If the complete characterisation of a system consists of knowing its dynamical laws and evolution, then how do we account for emergent properties, such as information?
If they are only weakly emergent, there is no problem. A weakly emergent property is always derivable from microphysics, because it’s just a coarse grained summary. A strongly emergent property, on the other hand , defies reductionism.
Note however, that just because these problems are hard to solve in the dynamical laws approach, it does not mean that physicists do not have use for these concepts. When I have discussed this before I was accused of claiming that the second law of thermodynamics is not part of physics. This is not what I am saying (or what David Deutsch is saying)! Indeed, I think that the claim being made is in fact the opposite. In practice, physicists do invoke concepts like information and entropy, and the second law of thermodynamics regularly and with great success. They seem to be important for understanding the world, and yet a description of a system in terms of its initial conditions and dynamical laws will not mention them at all.
Not explicitly, but why worry if they are entirely and unambiguously derivable from what is explicitly mentioned? If I tell you there is an elephant in the room, you can infer that there is a mammal in the room, a quadruped in the room, and so on.
There is a long-standing puzzle about whether computational properties can be unambiguously derived from physics, or whether they have a semantic component. As usual , it not obvious that this problem is caused by dynamism , or cured by construction.
If they are only weakly emergent, there is no problem. A weakly emergent property is always derivable from microphysics, because it’s just a coarse grained summary. A strongly emergent property, on the other hand , defies reductionism.
Not explicitly, but why worry if they are entirely and unambiguously derivable from what is explicitly mentioned? If I tell you there is an elephant in the room, you can infer that there is a mammal in the room, a quadruped in the room, and so on.
There is a long-standing puzzle about whether computational properties can be unambiguously derived from physics, or whether they have a semantic component. As usual , it not obvious that this problem is caused by dynamism , or cured by construction.