How do you know? Were you there?

Interviewer (Carl Reiner): Here's a man who was actually seen at the crucifixion 2000 years ago. 2000 Year Old Man (Mel Brooks): Oh, boy. Interviewer: You knew Jesus? 2000 Year Old Man: Yeah. Thin lad, wore sandals, long hair, walked around with 11 other guys. Always came into the store, never bought anything. Always asked for water. You have not seen your own brains — do you believe you have any?

"How do you know? Were you there?" is a summary dismissal of evolution and "Old Earth" science used by some creationists, who weren't there either. This response is a form of escape hatch argument used to question and dismiss any evidence that isn't in line with young earth creationism (YEC) beliefs. The thinking behind it is that if we cannot personally verify what we've inferred from evidence (because traveling back in time is impossible, and even if it were possible, how could it be verified?) then we cannot be certain of facts and theories when it comes to describing the world as it was millions of years ago.

Although "How do you know?" is a valid question, and one that can be answered with relative ease, the aim and context of the overall question is to dismiss any particular answer to it because the "Were you there?" answer would be "no". In the usual creationist model of the world of evidence, uncertainty like this means that any answer to the origin of the Universe, even theirs, must be valid. Ken Ham has achieved some notoriety for urging credulous youths to follow up the question with a statement along the lines that "Well I know someone who was, and here is his book" — meaning, of course, the Bible. Ham is not known for preparing them to answer questions in turn about how they know the Bible contains an accurate account when it gives no sources, or why it should be considered better evidence than the Hindu Veda, which also claims to know how the world began, and its answer is at least vaguely in line with the astronomical evidence. Or, even so much as where the Bible explains things as the creationists claim. Also, one doesn't have to be there to know what happened. Just try countering the findings of a forensic scientist with were you there, and one doesn't have to be looking to know that if an apple is tossed, it will fall.

Assumptions
Creationists like to argue that evolution is "not a science" because "no one was there to observe it, and there are no experiments to run today to test it!". The inability to observe past events, or set up controlled experiments, is no obstacle to a sound science of cosmology, geology, or archaeology — so why should it be for a sound science of evolution? The key is the ability to test one's hypothesis. The presumption of "How do you know? Were you there?" seems to be that only first-hand, eyewitness testimony is reliable — and so it is illegitimate to make inferences about things beyond our immediate observations. Therefore, this argument presumes that material evidence that does not rely on personal observation is invalid, even though it is often the best and least biased form of evidence available.

When considering historical evidence, first-hand accounts (primary sources) are generally taken as better evidence than second or third-hand accounts and those written down long after the fact (secondary sources). However, this is a mere guideline and the first-hand accounts can often be subject to greater bias, as even eyewitnesses can lie, remember incorrectly, exaggerate or simply view events through their own political or social twist. This is why gathering evidence about the past is an exercise in the interplay between direct and indirect forms of evidence (particularly the material, non-personal evidence dismissed by this creationist claim), and in looking at individual pieces of evidence with a knowledgeable and critical eye. With this in mind, one can unravel the fallacies in this creationist "argument".

This assumption, that the only first-hand (primary) accounts are valid, is notably odd given our attitudes to personal accounts in other areas of life.

In a court of law, for example, eyewitness testimony is considered relatively weak evidence compared to physical evidence because people can lie, exaggerate or forget events, and contradictions can mount when multiple stories conflict. On the other hand, the more indirect or secondary evidence has not passed through such a filter of unreliability. The evidence least likely to be subject to a personal bias can then be used to spot or compensate for the biases found in personal testimony. The court of law example/analogy here is an important one because young earth creationists often raise it as the example when attempting to justify their objection to indirect evidence; the underscoring fact is that eyewitness evidence is taken to be a lie or exaggeration if it conflicts with less biased evidence.

The ins and outs of the legal system aren't the only place where we can see this "were you there?" attitude dismissed as ineffectual. It is very unlikely that one would believe extraordinary claims by word-of-mouth and an eyewitness statement alone. Carl Sagan's skeptical parable The Dragon in My Garage shows one hypothetical case where eyewitness testimony is simply unreliable, as no listener (at least no sane listener) is likely to simply accept wild claims without corroboration.

Therefore it is not valid to say that because someone was not personally present that they cannot make a very informed and very accurate appraisal of a situation given other, less biased evidence, no matter how supposedly indirect.

Contradictions
If I can't believe in an earth that's older than 6k years because "I wasn't there to see it" then I'm not going to believe in a guy coming back to life three days after being stabbed through the chest with a spear either, because "I wasn't there to see it". The obvious contradiction here is that anyone using this argument also wasn't there to see the event and wasn't there to verify whether anyone else was there. If the accusation is that no one was around to see evolution in action, the accusation that no one was around to see God magic the Universe into existence 6,000 years ago is equally true. Someone can claim that the Bible is such first-hand evidence, but unless the person using the "were you there?" argument was around when the Bible was written (unlikely) or has personally supervised every copy of it made between creation in 4,004 BCE and today, the same accusation applies.

Indeed, who could have even been the eyewitnesses during creation week? Even if you count Adam being there ( the Biblical account suggests humans appeared after creation deductive reasoning requires the beginning of the universe occurring before witnesses came to be, regardless of whether the beginning comes from creation or science or other methods. As such, apparently there weren't eyewitnesses to the putative creation in question), whatever Adam would have written would be incomprehensible after the Tower of Babel, if he even had anything written at all. If the eyewitness is purported to be God himself, an obvious objection is that God didn't personally write the Bible himself. He may have inspired or directed others to write it, but this (not to mention the many rewritings and translations made since) breaks the direct line from the eyewitness. This is without even considering the usual objections to divine inspiration for the Bible: its internal contradictions and spotty morality, etc.

The irony here is that it is valid to use the Bible as indirect evidence, providing that it is examined with a sufficiently critical eye to understand what it can say — but isn't under conditions where "How do you know? Were you there?" is a valid argument. As a flagrantly anti-intellectual dismissal of the validity of any evidence pertaining to events we don't personally observe, it can be quite amusing — since the person making this argument was certainly not alive to witness the Bible being revealed or written down, he/she has no way of knowing whether what we call the Bible is the result of actual divine inspiration, or of Satanic interference or of a succession of stoners down through the ages scribbling down whatever came to mind and rationalizing it later as revealed truth. The claim that the Bible is uniquely exempt from this problem is a textbook example of special pleading. In such usage, the argument contradicts itself, which is the point. Not so incidentally, the Bible does not make the claim that the narrative of Genesis is eyewitness testimony.

2nd Epistle of Peter, Chapter 3, Verse 4
… all things continue as they were from the beginning of the creation. We are told that the laws of nature were always the same: E=mc2, the values of the important constants, like the speed of light in a vacuum, the rates of radioactive decay, the formations of tree-rings, ice layers and varves in glaciers, the speeds of continental drift. The Bible tells us that we can rely on these telling us the truth as it was from the beginning.

Intelligent design
"Thus, just because something is 'unobservable' by our eyes at this exact moment, doesn't mean we can't find compelling evidence that it exists, or that it was present."

Example: only a few humans have laid eyes on the — because it lurks on the far side of the Moon. But humans located and named it in 1959 on the basis of photography sent from the Luna 3 probe. What provides more useful and lasting information in this case: a human "who was there", glimpsing? or an operational-science camera?

If you fancy trolling as a response
If someone were to reply to the question with "yes, I was there — prove me wrong", the same logic about first-hand accounts being the only valid form of evidence would apply. How can someone prove you wrong? They weren't there! This is a patent nonsense as an actual rebuttal and answer, but if people insist on asking fatuous questions, they probably deserve it.

Or: "Yes I was and so were you, just in a different form. Those were the days!"

Or: "I witnessed all of the Big Bang — from as soon as we had time and space to do witnessing with. (I don't recall seeing you around at that stage, though.) Then a few billion years later along comes this Moses chap with this idea for a new screenplay — thought might go for a version of the story with not so much theoretical physics, but more  and a bit of  interest and sex and even a dash of  Anyway, Moses borrowed all my selfies from back then and never gave them back. They did look a bit washed-out with all that heat and light though. It took ages to finally make it the movies.  I heard it was based on a true story, but just about every movie says that nowadays."

Dear Emma B
In June 2011, Ken Ham got all impressed and gloating over one of his brainwashed minions victims school-age followers disciples (it is nigh impossible to make that not sound creepy) supposedly asking the "were you there" question of a NASA scientist who was talking about multi-million year-old Moon rock. Ham himself was very smug over the situation, stating how atheists always went ballistic over incidents like this — although not without good reason; most atheists, freethinkers and rationalists view Ken Ham's brainwashing of young children to be outright horrifying.

PZ Myers (as Pharyngula) then wrote a lengthy open letter to Emma B, the girl in question, covering in detail exactly how the scientist did know. He sums up the main problem with the "Were you there?" component of this loaded question as follows:

The take-home message from this is simple: "How do you know?" is far more interesting than "Were you there?" Naturally, Ham lost his shit over this.

Fourth-grade science test
The question was spotted in the wild by a Reddit user in April 2013 when they heard their own kid use it in response to a question about dinosaurs. It was eventually tracked down to a "science test" given to children at the Blue Ridge Christian Academy. The final question of the quiz was "The next time someone says the Earth is billions (or millions) of years old, what can you say?" with apparently full marks given for responding "were you there" (no penalties for a lack of question mark, though).

Again, Ken Ham lost his shit over this, as the test (and presumably the use of the "were you there" line) was tracked down to Answers in Genesis.

General conclusions
No, and neither were you.

The status of this phrase as a creationist escape hatch lies in the fact that it is a self-contradicting, thought-terminating cliché. It is a mindless refrain which shouldn't be taken seriously. Much of our knowledge is about things that are too big or too little, too fast or too slow, too distant or otherwise inaccessible, to be directly observed. Indeed, the real power of science comes from our ability to know about things that are directly and indirectly observable through instruments that are much better calibrated for the intended observation than the unaided eye! This is how scientific theories work: by building up a chain of causality from what the theory predicts, to what indirect evidence it produces and then what direct evidence that indirect evidence will manifest as. This can be looking at fossils to gather evidence about what creatures lived millions of years ago, or it can be looking at what lines and squiggles will appear on a computer screen to show the existence (or at least the predictive utility) of the Higgs boson.

AIG response
The above is a valid argument against the "were you there?" question. However, Answers in Genesis does have one escape hatch argument left to avoid it.

We can count up the false arguments here. First, it offers no actual evidence; it's merely argument by assertion. Second, it still conflates actual evidence with hearsay and uncorroborated eyewitness testimony — whether it's God, Jesus or the myriad authors and translators of the Bible — this alone proves nothing. Third, it's simple special pleading that their indirect evidence (though it's more akin to a claim, a rather baseless one at that, than to actual evidence) is right but an "evolutionist's" isn't. Fourth, it's just a plain and simple cop-out akin to "my mate Dave down the pub said…".

Alternatively, we can respond by asking what they are asking (again):
 * "How do you know that the special 'Someone' possesses all these parameters attributes? Were you there to validate those attributes when the Bible was being written?"
 * "How do you know He is the one who revealed to you the contents of the book? Were you there to receive the revelations regarding the contents of the Bible when it was being written?"
 * "How do you know that what was written was faithfully transcribed, copied and translated from the original manuscript, which doesn't exist any more, in the innumerable versions that had to be created in order to reach us?" The New Testament scholar Bart Ehrman showed that a great many changes occurred once a story was committed to biblical text. We can only imagine how many mutated oral-tradition versions predated the written version.
 * "How do you know that you understand it properly?"
 * "How do you know that it wasn't all made up?"
 * "I was there and you're wrong. How do you know I wasn't; were you there?"
 * "We regularly convict criminals when forensic evidence points to their being guilty even if they were the only 'witness' to testify. If witness testimony is so important and forensics so worthless, should we release most convicted murderers?"

Other uses

 * Donald Trump, in response to historians' challenges to the fake Civil War plaque that he erected on his golf course, replied "How would they know that? Were they there?"
 * Tankies love using this argument when they have lost a debate about China-related issues.
 * Flat Earthers will frequently use this argument whenever Antarctica is mentioned.
 * The "" is a satirical take on this argument, with Germans claiming that the city of Bielefeld in North-Rhine Westphalia doesn't exist because "Have YOU ever been to Bielefeld? Do you KNOW anyone who's ever been to Bielefeld?" The joke being that Bielefeld is a very boring and uninteresting city, and as a result no one would actively go there.