Applied logic is a form of art, akin to the art of war or the art of medicine and unrelated to the fine arts. Specifically, it is the art of persuasion - how to convince others to believe your arguments on face value. Humans talk like they think, and usually write like they talk. How a conversation with this person would be can therefore be interpreted from forum activity, and it's quite easy to understand a substantial part of the psychology of others from online behavior.
(This is why I can write this without the need to source it because because I have consumed this knowledge for so long I can teach it.)
Persuasion relies on three pillars, and you can judge many people's intelligence by their application or abuse of the art.
Ethos is the art of using authority to convince. It is the ultimate goal of the two other ways of convincing, Your very character speaks to your truthfulness - it's a part of charisma, the gift of grace.
One can appeal to authority in a number of different ways, but it is generally an appeal to correctness. A quote from Einstein is an appeal to authority, but he has been proven correct in so many of the things he said that the starting point is that everything he said is true. However, he has also been proven to be a bit unspecific and outright wrong on many assumptions, but that does not detract from the starting point that his claims are true on face value - even without physical evidence yet.
A dead giveaway is how smart the people they quote are. This is measured by how many scholars have used the quotation. If the quote is mentioned in academic textbooks as truth, then it is true as we know it. Reading books and journals are interesting, but pure knowledge is usually found in textbooks. If you want to measure a person's ethos, see how well their view is reflected in today's teaching books.
Never trust a person who's credentials are weaker than yours is correct, but always trust the person who's similar credentials are newer. Less educated older people are often not trustworthy.
Pathos is the appeal to emotion. Which specific words are used and how sentences are constructed tells you a lot about the user on the other side. Examples of bad writing:
-PEOPLE WHO WRITE IN ALL CAPS ARE MENTALLY YELLING AT YOU!!!!
-Similarly, people who over utilize exclamation points are a bit over the top excited about the topic and probably don't know too much about it even if they write really long sentences!!!!
-Dumb people will often reply to knowledge contradictory to their position with disbelief: "What did you just say!?!?!"
There are varying ways of marking specific points. Examples:
-People who CAPITALIZE all their MAJOR POINTS are YELLING these out.
-People who write in all bold is beating the argument into you.
-People who write in all cursive believes everything theyr write is important and then usually just go on a long trip down some completely....
-PEOPLE who over utilize a number of WORD ENHANCERS probably have ADD
Never trust a person who does these sort of things with any other intention of ensuring that all the important words in a sentence are actually read, using cursive. Or, they are often used to promote impact, because variations of grammatical states of words can have unexpected impact.
Logos is the acceptable way of reaching a conclusion. Showing the body of physical evidence rests on the person objecting to an argument based on logos. Logos does not have to make sense or agree with your position. Theories rely on logos to function, a theory is something that hasn't been absolutely proven by science yet, but all the evidence points towards it. The probability of correctness approaches 100%, but cannot reach it, or there can be limitations to it's application such as when General Relativity breaks down.
Idiots use mythos - the stuff behind fear based conspiracy theories. The underlying assumption for all these arguments is that someone is not telling the whole truth.Typical examples:
-God wasn't completely clear in the Bible/Torah/Koran what he meant, it's open for non-literal interpretation.
-Banks are evil.
-The US/EU are imperialistic states run purely by the military-industrial complex/big-dirty-oil/big-evil-pharma (etc)
-All Muslims are terrorists.
-Anyone who criticize representatives of other cultures is racist.
Please stop using pathos and mythos, it will never convince me.
Clean Wiki articles works very well at convincing me, but the contentious issues under debate are often not written by technical experts. And a last tip, you can fish out the good articles by looking at the author's use of pathos. :)