dnd 5e – Does the wording of Darkvision align with accepted rules?

I think that it fits the published rules appropriately, and I haven’t seen an errata entry suggesting otherwise.

There is no fundamental, explicit limitation on how far any character can see under ideal conditions. There are implicit limitations, such as one suggested by the Barbarian class’ level 6 feature Aspect of the Beast (Eagle totem variety) which allows a character to see up to one mile away as though it were no more than 100 feet away. This suggests that typical characters’ visual ability is not good enough to allow them to see so far or well.

With regard to lighting, darkness creates a heavily obscured area, and heavily obscured areas block vision entirely. It doesn’t matter how far the darkness extends because darkness blocks all vision anyhow. Nearsighted people, farsighted people, and sharpshooters all see equivalently in pitch darkness, which is to say “not at all”.

This is what Darkvision overcomes: darkness no longer creates heavily obscured areas (for the creature with that trait). Darkness never blocks your vision, because you can see without the benefit of illumination. But you are still presumably limited by your visual ability in general; 5e just doesn’t simulate that range. Most characters with Darkvision can see as far as the DM feels is appropriate. A Barbarian with Darkvision and Aspect of the Beast (Eagle totem) could presumably see things a mile away even in pitch darkness.

So as far as they can see in darkness, they have a chance to perceive things visually (albeit with Disadvantage)– it still counts as lightly obscured for them. Dim light, in turn, goes from lightly obscured to not obscured at all for them. This seems consistent, as it is the obscuring nature of dim lighting and darkness that blocks vision for most. With Darkvision every mundane darkness is effectively at least a little bit illuminated for you.

It’s always questionable to apply reality to ambiguities in D&D rules, but the real-world mechanics of vision absolutely require some light to bounce off of something and into an observer’s eye. Light from a single source eventually fades to darkness at some distance. Darkvision, by allowing sight in total mundane darkness at all, doesn’t have such a limitation. If darkness (and its accompanying heavy obscurity) doesn’t totally prevent vision within 60 feet, I don’t have a good sense of why it would (non-arbitrarily) prevent vision at 120 feet. There certainly isn’t a defined mechanism for it.

So why the distance limitation on dim lighting? I can only speculate. It could be that, because that darkness is the lack of illumination and dim lighting is a limited amount of illumination, dim lighting can only illuminate darkness to a certain distance. Darkness may continue indefinitely, but lighting from a single source cannot.

I don’t find that totally satisfying, but as far as I can tell in officially published material there is nothing that delineates ability to see from one patch of darkness to some other patch of darkness.