By now, we’ve all heard the term “post-truth,” which is meant to describe a situation in which the truth doesn't really matter anymore. We can identify at least six factors which explain this situation:

1. The idea of truth relativism,
2. Mistrust in traditional sources of information,
3. Junk “news,” propaganda, and misinformation,
4. No barrier to entry for publishing,
5. Google, Facebook, Twitter, etc., and
6. Backwards reasoning.

Let’s look at these factors more closely.

The idea of truth relativism

Truth relativism is roughly the idea that everyone is entitled to their “own truth,” or that everything is a matter of opinion, and this turns out to be the idea that there is no such thing as truth. But that just can't be correct. At least not for the simplistic reasons that most people would hold this view (for example, perhaps they notice that people disagree about things, and conclude that there therefore is no truth with respect to any question.)

But if Kyrie Irving says that the Earth is flat, the correct thing to say about this is not what commissioner Adam Silver did-- that he “personally thinks” that it is round, as if both views are equally good. Irving is just wrong. Perhaps what motivates truth relativism is the idea of “respect for others”-- and this is a good thing to have, especially in areas where it is difficult to figure out what is true, or whether there are even clear answers to the questions we are asking.

Notice on such questions (religious, political, etc.), I might well think that I am correct about, say my political views (well, in my case, I'm not sure I even know what those are)-- because, after all, if I didn't think the claims I accept about politics were true, why would I believe them? So, the sensible thing to say here is that, even when it comes to religion or politics, it isn't that “everyone is equally correct,” it is that it is really, really difficult (although presumably not in principle impossible) to know whom is correct, so it seems like a good principle not to go around insisting that people that disagree with my views about politics or religion, etc. are wrong.

On the other hand, suppose someone thinks “vaccines cause autism” or that “the moon landings were faked.” Now, unlike for the political, religious, ethical, etc. questions, in which we perhaps aren't even sure how to get started trying to have a discussion with someone who has different views in that we need to find some agreed upon starting points; for these claims, in these cases we can adopt clear rational procedures to settle these questions. In the first case, we consult the relevant data, and fairly interpret it; and in the second case, we look at the available evidence.

In the first case (“vaccines cause autism”) we'll find that there isn't a single piece of scientifically acceptable evidence to support this claim; and in the second case (“the moon landings were faked”) we'll also find a similar lack of evidence, and an overwhelming amount of evidence to support the claim that human beings did in fact land on the moon. (The next move defenders of such claims will generally make is to give a fallacious appeal to ignorance (“you can't prove that they don't”/ “you can't prove that they weren't”).

In fact, what is interesting is that for people who believe these things it is likely that no amount of evidence will convince them otherwise, as people who hold these sorts of opinions will ultimately fall back on their ultimate line of defense: truth relativism-- that they are entitled to believe whatever they want and call it true. But hopefully we've established by now that there isn't a theory of truth that supports this position.

Many people have a just general sense that something isn't quite right with (well, first of all society, etc.) and further and more to the point here, the information they receive.

As (again) Kyrie Irving claimed:

“All these things that they keep giving to us, all this information, I’m just saying that these things that used to put me in fear, it makes you not want to question it naturally, because of how much information you actually can figure out and how much information there actually is out there. It’s crazy. Anything that you have a particular question on, ‘Okay, is the Earth flat or round?’ I think you need to do research on it. It’s right in front of our faces. I’m telling you it’s right in front of our faces. They lie to us.” (Kyrie Irving Believes that the Earth is flat. It is not.” Washington Post 02/17/2017)

Let's return to the “vaccines cause autism” claim. Here again, the arguments for this belief usually include further beliefs such as “the drug companies are out to make money at all costs,” or “the government regulators are only looking out for the drug companies,” and the like. This means that, such people often don't trust reports from the National Institutes of Health, or the Centers for Disease Control, or even what their own doctors tell them, since they feel like something isn't quite right with the information they are given.

So, it turns out that, for example, history textbooks are written from a certain perspective, and that learning more about events that took place from other perspectives causes one to realize that they were being presented historical information from a somewhat limited perspective. It is furthermore the case that people in industry don't always tell the truth about the risks and dangers of the products they produce and about the pollution they create and so on, and certainly politicians don't always tell the truth, either.

Indeed, we may realize at some point in our life that not everything we see or hear or read is always completely accurate. People have different names for this phenomenon of “now I see the truth” or “now I get what 'they' are trying to hide from us.” (Who 'they' is varies on the theory on offer; notice Irving also has a mysterious 'they' as the subjects doing the lying. But who, exactly, are “they”?) However, what supposedly happens in this epiphanal moment? Does one supposedly become clairvoyant, able to see the truth of all things?

Take our history example- realizing that a given historical account is written from a point of view: well, this is right, but any decent historian will readily admit that. Does this mean that is suddenly pointless to attend a lecture from a historian who studies 13th Century England about the Magna Carta? And similarly, how does this apply to math, science, etc.? Are these “lies” as well? And does it follow from the fact that there are cases in which industry and politicians lie or cover up the dangers or risks facing the public (smoking, global warming, etc.) that “drug companies are out to kill us” or that public health researchers and doctors which have dedicated their lives to public health are part of some massive deception? Of course it doesn't.

Junk news, propaganda, misinformation

With respect to current news, again, people have the general sense that something is wrong. Well it turns out that in fact, something was wrong with (at least) about half of the news stories retweeted in Michigan at certain points last year:

“Computational propaganda distributes large amounts of misinformation about politics and public policy over social media platforms. The combination of automation and propaganda can significantly impact public opinion during important policy debates, elections, and political crises. We collected data on automation and junk news using major hashtags related to politics in the state of Michigan in the lead up to the 2016 US Presidential Election. ... Social media users in Michigan shared a lot of political content, but the amount of professionally researched political news and information was consistently smaller than the amount of extremist, sensationalist, conspiratorial, masked commentary, fake news and other forms of junk news. ... Not only did such junk news “outperform” real news, but the proportion of professional news content being shared hit its lowest point the day before the election” (Howard 2017).

And, further, people have the sense that even reporters for traditional newspapers are “out of touch.” In fact many people go so far as to (wrongly) think that there is “fake news” in the sense of being completely made up stories in traditional newspapers (not that this never happens such as in the extreme case of Jayson Blair, for example), or at minimum, that the reporters are biased in one way or another.

No barrier to entry for publishing.

Since, on the Internet, there is no barrier to entry for publishing (you can just register a domain name for a convincing sounding outfit like “National Report,” “World News Daily Report,” “Boston Tribune,” “Baltimore Gazette,” and so on (I got these examples from snopes.com)) and so there can be just flood of propaganda, the idea that real journalists are biased, or make things up entirely, is enhanced-- as there are “two sides to every story,” and the real journalists (who still care about the truth, rather than just writing clickbait) only present (or try anyway to present) the true side(!) it is easier to just believe that really there is no difference between the USA Today and the Detroit News, etc. on one side, and the “World News Daily Report” on the other.

Google, Facebook, Twitter

Since there is just a complete flood of “content” that Google treats more or less equally, it all looks the same-- legitimate information is presented right next to garbage. People can then go shopping for news or “information” that fits in with what they want to believe, without having to worry about whether the reports or information is accurate or not. Once someone finds what they want, Facebook and Twitter allows this misinformation to spread with each “share” or “retweet.” At this point, most people on, for example, Facebook, won't bother to check whether what their “friends” are sharing with them is true or not, or where the “information” comes from in the first place. The more the misinformation, disinformation, and propaganda is spread around, the more it looks legitimate.

Backwards reasoning

Consider the following argument:

A

If human beings are responsible for climate change, then we should make changes to our way of life or methods of production.
We shouldn't have to make changes to our way of life or methods of production.
--
Human beings are not responsible for climate change.

Notice that what makes this argument work has nothing whatever to do with whether humans are actually responsible for climate change. Instead, it is my belief in the second premise that leads to the conclusion. But this is reasoning backwards. What is going on here is that because I don't accept the consequences of a particular claim (the claim here being “human beings are responsible for climate change” and the consequence being “we should make changes to our way of life or methods of production”), I end up just rejecting the claim that leads me to the unwanted consequence. But this is obviously a flawed way to reason. So, here's another example:

B

If this news story is accurate, then politician p is a crook.
I don't want to have to accept that politician p is a crook.
--
The news story is not accurate.

Now you might notice that this argument isn't valid. And in fact, we might have something closer to the structure of the actual argument being used by someone who is engaged in backwards reasoning. Why isn't this argument valid? Well, because it is possible for those premises to be true, and the conclusion false. Now, notice, if I change things a slight bit, I will get a valid argument

B*

If this news story is accurate, then politician p is a crook.
Politician p is not a crook.
--
The news story is not accurate.

This argument works like (A) here. But it is this second premise that is the very point in contention, and it isn't reasonable to assume this, when that's the very thing being discussed. Now another thing quite interesting about this argument is that many people will either accept (B*), or they will accept

B**

If this news story is accurate, then politician p is a crook.
This news story must be accurate
--
Politician p is a crook

Depending on who politician p is! That is to say, they will whole heartedly affirm or reject the accuracy of the news story based solely on the conclusion the story draws. Given this tendency, combined with the non-stop flood of so-called “content” with very little agreement on any kind of benchmark, it is no wonder that some people have accepted that we live in a so-called “post-truth” period of time.

What we need to start thinking about, in a world where advertisements, propaganda, misinfomation and disinformation are becoming more and more cleverly disguised is: what is this person/text claiming, and what reasons are there for accepting this claim?

Truth hasn't gone anywhere. We still can define it, for example under the correspondence definition of truth (“P is true if and only if it corresponds to the way the world is”), and describe procedures by which we can verify whether given claims are true or not.

References

Howard, Phillip 2017. Abstract for Philip N. Howard, Gillian Bolsover, Bence Kollanyi, Samantha Bradshaw, Lisa-Maria Neudert. “Junk News and Bots during the U.S. Election: What Were Michigan Voters Sharing Over Twitter?” Project on Computational Propaganda Data Memo 2017.1. https://www.oii.ox.ac.uk/blog.