In recent discussions with my fellow, passionate, bloggers, it has come to my attention that there are some misunderstanding and confusion of what it means to support your claims. So, I'd like to help my fellow bloggers and readers to understand what it means when you have the burden of proof. I'll try to sum this up neatly and try not to get overly technical. I'll probably be skipping lots of other things I should mention though, so don't take this as a definitive work on the subject.
Arguments Defined
When making an argument you are making a claim about the nature of reality. All arguments have premises and conclusions, and all arguments are either strong or weak in various degrees. Arguments may cite evidence as support of its claim. Arguments are not the final say on a proposition, they are at best, an approximation as to what we think is probably true. Arguments are not truth in themselves. A stronger argument may have some predictive quality. In this way, an argument somewhat functions like a scientific theory. It is open to criticism and as new evidence is uncovered. Basically, if a claim can not be falsified, then it is not an argument but an assertion.
Also, arguments always take the positive position, that is, they are trying to substantiate what is being claimed. Negative statements are not arguments, nor are they assertions. For instance the statement: I do not believe in God. There is no position being taken and this statement is a negation. You can't prove a negative. Therefore, negative statements are free from the burden of proof.
The Burden of Proof Defined
If we apply this general principle to the positive of "our local newspaper is liberally biased" we then have to ask to petitioner on what grounds. If the petitioner states that there is empirical evidence and research to prove this, we must then ask for the research and the evidence. We must also ask the petitioner what are his terms so that we may qualify the evidence that is collected, and this in turn helps us to understand how the premises of the argument substantiates the claim. We must then examine the quality of the evidence and establish that the evidence reasonably supports the claim and is of sufficient verisimilitude. As we continue our examination, we dig and try to uncover errors in reasoning and in observation. Has the petitioner made any category errors or commit any confirmation bias when selecting his evidence? Has the petitioner addressed and suggested how his conclusion may be falsified? Did the petitioner have his study or his evidence peer reviewed or vetted? Did the petitioner misunderstand the evidence? In the same way we would scrutinize a research paper, so too do we scrutinize an argument's premises in determining the likelihood of the truth of the claim.
If a number of these things are satisfied, and the petitioner has fulfilled the obligation of quality evidence and sound error free reasoning, we can say with reasonable certainty that the argument probably is a truthful proposition.
Shifting the The Burden of Proof
However, if the petitioner does not provide quality evidence nor defines his terms and refuses to do so when asked, we can safely dismiss the claim. If the premises are weak and the evidence cited is not of equal integrity to the claim ,we can again dismiss it. We can equally dismiss the claim if the petitioner asks you to do the research for him when pressed.
For example:
Since you don't believe that invisible green leprechauns are cause of alcoholism, it is up to you to show that they do not exist.
Clearly, this is a shift in the burden of proof.
In Conclusion
In order to satiate the burden of proof, plausible arguments are as only as good as the clarity of its premises, quality of evidence, and reasoning without fallacy of composition as possible. No argument is a substitute for an objective fact, but can function within reasonable doubt or certainty as to their plausibility. It is up to the petitioner to support his claim as free of fallacy as possible and respond to challenges to the claim without errors in reasoning, or by shifting the burden of proof.