How Can Action Be Understood in Human Terms?

[Siv]

I know about this stuff. It is certainly interesting, but it does not prove anything about free will since we do not know how our free will acts. Thinking that our free will has something to do with what we are conscious about is and that is mechanical is a real stretch. Moreover the interpretation of Libet's experiment depends on the free will of the interpreter - see e.g. http://www.newscientist.com/article/dn17835-free-will-is-not-an-illusion-after-all.html" ;)

Even the link you posted does not refute Libet's claim that our "decision" is not a conscious one, we're not aware of it when it happens, but become aware of it a few seconds later.

Now I am not sure what definition of free-will you are using here, but I am yet to see one which does not involve someone being aware of the decisions being made.
Unless, as Dennett and Pinker do, you conclude that free-will is a product of our neural activity, which tricks us into believing there is a central homunculus deciding things after looking at all the information. Which is what all the evidence seems to suggest.

 

[Upisoft]

I follow some instinct when I choose to follow some instinct. I can choose otherwise.

When was the last time that you choose "otherwise" instead?

 

[arkajad]

Even the link you posted does not refute Libet's claim that our "decision" is not a conscious one, we're not aware of it when it happens, but become aware of it a few seconds later.

I didn't posted the link to "claim" anything. I posted it for fun. Just to point it out that, like in every other discipline, nothing is sure.

Now I am not sure what definition of free-will you are using here, but I am yet to see one which does not involve someone being aware of the decisions being made.

We know too little about the subject scientifically to be able to define "free will". Some people experience it, some other not at all.

Unless, as Dennett and Pinker do, you conclude that free-will is a product of our neural activity, which tricks us into believing there is a central homunculus deciding things after looking at all the information. Which is what all the evidence seems to suggest.

No, I am not concluding anything similar to what Dennett and Pinker do. And the evidence suggests certain things to certain people and other things to other people. Much like in physics.

 

[arkajad]

When was the last time that you choose "otherwise" instead?

Frankly, I am not keeping a score. But, to give an example, out of my free will, I am choosing "otherwise" - that is not to continue my participation in this particular thread, even if I have started it.

 

[inflector]

Not sure how this got off on the free will tangent. I thought the original post was interesting. Action is not an easy concept to describe or understand intuitively.

I've been trying to think of any mechanical analogs. For example, how does the dynamics of a mechanical spring system (without friction or gravity) demonstrate the relationship between force and least action?

 

[Upisoft]

Frankly, I am not keeping a score. But, to give an example, out of my free will, I am choosing "otherwise" - that is not to continue my participation in this particular thread, even if I have started it.

That's not "otherwise". That's what you are choosing. I can read.

 

[Upisoft]

Not sure how this got off on the free will tangent. I thought the original post was interesting. Action is not an easy concept to describe or understand intuitively.

I've been trying to think of any mechanical analogs. For example, how does the dynamics of a mechanical spring system (without friction or gravity) demonstrate the relationship between force and least action?

http://www.eftaylor.com/pub/energy_to_action.html" could prove interesting reading.

 

[Maui]

Even the link you posted does not refute Libet's claim that our "decision" is not a conscious one, we're not aware of it when it happens, but become aware of it a few seconds later.

That's a rather silly statement if it's meant to imply that all our conscious choices and thoughts are pre-determined.

To be able to become aware seconds later, you need to observe(that DOES involve THINKING, being aware always involves thinking). If the thinking were pre-determined, then there would be no real thinking and no awareness. You can't be aware of anything without analyzing data(thinking). The fact that you are aware, means that there is a 'you' that thinks. Being able to be aware seconds later means that consciousness is real, and if consciousness is real then thoughts are real as well(i.e. not pre-determined, at least not at all times).

The whole idea of thoughts and consciousness being an illusion and 'we' being mere passive observers is incoherent on many levels and runs into multiple insurmountable paradoxes.

Now I am not sure what definition of free-will you are using here, but I am yet to see one which does not involve someone being aware of the decisions being made.
Unless, as Dennett and Pinker do, you conclude that free-will is a product of our neural activity, which tricks us into believing there is a central homunculus deciding things after looking at all the information.

Tricks 'us'? What do you mean by that? How could you trick an observer that DOES NOT think? But has all of his thoughts pre-determined? How about making sense? Isn't that mandatory for sound philosophical discourse?

 

[Pythagorean]

That's a rather silly statement if it's meant to imply that all our conscious choices and thoughts are pre-determined.

To be able to become aware seconds later, you need to observe(that DOES involve THINKING, being aware always involves thinking). If the thinking were pre-determined, then there would be no real thinking and no awareness. You can't be aware of anything without analyzing data(thinking). The fact that you are aware, means that there is a 'you' that thinks. Being able to be aware seconds later means that consciousness is real, and if consciousness is real then thoughts are real as well(i.e. not pre-determined, at least not at all times).

The whole idea of thoughts and consciousness being an illusion and 'we' being mere passive observers is incoherent on many levels and runs into multiple insurmountable paradoxes.
Tricks 'us'? What do you mean by that? How could you trick an observer that DOES NOT think? But has all of his thoughts pre-determined? How about making sense? Isn't that mandatory for sound philosophical discourse?

Your basic argument strategy here is attacking Siv's argument based on it's logical foundations. Yet, there's nothing wrong with the logical foundations (which are founded on empiricism).

The only thing "wrong" with his statement is that it defies our intuition, but the whole point of the scientific process is that our individual intuition is misleading:

Most scientists believed in free-will (it's a very comfortable, intuitive assumption) prior to the experiments that tested this belief. The consequences of the experiments are that (at the least) our concept of free will is completely wrong.

Freewill could still exist, but not anything like it's been defined before, so it essentially doesn't exist in the way you're thinking of it. How it exists is still a mystery (IF it exists). But you realize that in light of the empirical evidence, it is "going out on a limb" to still try and prove that it exists. It implies that you "want it to exist" despite the evidence. This kind of conundrum often leads to bad science.

 

[Upisoft]

And all that proves the "least action" hypothesis. Everyone is arguing their positions and no one does any actual action to move even a little bit...

 

[arkajad]

Thanks for all your of your input!

 

[Siv]

Not wanting to digress any more from the original topic, but Maui, I wanted to respond to your accusations.
The fact that we are aware of our decision only a few seconds after we are supposed to have made the decision implies something is wrong, does it not ?!

Sentience is a very tricky concept. People are willing to swear all sorts of things, including a soul, ghost in the machine etc etc.
But knowing how fallible we humans are, what we strongly feel is hardly likely to be true just because we strongly feel it.
We should look at what the evidence suggests.

And Pythagorean, I am a she, not a he

 

[arkajad]

But knowing how fallible we humans are, what we strongly feel is hardly likely to be true just because we strongly feel it.
We should look at what the evidence suggests.

And Pythagorean, I am a she, not a he

Being so fallible as we humans are, what's the point in looking for any evidence? We can so easily misread and misinterpret it! Or, perhaps, not all of us are equally fallible? I mean if we work really hard with a devotion to the Truth, have a help from the Goddess (as it was the case with Ramanujan ;), and have no fear of meeting the unexpected.

 

[Upisoft]

Being so fallible as we humans are, what's the point in looking for any evidence? We can so easily misread and misinterpret it! Or, perhaps, not all of us are equally fallible? I mean if we work really hard with a devotion to the Truth, have a help from the Goddess (as it was the case with Ramanujan ;), and have no fear of meeting the unexpected.

Amen! (ooops, sorry. I don't know the proper response to what you've said.)

Yes, we as humans are prone to errors and mistakes. So what is the point to devote yourself to a Goddess? You can so easily misread or misinterpret Her wishes. Maybe She doesn't want your devotion and She is upset by it instead. How can you fallible man be sure?

And you thought we have free-will, but you also think that our major moving force is our fallibleness and misinterpretation of our sensory input. What does you think "free" means? Is our will really free or it is free to be twisted by our fallibleness and thus slave to it?

 

[arkajad]

So what is the point to devote yourself to a Goddess?

No point. Devote yourself to the Truth, as I wrote. Do you think it is a bad choice?

 

[Upisoft]

No point. Devote yourself to the Truth, as I wrote. Do you think it is a bad choice?

Yes it is, because there are many truths. When you devote yourself to the Truth (or your interpretation of the Truth), you stop seeing there are other truths. The main problem is that you cannot devote yourself to the Truth (if it exists), you can only devote yourself to your fallible interpretation of the Truth. And that is bad choice, for me.

 

[bayak]

Let's leave our human affairs for a while, isn't it funny that action is energy multiplied by time or momentum multiplied by displacement while at the same time we have uncertainty relations between these quantities. Can action be strictly defined and measured even when we have uncertainties as regards its components? Can action be directly measured at all? How?

If action is length of path in space-time which wound on circle but observation one can do only in space then it is not funny.

 

[Siv]

Being so fallible as we humans are, what's the point in looking for any evidence? We can so easily misread and misinterpret it! Or, perhaps, not all of us are equally fallible? I mean if we work really hard with a devotion to the Truth, have a help from the Goddess (as it was the case with Ramanujan ;), and have no fear of meeting the unexpected.

It is precisely because we are so terribly fallible that we need objective evidence.
Subjective evidence (anecdotes etc) is not good enough precisely because we are so fallible.

 

[arkajad]

Objective evidence is always followed by a subjective interpretation. Without such an interpretation there is no "evidence". The very term "evidence" implies a subjective presupposition. Thus there is no point of denying subjectivity. The important question is how to make it less vulnerable to errors. I am suggesting that this can be done by increasing, expanding and utilizing knowledge - one of the most important factors along with seeking as much objectivity as possible.

 

[arkajad]

If action is length of path in space-time which wound on circle but observation one can do only in space then it is not funny.

Action can not be a length of path in space-time. It has a wrong physical dimension.

 

[Siv]

Objective evidence is always followed by a subjective interpretation. Without such an interpretation there is no "evidence". The very term "evidence" implies a subjective presupposition. Thus there is no point of denying subjectivity. The important question is how to make it less vulnerable to errors. I am suggesting that this can be done by increasing, expanding and utilizing knowledge - one of the most important factors along with seeking as much objectivity as possible.

Well, we seek consistency, that's all.
It could all be a Matrix scenario. But this scenario has some patterns which are independently verifiable.
Far far better than subscribing to something based on anecdotes.

 

[jambaugh]

I don't think the "least action principle" is fundamental per se. In studying graduate physics I was surprised to discover that we can essentially map any physical laws into an extremum problem. Lagrange multipliers show how to incorporate constraints into the action and so you can see the Lagrangian as merely an "action principle" formulation of the dynamic constraints (dynamical laws). It is one elegant and useful formulation but I think it manifests more as "the way we find most useful to think about things" as opposed to "the way things are deep down".

That having been said, Let me try to answer the OP's question, starting with the deeply mathematical and surfacing to a layman's definition if possible. As a background my graduate work was in deformations of physical theories through the deformation of their assumed Lie group/Lie algebra structures.

Any physical activity involves the changing of physical systems. These activities when involving continuous change we can express mathematically in terms of Lie groups. Take as an example the rotation of an object and the rotation group.

Now consider Noether's theorem and the correspondence of symmetries and conserved quantities. The corresponding quantities still exist if the symmetries are broken, they are just no longer conserved. So look upon it as a deeper correspondence between group actions and measurable quantities.

In expressing the transformation of our physical description of an object we see this correspondence in the exponentiation of a Lie algebra element to yield a group element in the form:
g(\theta) = e^{\Gamma \theta}
where the Gamma is the generator of the action and corresponds to a physical observable and the theta corresponds to a dual coordinate. The product must in general be unitless but typically we have conventional units for the components whose product is action units and we divide by Plank's constant to get a unitless exponent. E.g.
\Gamma \cdot \theta =\frac{1}{\hbar}\cdot p\cdot \Delta x
Even if this exponent is unitless there is a question of scale. Is there a (somewhat) natural scale to the group action \Gamma \cdot \theta?

For simple groups the answer is yes. There is a natural metric and measure on the simple Lie groups. This is how we get for example radian measure for rotations. If we assume that all the physical groups are singular deformations of some simple group then the natural units carry into the singular case and we can assume the (typically extreme) unit constants we find are manifestations of the extreme deformation, becoming (like c) simple unit conversion factors when we recognize the proper simple group structure.

Now let us review radian units for a moment. We typically use the arclength of the unit circle but a more easily generalized unit is the corresponding sector area (times a factor of 1/2 to get agreement but that's just a choice of convention). This half-area generalizes nicely to the hyperbolic pseudo-rotations of SR boosts. We then see it manifest in the limiting case between the two where in Galilean relativity we simply translate velocities.

If one asserts that all of the non-simple transformation groups are singular limits of actual simple or semisimple underlying groups then all group transformations has a natural unit we can call action which will be the product of a generalized momentum (generator of transformation) and generalized coordinate (transformation parameter) be it:

angular momentum times angle
energy times time
momentum times distance
pseudo-angular momentum (mass moment times c) times boost parameter
et cetera

As to why we get these units, we actualize a given amount of transformation in an object, say a relative change at some future time, by exciting the object into motion, then waiting for that motion to manifest. This excitation has energy units because of the Nother correspondence. Energy is what holds constant as we "do nothing" over time thus preserving time translation symmetry for that period. We can re-parametrize by expressing energy as some form of momentum times a rate of change for the corresponding parameter. Then the time times the rate of change gives the change in parameter and you have generic momentum times dual parameter units.

Note that the "larger" the object the more "excitation" required so the more action per parametric translation.

So for the layman action is the amount of physical transformation a system goes through "measured" in such a way that it sums over components and is independent of "how quickly" we effect the change.

 

[bayak]

Action can not be a length of path in space-time. It has a wrong physical dimension.

But it has a right metaphysical dimension. In fact, S=m*s, where mass (m) has dimension [absolute length]/[absolute time] and length between two events of this mass (s) has dimension [absolute time].

 

[jambaugh]

But it has a right metaphysical dimension. In fact, S=m*s, where mass (m) has dimension [absolute length]/[absolute time] and length between two events of this mass (s) has dimension [absolute time].

If you double the mass of an object you double the action for the same transition. That is not what "space-time distance" means. "Metaphysical dimension" sounds like you're trying to change reality to fit your "facts".

 

[ThomasT]

Nice discussion, and perhaps I'll return to some of the, er, peripheral considerations -- however, wrt arkajad's OP:

A friend, humanist by profession, asked what is "power"? Well, that was easy to explain in human terms. You do a certain amount of work, you use a certain amount of calories, you can do you work slowly, during one day, or you want to do it in one hour. Then you need more power.

Right, power refers to a certain amount of work done in a certain amount of time. The more work you can do per unit of time, the more powerful you are. I would say that the word power in ordinary language means basically the same as the word force in quantitative physics.

But the next question was about "action". To say action is energy times time, or momentum times displacement does not fly. That is good in formulas, but it tells nothing to a humanist.
To say "Planck constant is the quantum of action" does not help either.

So, how to explain what is action so that it will be understood and "felt" by a humanist or engineer? How we can relate it to our daily experience and/or engineering?

What is action philosophically?

Any ideas?

Well, is this correct? Power = Force = Mass x Acceleration. Energy = Force x Distance. Action = Energy x Time.

What mechanisms in us, human beings, are directly sensitive to action? Are there any? We are sensitive to time in an obvious way, through the rythms around us and in us. We are sensitive to energy we spend. Do we have sensors for action?

Yes, we directly detect force vis inertia.

So, what is the essence of force, or inertia? My guess? It's simply the expansion of the universe. It's why, when you drop a pebble into a calm pool of water, the wavefront travels, omnidirectionally, outward from the initial disturbance. It's the fundamental 'direction' of motion, the 'arrow of time', and kinetic energy imparted via the Big Bang. It's the fundamental wave dynamic of the universe. It's how and why, over countless iterations and interactions, we are what we are. And why, because of future countless iterations and interactions, we will eventually cease to be.

Sorry if I got a bit metaphysical there.

 

[bayak]

If you double the mass of an object you double the action for the same transition. That is not what "space-time distance" means. "Metaphysical dimension" sounds like you're trying to change reality to fit your "facts".

It is because my metaphysical space-time is wound on a sphere's product S³xS¹.

 

[ThomasT]

It is because my metaphysical space-time is wound on a sphere's product S³xS¹.

From the OP:

So, how to explain what is action so that it will be understood and "felt" by a humanist or engineer? How we can relate it to our daily experience and/or engineering?

What is action philosophically?

 

[bayak]

OP also is:

Let's leave our human affairs for a while, isn't it funny that action is energy multiplied by time or momentum multiplied by displacement while at the same time we have uncertainty relations between these quantities. Can action be strictly defined and measured even when we have uncertainties as regards its components? Can action be directly measured at all? How?

 

[ConradDJ]

So for the layman action is the amount of physical transformation a system goes through "measured" in such a way that it sums over components and is independent of "how quickly" we effect the change.

Basically, the idea of action corresponds to the idea of an event. If you designate a certain related set of changes as "an event" then it makes sense to quantify "how much happened" in that event -- which is the action.

Dividing the world up into “events” is rather arbitrary, in classical physics. All happening is continuous, and there's always more going on in the vicinity that you could include as part of whatever "event" you're talking about. It usually makes more sense to divide up the world into objects and regions in space and time, or regions in phase space.

But quantum physics is based on the notion that there is a certain minimum of action that has to happen in any physical event... so instead of a world of continuous change we have a world made of tiny events. And it appears that they always occur in the form of moments of connection between two things, i.e. interactions in which a mutual “transformation” occurs.

From a philosophical standpoint, this suggests the possibility of a relational ontology based on connection-events, rather than the traditional “objects” or “substances” that last through time. The interesting thing about that is that the world we actually experience, in real time, and the world through which we communicate with each other, is evidently a world made of interaction. But our intellectual tradition has always treated “the appearances” of things to each other as something secondary, compared with their “reality” in and of themselves.

My own view is that the lack of a well-developed picture of the world of real-time interaction is the main reason why quantum physics remains conceptually so problematic. I suspect that what we have to learn from QM and Relativity will never become clear until we learn how to imagine the physical world that we actually experience, the world of “action” in the moment. At least as a complementary viewpoint to the classical space-time picture.

 

[ThomasT]

OP also is:

Ok. Thank you.