How do you know that something is real? Knowing something is real is always a matter of probability, of getting enough indicators of reality that you are comfortable assuming something is. Certainty always requires a leap of faith, though the size of the leap may vary.
Perhaps previous generations had it easier. It was real if you could hold it in your hand. Recently, having to order from a paper catalog (by mail!), I realized that if a business does not have an online presence, I find it difficult to believe it is real. If I cannot find a person, (via internet search) with their name and the town or state, I assume a pseudonym. This is especially true for professionals; For a doctor, we expect to see the medical practice they work at. For a lawyer, a law office. A teacher, we’ll find on the state’s list of licensed teachers (use the guest login, you don’t need an account). Someone writing as a professional, without an internet presence, is much harder to believe.
Once, we knew things were real when we saw them. Photoshop and video editing have made that more difficult. Perhaps we knew it was true if we heard it, watched the speech in which it was said. As video and voice editing software improves, those will become more difficult as well.
This combines rather poorly with the human tendency towards confirmation bias. We tend to see what we expect to see. When things meet our expectations, we don’t look closer. This is very sensible, since looking closer takes time, and why should we, when it seems true? But it does make us easier to deceive, and the deceptions have gotten much, much better.
On the internet, nobody knows you’re a dog. Of course, you don’t know who else is one either…