Epictetus discusses the aim and purpose of premises, arguments and logic, in general.
For in every area of study, we’re seeking to learn how a good and virtuous person may discover the path that he should follow in life and the way in which he should conduct himself.
Therefore, logic and assent seek to help the Stoic prokopton to see things as they really are.
For what is required in reasoning? To establish the truth, reject what is false, and suspend judgement in doubtful cases. ... it is necessary too to know how to test them and distinguish the true from the false and the uncertain ... accept what follows from the premisses that have rightly been granted by you. ... learn how one thing follows as a consequence from certain other things, and how one thing is sometimes derived from a single thing, and sometimes from several in conjunction. ... conduct oneself intelligently in argument, and be able to prove each of one’s points, and to follow other people’s demonstrations, without being misled by those who put forward sophistic arguments by way of proof.
In today's vernacular, we would call this critical thinking. Just as in Socrates' day, today there are sophists who would try to convince us to live a certain way based on unsound reasoning. Therefore, we need to figure out a way to cut through the malarky and try to comprehend the world as it really is and not how someone intends us to see it.
If we don't or can't take care to manage our impressions and thinking, we may fall into faulty logic. We should not
deal with our impressions in a random, ill-considered, and haphazard fashion, [or] be unable to follow an argument or demonstration or sophism, and, in a word, to be unable to make out, in question and answer, what is consistent with one’s position and what is not