As a tentative rephrasing, something that's "emotionally implausible" is something that "I would never do" or that "could never happen to me." Like you, I can visualize myself falling with a high degree of accuracy; but I can't imagine throwing myself off the bridge in the first place. Suicide? I would never do that.

It occurs to me that "can't imagine" implies a binary division when ability to imagine is more of a continuum: the quality of imagination drops steadily between trying to imagine brushing my teeth (everyday), calling 911 (very rare, but I've done it before), punching through a wall (never done it, but maybe if I was mad enough), and jumping off a bridge (I would never do that).

For all four, I can imagine the physical events as bare facts; but for the first two I can easily place myself in the simulation, complete with cognitive and emotional states. That's much harder in the third case; in the fourth, I'm about as confident in my imagination as I am in trying to imagine a world where 1+1=3.

If you've exercised before, you can probably remember the feeling in your body when you're finished--the 'afterglow' of muscle fatigue, endorphins, and heightened metabolism--and you can visualize that. If you haven't, or can't remember, you can imagine feelings in your mind like confidence and self-satisfaction that you'll have at the end of the exercise.

As for studying, the goal isn't to study, per se; it's to do well on the test. Visualizing the emotional rewards of success on the test itself can motivate you to study, as well as get enough sleep the night before, eat appropriately the day of, take performance enhancing drugs, etc.

Imagination is a funny thing. You can imagine things that could physically never happen--but if you try to imagine something that's emotionally implausible to you, you'll likely fail. Just now I imagined moving objects with my mind, with no trouble at all; then I tried to imagine smacking my mother in the face and failed utterly. If you actually try to imagine having something--not just think about trying--and fail, it's probably because deep down you don't believe you could ever have it.

The human experience of colour is not really about recognizing a specific wavelength of light.

True, but irrelevant to the subject at hand.

the qualia of colour are associated more with the invariant surface properties of objects than they are with invariant wavelengths of light.

No, the qualia of color have nothing to do with the observed object. This is the pons asinorum of qualia. The experience of color is a product of the invariant surface properties of objects; the qualia of color is a product of the relationship between that experience and other similar experiences.

A human looking at an optical illusion might say, "That looks red, but it's really white," acknowledging that spectral color is objective, but psychophysical color is more malleable. But compare that sentence to "that sounds good, but it's really bad." Statements about color aren't entirely subjective--to some extent they're about fact, not opinion.

Statements about qualia are about the subjective aspect of an experience: e.g., red is the color of rage; of love; the color that means 'stop.'

Your eyes do detect the frequency of light, your nose does detect the chemical composition of smells, and your tongue does detect the chemical composition of food. That's exactly what the senses of sight, smell, and taste do.

Our brains then interpret the data from our eyes, noses, and tongues as color, scent, and flavor. It's possible to 'decode', e.g., color into a number (the frequency of light), and vice versa; you can find charts on the internet that match frequency/wavelength numbers to color. Decoding taste and scent data into the molecules that produce them is more difficult, but people find ways to do it--that's how artificial flavorings are made.

There are lots of different ways to encode data, and some of them are more useful in some situations, but none of them are strictly privileged. A non-human brain could experience the 'color' of light as a number that just happens to correspond to its frequency in oscillations/second, but that wouldn't prevent it from having qualia, any more than encoding numbers into hexadecimal prevents you from doing addition.

So it's not the 'redness' of light that's a quale; 'red' is just a code word for 'wavelength 635-700 nanometers.' The qualia of redness are the associations, connections, emotional responses that your brain attaches to the plain sensory experience.

When a human brain makes a decision, certain computations take place within it and produce the result. Those computations can be perfectly simulated by a sufficiently-more-powerful brain, e.g. Omega. Once Omega has perfectly simulated you for the relevant time, he can make perfect predictions concerning you.

Perfectly simulating any computation requires at least as many resources as the computation itself (1), so AFAICT it's impossible for anything, even Omega, to simulate itself perfectly. So a general "perfect predictor" may be impossible. But in this scenario, Omega doesn't have to be a general perfect predictor; it only has to be a perfect predictor of you.

From Omega's perspective, after running the simulation, your actions are determined. But you don't have access to Omega's simulation, nor could you understand it even if you did. There's no way for you to know what the results of the computations in your brain will be, without actually running them.

If I recall the Sequences correctly, something like the previous sentence would be a fair definition of Eliezer's concept of free will.

(1) ETA: On second thought this need not be the case. For example, f(x) = ( (x *10) / 10 ) +1 is accurately modeled by f(x) = x+1. Presumably Omega is a "well-formed" mind without any such rent-shirking spandrels.

Newcomb's problem is applicable to the general class of game-type problems where the other players try to guess your actions. As far as I can tell, the only reason to introduce Omega is to avoid having to deal with messy, complicated probability estimates from the other players.

Unfortunately, in a forum where the idea that Omega could actually exist is widely accepted, people get caught up in trying to predict Omega's actions instead of focusing on the problem of decision-making under prediction.

IAWY and this also applies to hypotheticals testing non-mathematical models. For instance, there isn't much isomorphism between Newcomblike problems involving perfectly honest game players who can predict your every move, and any gamelike interaction you're ever likely to have.

Thanks for the heads-up. Fixed.