We can categorise ideas and statements into two types:
- Those that are falsifiable.
- Those that are not falsifiable.
A falsifiable statement is one that it is possible, in principle, to be wrong. We may not be able to prove it right, but we can prove it wrong. For example, if I say “I have a copy of the concise Oxford Dictionary” and then if I can’t produce the copy then the statement is wrong. If I can produce a copy, then the statement may still not be right as it may belong to someone else but at least this statement has the advantage that we can falsify it.
Contrast this to a statement that cannot is unfalsifiable such as “there are extra-terrestrials on earth”. A conversation with a supporter of this statement might go something like this:
- Can you show me an extra-terrestrial alien? No, they are very difficult to find because they hide from us humans.
- Have you read any evidence from a reliable source that could show me that extra-terrestrial aliens exist? No, they are difficult to find because they hide from us humans.
- Why have they not made themselves known to us? That’s because they are here to spy on us so would not make themselves known.
- If there were another life form on earth, they would look different to us and we would notice them. These extra-terrestrial aliens are an advanced life form and can alter their shape at will so they appear to be human.
- No one has identified any single extra-terrestrial alien. This is because you have not inspected every person on earth to check.
- What if we inspected the DNA of every single person on the planet and found no extra-terrestrial aliens would that convince you? No, as an advanced intelligence they would fool us.
- And so on…
Thus the statement “there are extra-terrestrials on earth” is not falsifiable. There are many unfalsifiable ideas in life about politics, religion and our social interactions.
The trouble arises if we can’t falsify a statement then we cannot reliably assess whether the statement is right or wrong. It may still be credible, but we can never be sure. To this extent, unfalsifiable ideas and statements are not ones to live by if you can avoid it. If there is a competing statement that is falsifiable then the falsifiable statement is, all other things being equal, preferred.
It is easy to conjure unfalsifiable statements, but we should treat them all with care. The lesson to learn is: If a statement is not falsifiable, then it is inherently suspect.