intelligence subject, we have to understand the different kinds of inference mechanism,their limitation and advantages too. So today i am going to write about limitation of Proposition logic and how first-order logic helps to overcome it. So it goes this way
-The problem of infinite Model
In General Proposition logic can deal with only a finite number of propositions.
eg- If there are only three dogs Tommy,Jimmy and Laika then
T:Tommy is faithful
J:Jimmy is faithful
L:Laika is faithful

All dogs  are faithful<=>  T ∩ J ∩ L

What if there are infinite number of dogs?
So,here the propostion logic fails to explain the problem of infinite model.

First-order logic
First-order logic or Predicate logic is a generalization of proposition logic that allows us to express and infer arguments in infinite model.
eg- All men are mortal.
      Some birds cannot fly.
      At least one planet has life on it.