Timeline for Can there be information without a "knower"?
Current License: CC BY-SA 3.0
6 events
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| Jan 19, 2017 at 11:22 | comment | added | alanf | The von Neumann entropy of the whole universe doesn't change. The von Neumman entropy of subsystems increases over time. The vN entropy of a single qubit does increase if it starts in a sharp state and becomes entangled under unitary evolution with another system. The entropy of the whole universe isn't relevant to the explanation of the possibility or lack thereof of decreasing entropy in any real experiment or interaction AFAIK. So I don't think there is a problem here. | |
| Jan 19, 2017 at 0:17 | comment | added | Alexander S King | (I haven't played with quantum computing in ten years, thanks for dragging me back into it :-) ) -- Now that I think of it, the entangled state you used as an example is a little misleading because entangled states are when Von Neuman entorpy behaves differently from "normal" Gibbs entropy - Von Neuman entropy doesn't change in unitary evolution, whether for the whole universe or one qubit - so how is it related to the second law? | |
| Jan 18, 2017 at 20:30 | comment | added | alanf | So drawing the line between exists and what doesn't exist is ambiguous if it is done according to any criterion other than whether the supposedly existing thing features in an unrefuted explanation. See "The Fabric of Reality" by David Deutsch chapter 4 for more on this topic. | |
| Jan 18, 2017 at 20:28 | comment | added | alanf | The information in the book still exists even if it can't be measured: this is an implication of the laws of physics. Positivists and empiricists might say the information doesn't exist, but their positions are false and ambiguous. Measurements are interpreted in the light of explanations and getting them right requires effort and criticism, so measurements aren't primitives. Interpreting any measurement requires explanations, so anywhere you draw the line will exclude some current explanations. Nobody has a thermometer in the sun's core but we still know the temperature there. | |
| Jan 18, 2017 at 17:41 | comment | added | Alexander S King | I get the gist of your last section on adaptability and Popper's theory of objective knowledge. I don't entirely understand your first part: How does it resolve the issue of where the information contained in a book goes after the book is burned? | |
| Jan 18, 2017 at 10:02 | history | answered | alanf | CC BY-SA 3.0 |