Claims without evidence

It can be very difficult to prove a negative. I would say, claims asserted without evidence can be dismissed until evidence is presented.

For instance: Some people claim, despite an incredible lace of evidence, that vaccines are linked to autism. This myth keeps hanging on, and anti vaxxers will say, well prove there's no link. To try and do that would be incredibly difficult and expensive, and since there has now been study after study finding no link, it seems silly and wasteful to continue wasting resources on studying this when those resources could be going to a much more worthy scientific question.

When people are in a discussion, and one presents a proposition, unless it is one already agreed upon, the propounder carries the burden of proof to substantiate the proposition. This rule of logic has been around since Aristotle, or maybe Thales. 

I think it is obvious that unless one has evidence to believe something, there is no basis upon which to believe it. Hitchens’s razor puts it, “what may be asserted without evidence, may be dismissed without evidence.” Carl Sagan added the Sagan standard: “extraordinary claims require extraordinary evidence.”

So, when someone presents a proposition but no evidence, the proper response is not to believe it, point out the lack of evidence for the proposition, and ask the propounder to provide some evidence.

If evidence is forthcoming, then the burden of proof shifts to you. You can accept the evidence or, if you do not find the evidence convincing, it is your burden to explain why.

It actually makes perfect sense. It is an affirmation that that those making the claim have the burden of proof, and one doesn't need to have evidence to dismiss the claim.

The caveat here revolves around the concept of the burden of proof and where it lies. For example, if one claimed, without evidence, that the earth was NOT flat, this claim cannot be dismissed without evidence. The burden lies with the flat-earther because of the extreme view outside of what is understood as fact.

This statement is known as "Hitchens' razor." It comes from atheist apologist Christopher Hitchens. The actual quote is: "What can be asserted without evidence can also be dismissed without evidence." It comes from the book, God Is Not Great: How Religion Poisons Everything.

Ironically, Christopher's brother, Peter Hitchens, is a Christian apologist who wrote a book titled, The Rage Against God: How Atheism Led Me to Faith .

So I guess Peter was having none of it. Maybe they developed their arguments at family dinners?

In any case, as someone who has often been thrust into the role of "Christian apologist" by atheist trolls, I have found Hitchens' quote to be a useful and witty riposte. Yes, that's right: It works for theists, too!

Of course, Hitchens would spin in his grave if he knew how I was using/misusing his epistemological "razor."

The claim is nonsense.  There really isn't that much reliable evidence going around for this to ever intellectually work, evidence is typically hard to come by, expensive to come by and unreliable all the same.  The whole point of logic is precisely that you can make legitimate claims that are not directly proven by evidence. 

Indeed the need to logically verify the validity of evidence creates an infinite regress with you forever needing more evidence to prove your existing evidence valid.

I don’t often disagree with Bo, but every now and then. This is one of the nows. Maybe a then. He says: “For example, if one claimed, without evidence, that the earth was NOT flat, this claim cannot be dismissed without evidence. The burden lies with the flat-earther because of the extreme view outside of what is understood as fact.”

The burden does lie with the flat-earther. But not because “of the extreme view outside of what is understood as fact.” It lies with the flat-earther because the flat-earther made the proposition: the earth is flat. Being the propounder of the proposition, he bears the initial burden of proof. And that is assuming we can glean a proposition from the question asked.

No, it's how scepticism works and is perfectly consistent with a rational thought process. You're saying that claims need to be backed up with evidence, especially extraordinary ones, or there is no reason to believe that they are true. 

(You could counter by saying "absence of evidence is not evidence of absence", the problem is of course, we work probabilistically, and some claims are less probable - and so more extraordinary - because their truth would contradict established knowledge. This is a principle of the scientific method and why it works so well - because the amount of evidence required is proportionate to the severity of the claim proposed).