Schroedinger's Cat - Revision history

Umbire the Phantom: some copyedit

2025-06-24T12:21:46Z

some copyedit

Umbire the Phantom: /* History */ detailing

2023-10-27T06:32:42Z

‎History: detailing

Umbire the Phantom: /* Description */ note ascension

2023-09-23T08:32:11Z

‎Description: note ascension

Cathartes: /* Description */ revive, not turn undead

2022-02-13T23:32:12Z

‎Description: revive, not turn undead

Netzhack: /* Encyclopedia entry */

2021-12-17T23:25:02Z

‎Encyclopedia entry

Umbire the Phantom at 22:22, 14 July 2021

2021-07-14T22:22:48Z

TK: Edit for clarity

2021-07-14T18:36:13Z

Edit for clarity

Umbire the Phantom at 18:04, 27 February 2020

2020-02-27T18:04:24Z

Umbire the Phantom at 05:30, 28 January 2020

2020-01-28T05:30:48Z

Ardub23: Tipping the box also reveals the cat's state

2019-08-14T02:40:40Z

Tipping the box also reveals the cat's state

@@ Line 3: / Line 3: @@
 ==Description==
 {{main|Quantum mechanic|Housecat}}
-Quantum mechanics have a 5% chance of being generated with a special [[large box]].{{refsrc|src/makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player. If the 50% chance fails (or housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
+Quantum mechanics have a {{frac|20}} chance (5%) of being generated with a special [[large box]].{{refsrc|src/makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player. If the 50% chance fails (or housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
 Besides its name and unusual origin, Schroedinger's Cat is just a normal housecat; you may [[domestic animal|tame it with food]], kill it for [[experience]], or even change its name with the [[call]] command. If Schroedinger's Cat is generated as dead, you can [[revive]] it, though it will be hostile.
@@ Line 19: / Line 19: @@
 ==Messages==
-{{message|The housecat inside the box is still alive!|Schroedinger's Cat is alive - a housecat is generated in the square nearest to the large box.}}
+{{message|The housecat inside the box is still alive!|Schroedinger's Cat is alive&mdash;a housecat is generated in the square nearest to that of the the large box.}}
 {{message|You think something brushed your foot.|As above, but you cannot see the housecat.}}
-{{message|The housecat inside the box is dead!|Schroedinger's Cat is dead - a [[housecat]] corpse is in the large box.}}
+{{message|The housecat inside the box is dead!|Schroedinger's Cat is dead&mdash;a housecat corpse is generated in the large box.}}
 {{message|The large box seems empty.|You probed the large box.}}
@@ Line 32: / Line 32: @@
 ==References==
 <references />
 [[Category:Monsters]]

@@ Line 10: / Line 10: @@
 ==History==
-In [[NetHack 3.4.3]], probing will simply show the box as empty. This was [[Bugs in NetHack 3.4.3#C343-263|bug C343-263]].
+In [[NetHack 3.4.3]] and earlier versions, including some variants based on these versions, zapping the box containing Schroedinger's Cat with the wand of probing will simply show the box as empty. This is [[Bugs in NetHack 3.4.3#C343-263|bug C343-263]], and was fixed in February 2007 via {{commit|7abf238f1b544eb2ec87575a2ccabbab98bc1510|commit 7abf238}}.
 ==Origin==

@@ Line 7: / Line 7: @@
 Besides its name and unusual origin, Schroedinger's Cat is just a normal housecat; you may [[domestic animal|tame it with food]], kill it for [[experience]], or even change its name with the [[call]] command. If Schroedinger's Cat is generated as dead, you can [[revive]] it, though it will be hostile.
-The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|src/mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse; however, a [[wand of probing]] will say that the box ''seems'' empty.
+The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|src/mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse; however, a [[wand of probing]] will say that the box ''seems'' empty. [[Ascension]] with an unopened box containing Schroedinger's Cat will reveal whether or not the cat was alive or dead.
 ==History==

@@ Line 3: / Line 3: @@
 ==Description==
 {{main|Quantum mechanic|Housecat}}
-Quantum mechanics have a 5% chance of being generated with a special [[large box]].{{refsrc|makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player. If the 50% chance fails (or housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
+Quantum mechanics have a 5% chance of being generated with a special [[large box]].{{refsrc|src/makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player. If the 50% chance fails (or housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
-Besides its name and unusual origin, Schroedinger's Cat is just a normal housecat; you may [[domestic animal|tame it with food]], kill it for [[experience]], or even change its name with the [[call]] command. If Schroedinger's Cat is generated as dead, you can reanimate its corpse using [[turn undead]], though it will be hostile.
+Besides its name and unusual origin, Schroedinger's Cat is just a normal housecat; you may [[domestic animal|tame it with food]], kill it for [[experience]], or even change its name with the [[call]] command. If Schroedinger's Cat is generated as dead, you can [[revive]] it, though it will be hostile.
-The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse; however, a [[wand of probing]] will say that the box ''seems'' empty.
+The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|src/mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse; however, a [[wand of probing]] will say that the box ''seems'' empty.
 ==History==

@@ Line 26: / Line 26: @@
 ==Encyclopedia entry==
 {{encyclopedia|
-Imagine a sealed container, so perfectly constructed that no
+Imagine a sealed container, so perfectly constructed that no physical influence can pass either inwards or outwards across its walls.  Imagine that inside the container is a cat, and also a device that can be triggered by some quantum event.  If that event takes place, then the device smashes a phial containing cyanide and the cat is killed.  If the event does not take place, the cat lives on.  In Schroedinger's original version, the quantum event was the decay of a radioactive atom.  ...  To the outside observer, the cat is indeed in a linear combination of being alive and dead, and only when the container is finally opened would the cat's state vector collapse into one or the other.  On the other hand, to a (suitably protected) observer inside the container, the cat's state-vector would have collapsed much earlier, and the outside observer's linear combination has no relevance.
 |[ The Emperor's New Mind, by Roger Penrose ]
 }}

@@ Line 1: / Line 1: @@
 In ''[[NetHack]]'', '''Schroedinger's Cat''' is the name of a [[housecat]] that is generated in the possession of a [[quantum mechanic]].
@@ Line 14: / Line 13: @@
 ==Origin==
-'''[[wikipedia:Schrödinger's cat|Schrödinger's cat]]''' is a famous thought experiment in quantum mechanics involving imagining locking a cat in a box with a mechanism that has a 50% chance of killing the cat, depending upon the final state of a quantum system, for example whether an unstable nucleus has decayed within a certain time. The orthodox [[wikipedia:Copenhagen interpretation|Copenhagen interpretation]] of quantum mechanics asserts that the cat in the box is in a superposition of possible outcomes, in half of which the cat is dead, and half of which it is alive. Only when the box is opened and "observed" does the quantum wavefunction collapse, and the fate of the cat become determined. Schrödinger constructed the thought experiment in order to assert that this, and by extension the Copenhagen interpretation, was absurd; as of this writing, physicists are still divided on this matter.
+{{wikipedia|Schrödinger's cat}}
 ==Messages==
@@ Line 44: / Line 46: @@
 <references />
 [[Category:Monsters]]
-{{nethack-364}}
+{{nethack-366}}

@@ Line 1: / Line 1: @@
 {{wikipedia|Schrödinger's cat}}{{tocright}}
 {{main|Quantum mechanic|Housecat}}
-'''Schroedinger's Cat''' is the name of a housecat that is generated in the possession of a [[quantum mechanic]]. Quantum mechanics have a 5% chance of being generated with a special [[large box]].{{refsrc|makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player; if a housecat is not created (if the 50% chance fails, housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
+Quantum mechanics have a 5% chance of being generated with a special [[large box]].{{refsrc|makemon.c|680|nethack=3.6.0}} This box will contain a housecat that is either alive or dead; the state of the cat is not fixed until it is observed by opening the box. When the box is opened, there is a 50% chance the game will attempt to create a [[peaceful]] live housecat named "Schroedinger's Cat" as close as possible to the player; if a housecat is not created (if the 50% chance fails, housecats are genocided or the level has no square free for a monster), the box will contain a named housecat [[corpse]] instead.{{reffunc|pickup.c|observe_quantum_cat}}
-Except for its name and unusual origin, Schroedinger's Cat is just a normal [[housecat]]. You may [[domestic animal|tame it with food]], kill it for [[experience]], etc. You can even change its name with the [[call]] command. If Schroedinger's Cat is dead, you can reanimate its corpse using [[turn undead]] (it will be hostile).
+Except for its name and unusual origin, Schroedinger's Cat is just a normal housecat. You may [[domestic animal|tame it with food]], kill it for [[experience]], etc. You can even change its name with the [[call]] command. If Schroedinger's Cat is generated as dead, you can reanimate its corpse using [[turn undead]], though it will be hostile.
-The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse. [[wand of probing|Probing]] will say that the box ''seems'' empty.
+The state of the cat is not fixed until it is observed in any fashion, either by opening the box or by [[tip]]ping it. Before the box containing Schroedinger's Cat is opened, it is technically empty, but its weight is increased to account for the weight of the cat.{{refsrc|mkobj.c|1341|nethack=3.6.0|comment=weight of special boxes is adjusted to include cat}} In particular, neither [[telepathy]] nor [[monster detection]] will show a live cat in the box, nor will [[food detection]] show its corpse; however, [[wand of probing|probing]] will say that the box ''seems'' empty.
 ==History==
@@ Line 19: / Line 22: @@
 {{message|The housecat inside the box is dead!|Schroedinger's Cat is dead - a [[housecat]] corpse is in the large box.}}
 {{message|The large box seems empty.|You probed the large box.}}
 ==Encyclopedia entry==
 {{encyclopedia|