Dear Erik,
thanks a lot for your detailed answer (and sorry for my late reply).
Actually I had seen your paper (Hoel et al. 2013) but as you discuss effective information which
I believe had been introduced in the context of IIT I was under the wrong impression the Hoel et
al. 2013 was dealing with IIT as well.
The paper was pointed out to me by a jesuit monk and philosopher whom I met a few months ago on a gathering of scientists and theologians. He claimed the paper would show that IIT features "strong emergence" which I was very sceptical about. After reading your FQXi paper I now understand that what you call "underfitting" would correspond to "strong emergence" (which as you say would be possible only from a local perspective) while overfitting would correspond to weak emergence.
Would you agree with this interpretation?
>Took me a second to find what you're talking about (which is the arrow on the second to bottom
>step in the ladder in Figure 1). Yes, the picture is infinitely more complicated than shown! I
>certainly can't draw out all the supervenient arrows also because scientists don't spend a lot of
>time looking for what Ernest Nagel called "bridge laws." In retrospect I could have just put
>"elementary particles in the standard model" which covers more bases.
Yes, "elementary particles" would be more correct, since the quark configuration is absolutely
identical in different molecular structures (such as 2 CO O_2 versus 2 CO_2) while the
electron configuration is responsible for the rather different properties (poisoneous versus harmless).
>You can have plenty of averages, or let the law of large numbers work, without causal >emergence.
>For example, rolling a die over and over won't give you any causal emergence. However, >regularly
>in science experimenters treat higher scales as causally-manipulatable variables. This can be
>reflective of causal emergence. For instance, assessing the causal relationship between two
>neurons (not their underling elementary particles). Causal emergence explains why that's not >just
>about using a simpler representation. You're possibly gaining something in this scenario: extra
>information about the causal structure that's not available at the microscale, because at the
>scale of neurons there is error-correction, whereas at the scale of elementary particle physics
>there is no error-correction. If you believe the hypothesis I lay out of the ladder of science
>being reflective of each step causally emerging from the one below it, causal emergence should >be
>incredibly common, especially in the special sciences (like biology).
I agree with your dice example (no causal emergence). What I meant was to use the averaging out
of statistical fluctuations on the micro scale to establish an idealization: such as assuming
a soccer ball to be actually a sphere in order to calculate its behavior.
Would you agree that this is causal emergence?
>As for quantum physics being less determined than classic physics - well, that's a good scale to
>look for causal emergence at.
As we have argued in our contribution, time itself may be emergent in quantum gravity. As there is no causality without time I was wondering whether in this case one could actually say that any kind of causality would be emergent. Would you agree?
"One may argue that pure information-based conecpts such as the "bill of rights" or the "contents of the bible" are totally substrate independent, and that agents exist somehow in between such imaterial objects and material physics. Would you agree with this interpretation?"
>It's a nice idea but I wouldn't agree. First, I don't think anything is actually fully
>substrate-independent, more like things are substrate-constrained to greater or less extents. >Second, I
>don't think there's some immaterial world that anything is closer to.
I agree with you that probably nothing is totally substrate independent and that there is a continuum of how strongly concepts are substrate dependent or independent. If the bill of rights would be encoded in neutrinos it probably wouldn't have many consequences. But I still would say information is immaterial. So the bill of rights is more substrate independent and defined by its information content than e.g. a brick. This is what I meant with "closer to the immaterial world". Now since both emergent causality and substrate independence seem to be related to idealization I still believe there is some connection: When you idealize you abstract from the substrate and rely on information content regarding to these idealized macroscopic properties. Since this information is not directly linked the properties of constituents it is more substrate independent and thus can be realized in various concepts: the information aspect dominates the matter aspect. At the same time this description allows for more causal emergence.
Once more thanks for your essay. Even if I don't understand all details yet and may not agree with
everything it is in some respects a eye opener.
Heinrich