Jo

Mainstream society causes there to be a commonly held default expectation in many situations. For example, if someone walking up to you on the Tube says "Excuse me", you assume that they're asking to move past you. For example, if someone says "Can I help you with that?", you assume that they are not merely wondering out of curiosity, but further offering to do so if possible. For example, if someone kisses you on the lips, you assume that they mean it romantically and/or sexually. For example, if someone hands you a shinily wrapped box on your birthday while saying "Happy birthday", you assume that they will permit you to keep it as your own possession for the rest of your life. The thing about these assumptions is that they are positive statements which are imputed, presumed, filled in by society at large, even though you never say them. When I say "Please pass the salt", the other person will interpret that as including an invisible "to me".

This phenomenon is overall pretty useful. It would be practically impossible to operate in a society if we had to be certain about what someone meant, on the sole basis of only what they explicitly stated. I don't want to have to activate my contract-drafting skills every time I say "How do you turn on this blender?"

Now, the trouble is, sometimes you might feel that a given default expectation is stupid and unfair. For example, you might think it's ridiculous to just assume that just because you have a long-term committed romantic relationship with someone, then you have to ask their permission before you have sex with someone totally different who has nothing to do with them. And, well, often you'll be right. For example, the expectation that when you say "I'm not into guys" then there's an invisible "I'm into girls" is stupid and unfair. However, that doesn't always excuse taking advantage of the default expectation to deceive and mislead persons without technically lying, because it's often immoral to deceive and mislead persons even if the sole reason for their misapprehension is their own blind internalization of a moronic and unfair societal norm.

Suppose you've decided that you will not lie. You have not necessarily sworn against deceiving or misleading persons, but you've decided to adopt the Light Wizard principle of never telling a lie. Here are some handy sub-rules.

Q: Can I use sarcasm?

A: Yes, as long as you think that most likely most people in the society in question would interpret you as being sarcastic. (To be safe, be sarcastic only if you're pretty sure that the person you're talking to will interpret it as sarcasm; if you want to be footloose and fancy-free, you may be okay with them only strongly suspecting it's sarcasm.)

Q: Can I pretend to answer a question?

A: Only if it does not answer the question. Answering "Did you graduate from Oxford?" with "I was never expelled from Oxford" is fine. Answering "Did you graduate from Oxford?" with "Yes" is not excused by saying "Well, I was answering a question you asked me last week."

Q: Can I say something false if I follow it with "Just kidding"?

A: Only if you say "Just kidding" immediately thereafter.

Q: What about April Fool's Day?

A: A common exception.

Q: What if I honestly believe what I'm saying?

A: It might be false, but it's not a lie.

Q: What if I honestly believe something I'm writing, but realize before I send/submit it that it's false?

A: Probably a lie.

Q: What if I say something and immediately thereafter realize it was false?

A: Not a lie, although I suppose this does incentivize speaking without really thinking about what you're saying, so you may want to say that Nelsonian knowledge of the truth counts for lying. In any case, it's good form to issue retractions/corrections as soon as you realize.

Q: Can I lie to be polite?

A: No.

Q: Can I say "Goodbye" even if I don't intend God to be with the other person?

A: Yes. The word in English has that meaning. Same with opening a letter with "Dear".

Q: Can I say "My learned friend" even if I think him to be uneducated, or "The Honorable" even if I think he's dishonorable?

A: Yes. That phrase, in our society, isn't supposed to be true. Much like saying "You can go to h--l"  –  it doesn't mean that the guy who cut you off in traffic should actually be sentenced to damnation.

Q: Can I say "I didn't get a chance to do the assigned reading"?

A: No.

Q: Can I say "It's okay" in response to an apology even if it's not okay?

A: I know it's a common phrase, but, well, it is meaningfully and importantly untrue. Best to say "apology accepted".

Q: Can I round? Like, say "I walked ten miles today!" if it was 9.9?

A: If the person you're talking to assumes that such rounding is an ordinary part of speech, and you're rounding within that margin, probably, sure. You might want to play it safe and say "nearly ten miles", though.

Q: Can I say "I don't know" if I'm 99% sure?

A: If you're certain for practical purposes, then you know.

Q: If I say something that I fully expect the other person to disbelieve, does that mean it can't be a law?

A: No. An alibi for murder, spoken under oath, is a lie even if nobody's buying it.

Q: When I'm bargaining, can I say that my manager/spouse doesn't want it?

A: You can argue that that's just part of the game, but I don't super approve.

Q: Can I say "probably" if it's probable only from their perspective?

A: I don't think so.

Q: Can I tell ridiculous tall tales?

A: If everyone knows that you're telling tall tales you don't want or intend anyone to believe, like the real Hieronymous Karl Friedrich von Münchhausen. 

Q: What about EULAs?

A: Well, nobody in our society expects you to be truthful there, so it might be okay?

Q: Can I say things that are metaphorically true?

A: Yes, as long as you expect the other person to think you're being metaphorical.

Q: Can I use metonyms and synecdoche?

A: It's probably okay if it makes no difference to any points you're trying to communicate, or if you don't expect the other person to care; but to be safe, probably do so only if it's clear that that's what you're doing (usually the case with common ones like "the Pentagon").

Q: What about totally inconsequential lies?

A: No.