This [No Parking] sign is self-explanatory. The sign itself explains why it was put there - to prohibit parking in that location. We wouldn't call the sign self-evident because the sign isn't a truth, idea or function.

Why wouldn't we call a No Parking sign self-evident??? Why can't this sign be a truth, idea or function?

Consider the sign like the one below. Sign lays down the law, and constitutes the truth on the subject of parking. Sign conveys in text, and illustrates, the idea of no parking. Sign has at least 3 functions — to forbid parking, convey no parking to readers, and convey towing as the penalty of parking.

A fact can be self-evident. A fact cannot be self-explanatory.

Why not self-explanatory? Consider a fact like 1 + 1 = 2.

This is self-evident, if you can behold that adding one object (e.g. finger, toe) to another sums to 2. This is self-explanatory because if you can't see this fact — then you can physically take one object, another object, and count them!

  • This is about how words are used. Different words are used in different contexts to describe different things. That's just how language works.
    – Stuart F
    Jan 15, 2023 at 11:03
  • @StuartF your comment feels too vague. how does it answer my questions?
    – user167167
    Jan 15, 2023 at 11:31
  • @user35395 The fun thing about comments is that they don't have to answer anything :)
    – Joachim
    Jan 15, 2023 at 14:23

2 Answers 2


If you put a no-parking sign over the precipice, in the water, or at any other site where it's physically impossible to park a vehicle, you may call the sign self-evident. The property on the photograph seems ordinary, why shouldn't I park there? Because the sign says so. It explains why it was mounted there (to prohibit parking), thus it's self-explanatory. Is it self-evident? No. What is special about this place? Why is authorisation required?

To call 1 + 1 = 2 self-explanatory, you would have to set the context, and settle on the definitions. What is addition? What are 1 and 2? What base system do we use? (Binarily, 1 + 1 = 0b10). Even if you did that, you would just get a mathematical statement that has to be proved.


If you understand the concepts of a (road) sign and parking, then it is self evidently a parking sign. (That is, the fact that it is a parking sign is self evident.) What it signifies may or may not be self evident or even self explanatory. For example, in this instance, what an "unauthorised vehicle" is is not explained.

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