Imagine if a friend of yours suddenly somehow lost all control of their body except for their mouth. They do things, and have introspective access to why, and can talk about what they're doing, but take no part in actually deciding what to do. I would still consider them to be conscious, and intuitively think that something that is more able to talk about itself is more conscious, more so than I think that being able to decide makes something conscious.
The degree vs kind distinction still works for that. You're just proposing a slippery slope and denying the first step is downward. Keep taking your friend and chopping away capabilities (more capabilities means more possibilities means more potential for conflict) - chop away their long-term memory, short-term memory, random senses, etc.
Where do you say they begin to lose some consciousness? I'm happy to say that they lose a little bit every time, with some losses being reparable over time and the exact loss.
(And I wonder how conscious your friend would actually be. Certainly, there's a lot of potential there, but judging from float tanks and the psychological effects of isolation tanks...)
(Notes confusion)
Intuitively, I think they stop being conscious when they stop being able to talk to me about what they subjectively think about the world.
Not being able to control your body makes you a bit less conscious, but not nearly as much as removing long term memory. I don't think that the degree of conflict is as important as the degree of representation.
Confusion on "subjectively think":
I think that this is a proxy for having an experience of the world, qualia and that sort of thing.
Confusion on being "able to talk":
I can have...
One of the most important points raised by the sequences is that not all minds are like humans. In quite a few places, people have discussed minds with slight changes from human minds, which seem altogether different. However, a lot of this discussion has been related to AI, as opposed to minds created by evolution. I'm trying to think of ways that minds which evolved, and are effective enough to start a civilization, could differ from humans'.
Three Worlds Collide would seem like an excellent starting point, but isn't actually very useful. As far as I recall, the Babyeaters might have learned their baby eating habits as a result of societal pressure. The main difference in their society seemed to be the assumption that people who disagreed with you were simply mistaken: this contrasts to humans' tendency to form rival groups, and assume everyone in the rival groups is evil. The Super-Happies had self modified, and so don't provide an example of an evolved mind.
So here are my ideas so far.