[ragall]

Another way to put it is that Logic deals with cause and effect situations with a correlation of 1. It's possible to have a correlation of 99%, which would be a logical error, but still a very useful bit of practical knowledge.

In this case, I would definitely agree that people that act sloppily in one aspect of business will almost always do the same in other aspects. More generally, I'd say that most classical logical fallacies are actually useful rules of thumb.

[collingreen]

What are some good examples of classical logical fallacies that are good rules of thumb in your opinion? Maybe appeal to authority and ad hominem?

Some iconic ones stick out to me as pretty bad, especially when they are so often used to exploit or mislead.

[ragall]

I'm taking these from the Wikipedia list https://en.wikipedia.org/wiki/List_of_fallacies.

* Appeal to authority, ad hominem: the conclusion might be true, you often have to judge a person's moral character and experience too.

* Appeal to tradition, wealth, poverty: sometimes the speaker has life experiences that justify the conclusion, but can't be explained in a brief conversation.

* Ad baculum: sometimes it's wise to stop engaging with the counterpart.

* Ad populum, to emotion: sometimes the argument is not really about the truth of a proposition(the existence of a problem, and gravity thereof), but about how politically feasible it is to do something about it.

* Correlation, not causation: correlation is evidence of causation in favour of the current best explanation. What that might be, is a matter for discussion. In day-to-day life we almost always lack the time for achieving 100% certainty.

More generally, very often people don't have time discuss a matter with treatise-level precision and diligence. We almost always have to rely on a judgement of the speaker or other circumstances, see also standards of proof in legal systems. Sometimes the true core of an argument is not really expressed overtly, whether consciously or not, and you have to figure out what the discussion is really about (very useful advice in a marriage or any close relationship).