“The Burden of Proof is always on the person who asserts the truth of something.” Well, this is close to accurate, but it isn’t really that simple.
For example, I say “there are no unicorns.” Believe it or not, the burden of proof is on YOU because all you need to do is produce ONE unicorn to prove me wrong. I could scour the world and not find a unicorn but that would not prove there are none anywhere at any time. So, too bad, YOUR burden of proof.
For example, I say “unicorns DO exist.” In this case, the burden is on ME as all I need to do is produce one unicorn to prove what I asserted.
For example, I say “all animals have two eyes.” The burden is on YOU as all you need to do is produce ONE exception of an animal with more or less than two eyes to prove me wrong. Too bad, again, YOUR burden of proof.
For example, I say “God exists.” The burden is on ME as all I need to do is show God one time. You would have to scour the universe, and even then not finding him would not be adequate proof of your non-belief. This is a special case, as we would have to agree on exactly what God IS. But the burden of proof is still on the believer. This is NOT unfair, it merely illustrates an idiosyncrasy of logic.
For example, I say “God does NOT exist.” Sorry, friend the burden is on you as all it will take is one show to prove me wrong whereas I would have to, etc.
For example, I say “X is true.” You naturally ask me to source that so-called fact. I say, “it’s on the internet, find it yourself.” You should be able to see that “it is on the internet, find it yourself” is an improper shifting of the burden of … citation. Anyone who claims to have seen something on TV, or in the news, or on the internet is 100% bound to provide the source, the PRECISE source. “Find it yourself” proves the speaker to be ignorant of the rules of logic (see above) or citation or just plain irrational.
In many if not all assertions, proving one side or the other (truth or non-truth) is often IMPOSSIBLE. It is impossible to prove the NON-existence of anything (THINK about it for a moment). In all such cases, the burden of proof rests on the person whom logic allows to prove his side of the argument. Yes, the world is unfair; who has the burden of proof is not always the speaker or the one who asserts something as TRUE.
All the above can be seen to be TRUE without resorting to a book on logic; all you must do is THINK about it, one example at a time.
Now read this again!