Not telling is lying

TL;DR: I don't have a clear guideline for when lying is right or wrong, but I have one against ontological obfuscation.

A man meets a woman. In the following days, they meet repeatedly, grow physically closer, eventually have sex, and after a few more days have a conversation in which the man tells the woman that he has been seeing other women throughout this process. He didn't bring it up before because he was unsure of how she would react. Has the man lied?

Language draws arbitrary lines in Thingspace, so two different definitions of lying could easily place the man's behavior on different sides of the line, but the question here is whether a natural joint to carve at can be found.

There is one: the intentional stance, or rather an adjacent concept I'll call the "behavioral intentional stance". One's beliefs about the world adopt the (epistemic) intentional stance towards X when they model X as having preferences and acting based on those preferences.[1] It's obvious that a liar still adopts the intentional stance epistemically when dealing with the target of their lie: they are aware that the target disprefers being deceived, and so they conceal their deception. But something adjacent to the intentional stance can be adopted or not adopted in one's behavior.

Every decision is an optimization problem: there is a set of preferences, and acting means finding world states that optimize for those preferences. To behaviorally adopt the intentional stance towards X means including X's preference in the set being optimized over. Preference sets are often incompatible, so adopting BIS towards X often means recognizing that the naive picture of how a collaboration might look is actually unworkable. Sometimes a slightly modified, compatible collaboration plans is easily found; sometimes it isn't.[2]

Main claim: There is no middle ground between adopting and not adopting BIS. One can of course adopt it partially, i.e. adopt it towards collaborating in goal A, but not adopt it with regards to goal B. But in this case there is a meta-decision at the top about which goals call for the BIS, and that decision is made unilaterally.

I'm not saying that lying, or failing to adopt BIS, is morally wrong.[3]

I'm not saying that, in the example above, the man bears any responsibility towards the woman. In particular, I'm not saying he has any responsibility to correct her naive assumptions (for instance, in a context where his revelation comes as a complete surprise rather than a known social behavior that some people do).

I'm only saying that there is no middle point between adopting BIS and not adopting it.[4]

1. Does adopting BIS towards X mean that I should be optimizing for their preferences at all times?

No. Adopting BIS towards X only matters when you want something that involves X. If you don't want anything from X, whether or not you adopt BIS makes no practical difference.

2. Doesn't everyone hide information from other all the time?

The frequency of a social behavior in a society is a property of the society, not of the behavior itself. I agree that our society normalizes both lying and the obfuscation of the nature of lying.

3. Isn't this draconian? What would you do if anyone hid even one item of information from you?

I don't think anyone has a duty to adopt BIS toward me. Most low-stakes collaborations don't require it. When I'm interested in any kind of deeper collaboration with someone, I try a conversation as early as possible to check that we share the same understanding of what adopting BIS means.

I wouldn't treat most instances of someone failing to adopt BIS toward me as particularly informative about how much I should collaborate with them. But I would treat their inability to acknowledge that they weren't adopting BIS, or their inability to see any difference between BIS and non-BIS, as a major red flag and a sign that complex collaboration with that person is probably impossible or risky.

4. What if someone hides A from X but feels uncomfortable hiding Y? Doesn't this show some consideration toward them, even within the act of concealment?

Psychological distinctions are often arbitrary and don't automatically track ontological ones. Evidence that this case is different is needed.

5. Imagine a wife who does everything to make her husband happy and who one day has an affair. She has good reason to believe he would be devastated if he found out, so she says nothing and never cheats again. Is she adopting BIS?

In most cases, not adopting BIS looks like treating X like an object, and this is indeed not the case here. But she is clearly not treating this like two agents optimizing together to move past a mistake. So it's still clearly not-BIS; it just looks like treating X as a child in this case.

6. She was fine with it!

Sure. But whoever searches with a star-shaped cookie cutter finds only star-shaped cookies.

^I adopt it when I treat rain as an action of a god I might influence by understanding their preferences. I don't adopt it when I treat rain as a physical process with nothing "behind" it.

I adopt it when I treat rain as an action of a god I might influence by understanding their preferences. I don't adopt it when I treat rain as a physical process with nothing "behind" it.

^More on this in this insightful post by Henrik Karlsson.

More on this in this insightful post by Henrik Karlsson.

^I'm also not saying it's morally right.

I'm also not saying it's morally right.

^So any potential moral disagreements reduces to the question of whether X owes Y the adoption of BIS towards them.

So any potential moral disagreements reduces to the question of whether X owes Y the adoption of BIS towards them.