Some people define some things (which they truly may be or are) Impossible. 'Impossible' has a humane meaning in itself. But... If 'something' is really impossible... then why can you think that? If something is impossible... then why did the neurons in your brain have that thought? It must've been impossible for them to think of something which is not possible.

Does an universal affirmative (A) premise entail a particular affirmative (I) one? I mean "All men are mortal" entails "Some men are mortal" or not? This is somehow confusing. Since, if you think that in a relation with set theory, it is impossible for (I) not to be entailed by (A). (A) intuitively entails (I). However, when looking at the opposition of square and applying, for example, tree method to prove the entailment, it results that (A) does not entail (I).

In an answer to a question, Stephen Maitzen wrote, "if one's argument depends on controversial premises, then one ought to improve the argument by finding less controversial premises that imply one's conclusion." Am I mis-reading what he wrote? Does it come across to others as "one starts with the desired conclusion and then works backwards to develop premises that would support the desired conclusion." ? There may be evidence from recent psychological studies (e.g., Kahneman's Thinking Fast and Slow that indicate that our minds actually do work in this manner. However, I was under the impression that philosophers generally reason by starting with premises that seem reasonable, and then using logic to determine where those premises lead. His statement perhaps indicates a different path.

If I'm asked "Do you have an opinion about opinions?" I cannot say "No" because then I would be expressing an opinion about opinions. Therefore isn't it impossible not to have an opinion about opinions?

"Everything in moderation" is a common view. But then moderation should be in moderation. If so, isn't moderation not fully moderate, and thus is partly immoderate?

I want to know if the structures of logical arguments changes by logicians over time (like scientific theories might change in light of new evidence)? I also wanted to know if there might also occur changes in existing logical fallacies (other than adding more fallacies to the list) and will it ever happen that the things that are now listed among logical fallacies might become a valid way to reason (I don't think so)?

I would like to know if this can be proven I am attempting to prove G with these premises: 1. (-K and -N) > [(-P> K) and (-R> G)] 2. K> N 3. -N and B 4. -P v -R I am not sure if the premises are enough to allow the solver to prove the solution or if there should be additional premises. A response would be appreciated!

Is it possible to prove within ZF(C) that the set of all proper infinite subsets of set N has cardinality that is strictly greater than |N|?

My dictionary's definition of "definition" is an "exact description of a thing". The definition doesn't contain an exact description of a thing, it only mentions it, so it doesn't qualify as a definition. Paradox?

What's an ancestral?