Victor Stenger's Cosmological Fine Tuning Counterarguments

The fact that a lot of other things are all tied in to it certainly makes it more complicated.

But as long as we’re only talking about imaginary changes in alternate universes, it’s perfectly meaningful to wonder about a place where the charge on the electron is doubled, without any other necessary changes. Maybe the other values aren’t linked there.

In reality, yes, it’s like saying, “What if the pistons in my car’s engine were two inches wider than they are” without also widening the cylinders. Absurd! But it isn’t meaningless to ask the same question and allow for the minimum necessary engineering changes.

It’s more complex, because, in physics, we don’t know the necessary changes. Maybe an increased charge on the electron isn’t possible at all, ever. But we don’t have any clear way of knowing that.

At least with cars, people go widening their cylinders all the time.

But then it’s not a ‘varying e’-scenario, it’s a ‘throw out physics’-scenario. The thing is that saying e, or c, or any of those dimensionful constants, varies, simply has no operational meaning—for instance, just as well as doubling e, you could modify c by a factor of 1/4: the observable effect would be the same, because both are a change of the fine structure constant. Likewise, you could talk about changing the vacuum permittivity, the von Klitzing constant, the Planck charge, the magnetic permeability, and so on—these are all ambiguous terms, at best. But saying that the fine structure constant varies is meaningful across all systems of units, and hence, independent of all the anthropocentric baggage dimensionful constants are saddled down with.

Again, the most natural interpretation of ‘changing e’ is that you’re changing your system of units. So if you re-scale e, then the value of the Planck charge q[sub]p[/sub] = e/√α, changes accordingly; but then, the value of α = (e/q[sub]p[/sub])[sup]2[/sup] stays the same. Only by changing the ratio of e and q[sub]p[/sub] does anything observable change. (See also wikipedia on the notion of variable speed of light cosmologies.)

It’s throwing out physics as we know it, but it isn’t “meaningless.” We can explore, in thought-experiments, whether the damage can be limited or not.

One idea thrown about is that some of our physical constants were determined when the big-bang’s fireball started to cool down.

Could they have settled out differently? When the electromagnetic and the weak forces suddenly ceased to be unified, they might have frozen with slightly different values. We don’t have any way to know, but the thought, at least, is not meaningless.

But you’re the one introducing the magic argument. They are trying to work within the concept of a universe that God built to function, and we are part of that universe. Thus the fine tuning.

See, this is what I needed to know more about. “Fine structure constant” gave me something to go look up. Now I understand better what you are saying about how to tell a meaningful difference for c - you have to compare it to other factors. That was my question about if c was subsumed in some dimensionless constant.

I was trying to think about this, and the analogy I came up with was g[sub]c[/sub]. Back when I was learning elementary physics, g[sub]c[/sub] was presented a couple different ways. I remember it being inserted as a term to the force equation:

F = m*a/g[sub]c[/sub]

And then being told g[sub]c[/sub] = 32.2 ft-lbm/lbf-sec[sup]2[/sup] for English units, but = 1 for SI.

Finally I came to realize that, no, g[sub]c[/sub] is not a term in the force equation, it’s just a unit conversion factor to account for the attempt to use pounds as both a force and a mass unit. The relationship between those two values is the acceleration, so to have pounds as both mass and force requires a scaling factor and the modification of the units as lbm (pounds mass) and lbf (pounds force). The default assumption going to be force unless specified.

So you’re saying something similar for c?

Only if we have some background against which to compare. If you just say, ‘e varies’, then either you’re making a statement about units—in which case, nothing physically changes. Or you’re really meaning to say ‘α varies’, but then, you can equally well say ‘c varies’, or ‘ε[sub]0[/sub] varies’, because there’s no way to tell which one of them, in fact, varies; so there’s no meaning to claim that the variation is due to any specific one of those dimensionful constants. Saying ‘e varies, and maybe something else changes, too’, unless it again only means ‘α varies’, has likewise no operational meaning.

Of course, because there, you’re talking about the variation in the dimensionless coupling constants that determine the strength of those forces, rather than the dimensionful unit conversion factors that simply determine the human convention by which we describe these forces.

Exactly. Think about what it would mean to have a theory with a different g[sub]c[/sub] (having been brought up with metric, I’ve never seen this, by the way, but it’s a good example, so thanks for bringing it up): it wouldn’t mean that forces have a different strength, it would merely mean that those forces are described using a different set of units. The point is that you can get rid of all dimensionful constants in physics, which is known as nondimensionalization, but you can’t get rid of (certain) dimensionless ones: these are present, and have the same numerical value, no matter how you choose to describe the physics, but dimensionful constants aren’t—they are therefore just an artefact of the description. And what could it mean to vary c if it doesn’t even occur in some versions of the theory which are nevertheless identical with respect to the physics?