Is a table levitating possible, even at a minuscule probability?

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Discussion Overview

The discussion revolves around the theoretical possibility of a table levitating, exploring concepts from classical and quantum physics. Participants examine the probabilities associated with seemingly miraculous events, questioning whether such occurrences can be considered possible, extremely unlikely, or effectively impossible under current physical laws.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants inquire about the specific conditions under which a table might levitate, questioning the size of the table and the height of levitation.
  • One participant suggests that a table could be considered to levitate if it were bouncing on a monatomic layer of air molecules for a brief moment.
  • Another participant humorously posits that if one considers the concept of "nothing ever touches," then all tables are perpetually levitating.
  • Several participants discuss the implications of statistical physics, suggesting that while the probability of a table levitating is extremely minuscule, it is not definitively zero.
  • There is a contention regarding the interpretation of probabilities, with some asserting that probabilistic quantum mechanics does not negate the effects of gravity, while others argue that the probability is vanishingly small but not zero.
  • Examples such as a coin landing heads multiple times or a gas returning to a specific state are used to illustrate the concept of improbable events, with varying opinions on their relevance to the discussion of levitating tables.
  • Some participants express uncertainty about the nature of microstates and their relationship to macro events, questioning whether all microstates are indeed possible or if some should be assigned a probability of zero.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the possibility of a table levitating. While some argue it is categorically impossible, others suggest it is theoretically possible but with an extremely low probability. The discussion remains unresolved regarding the interpretation of probabilities and the implications of statistical mechanics.

Contextual Notes

Participants highlight limitations in understanding the relationship between microstates and macro events, particularly in the context of extreme probabilities and the role of classical versus quantum mechanics.

  • #31
Just to rephrase to make sure there's no confusion, I'm not counting physical trajectories; I'm counting all the sequences of states you can “freely imagine” if you treat each instant as an independent choice.
For three discrete time-steps and 200 000 possible instantaneous states, you’re constructing (200k) ^ 3 possible sequences. But almost all of those sequences violate the dynamical laws: the state at time t1 has to be the time-evolution of the state at t0, not an arbitrary pick. The same goes for t2.

If you impose the actual equations of motion, the only surviving sequences are exactly those one-to-one trajectories that start from valid initial conditions, so the set collapses back to size 200,000
 
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  • #32
syed said:
I think you're misreading.
I think you're confused. See below.

syed said:
I'm talking about imagined trajectories.
What does that even mean? Physics doesn't work by "imagining" things.

syed said:
suppose that at any instant of time, you can describe the current state of particles in 200,000 different ways.
You can't. There's just one state. You might not know what it is, but there's just one.

What you might be groping towards (but I'm not sure--see further comments at the end of this post) is an epistemic concept of probability--the standard ignorance intepretation, where we assign probabilities to different possible states because we don't know what the actual state is. We have incomplete information, and we use that information to formulate some kind of statistical description of what we know, in order to make predictions as best we can.

In such a statistical description, if the underlying dynamics is chaotic, i.e., has sensitive dependence on initial conditions, then it is true that our ability to predict gets worse and worse as we try to predict further out in time, because of something like an exponential combinatorial explosion of possibilities. However:

syed said:
Wouldn't most of these imagined trajectories have a literal probability of 0 being realized?
Not in the statistical description I just described, with chaotic underlying dynamics. The possible trajectories are not "imagined"; they're possible as far as we know, because the initial conditions could be the right ones to produce them. So all of them have nonzero probability.

syed said:
I'm not counting physical trajectories
Then you're not doing physics. and your posts are off topic here, and you need to stop posting along these lines.

syed said:
I'm counting all the sequences of states you can “freely imagine” if you treat each instant as an independent choice.
This is not physics. We're talking about physics here, where obviously the state at each instant is not independent of the previous states; the dynamical laws relate them.

I'm going to close this thread for moderation at this point, because it seems like your OP question was based on something that has nothing to do with physics. If you think there is still an actual physics question here that hasn't been answered, PM me and we can discuss it.
 
  • #33
I think this is a poor question. It is not well defined. What counts as levitating? How far off the ground? How long? Are we allowed to use a jet pack? Ropes? EM fields?

This ranges all the way from any day every day to not in a trillion lifetimes of the universe.

So without some serious clarification we are better off counting hairs in our navel. Particularly since I get the impression that you don’t actually care about tables levitating but have some other question that you prefer to dance around.

Just consider that question carefully and then ask it directly.
 
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