Intrinsic Extrinsic Intensive Extensive

There is a philosophical point, one I sometimes mention, but mostly just ignore. (Most people ignore it almost all the time). Yet, I think it is important. But attempts to explain it usually result in a “does so / does not” argument with warmers (and a “Wha?” response from most folks – as it is obscure).

It doesn’t help that the same arcane point has 2 similar sounding yet different names.

One is “Intrinsic vs Extrinsic” properties. The
other is “Intensive vs Extensive” variable or property.

Sometimes I’ve
seen “Internal vs External” property, as well.
even “Interior and Exterior”.

You would think we could pick one set of words…

So what is this, and why does it matter?

http://plato.stanford.edu/entries/intrinsic-extrinsic/

has a long discussion of it, and how it presents some sticky issues to the basic philosophy of things. (Many things…As you read that link, not only will your head start to hurt but you will run into an awful lot of “may” and “could” and not a whole lot of “is” and “must”… At least, not as much as I would have liked.

The Wiki is almost useless on this point (no surprise there):

http://en.wikipedia.org/wiki/Intensive_and_extensive_properties

In the physical sciences, an intensive property (also called a bulk property, intensive quantity, or intensive variable), is a physical property of a system that does not depend on the system size or the amount of material in the system: it is scale invariant.

By contrast, an extensive property (also extensive quantity, extensive variable, or extensive parameter) of a system is directly proportional to the system size or the amount of material in the system.

For example, density is an intensive property of a substance because it does not depend on the amount of that substance; mass and volume, which are measures of the amount of the substance, are extensive properties.

Note that the ratio of two extensive properties that scale in the same way is scale-invariant, and hence an intensive property.

Oh great. Just sort of “given” as Some are green, some are square and with no idea what it means…

But “meaning” is a philosophical concept, and leads back to the first link… and in fact, even the very understanding of what is intrinsic can lead to “issues” that can be “resistant to analysis”…

Intrinsic vs. Extrinsic Properties
First published Sat Jan 5, 2002; substantive revision Tue Jul 25, 2006

I have some of my properties purely in virtue of the way I am. (My mass is an example.) I have other properties in virtue of the way I interact with the world. (My weight is an example.) The former are the intrinsic properties, the latter are the extrinsic properties. This seems to be an intuitive enough distinction to grasp, and hence the intuitive distinction has made its way into many discussions in ethics, philosophy of mind, metaphysics and even epistemology. Unfortunately, when we look more closely at the intuitive distinction, we find reason to suspect that it conflates a few related distinctions, and that each of these distinctions is somewhat resistant to analysis.

So why does all this matter? Because “temperature” is an intensive property, while “heat content” is an extensive one. We measure “temperatures” then manipulate them as though they were “heats”, when they are not. To me, it looks like the very foundation of that manipulation is up for dispute.

A simple intuitive example:

Color is an intrinsic property of an object. (We may also want to make a distinction about perception of color, as distinct from the actual color, as human eyes do not measure photons with perfection. The Wiki tries to make this of great importance, enough to disavow color as an intrinsic property, but that is an error. Copper Sulphate solid HAS a color, even if we may perceive it as different colors under different lighting or other external changes. The wavelength of photon that comes off its atomic bond length at a given temperature is fixed by nature.)

Why does this matter?
What is the meaning of an average of two intrinsic properties?

So, take Copper Sulfate, it is blue as the whole crystal. Average that color with the red of a ruby.

What is the average color?

You can not know. To know, would require more information. Enough to turn that intrinsic property into an extrinsic one. Was it a pound of copper sulfate or a gram? A ton of ruby, or a nano-gram? Was the temperature when mixed 0 C, 1000 C, 0 K?

To know what the “Average Color” means, would require information we do not have. The “average of blue and red” is a meaning-void concept.

Taste is also an intensive property. As is smell. Coconut has a flavor. So does mint. So does liver. What is the “average flavor” of mint, liver, and coconut? Meaningless…

How MUCH of each? And how do you “average a flavor” anyway? What is the average flavor of your last 3 meals?

This “issue” holds for all intensive variables or intrinsic properties when you try to average them. It is a fundamental problem.

A Back Door Waffle

So the Wiki has an example of using an intensive property to make an average. Hidden in the way they describe it is the fact that you need to bring in the other properties that make things into an extensive property. Yet that the intensive property alone is insufficient is not made clear:

Combined intensive properties

There are four properties in any thermodynamic system, two intensive ones and two extensive ones.

If a set of parameters, {ai}, are intensive properties and another set, {Aj}, are extensive properties, then the function F({ai},{Aj}) is an intensive property if for all α,

It follows, for example, that the ratio of two extensive properties is an intensive property – density (intensive) is equal to mass (extensive) divided by volume (extensive).
[…]
Let there be a system or piece of substance a of amount ma and another piece of substance b of amount mb which can be combined without interaction. [For example, lead and tin combine without interaction, but common salt dissolves in water and the properties of the resulting solution are not a simple combination of the properties of its constituents.] Let V be an intensive variable. The value of variable V corresponding to the first substance is Va, and the value of V corresponding to the second substance is Vb. If the two pieces a and b are put together, forming a piece of substance “a+b” of amount ma+b = ma+mb, then the value of their intensive variable V is:

V= (m(a)V(a)+m(b)V(b))/(m(a)+m(b)

which is a weighted mean. Further, if Va = Vb then Va + b = Va = Vb, i.e. the intensive variable is independent of the amount. Note that this property holds only as long as other variables on which the intensive variable depends stay constant.
[…]
Note that you have to measure the amounts in the same unit that was used to calculate the intensive property from the extensive property. So when you interpolate density, you have to measure the properties in volume, as density is mass per volume. The formula makes no sense when you measure the properties in mass (kg).

All of which sounds really impressive and makes it look like it is no problem to do something like (the example they give) mix two ideal gases and get the average temperature. Yet glosses over that key term weighted.

The simple fact is that the average of two temperatures is void of meaning. It must be “weighted” in some way to have meaning. We must convert it to an EXTENSIVE variable via some kind of weighting in order for there to be some valid preservation of meaning.

Yet throughout “Climate Science” this is simply ignored. It is assumed that the value of a temperature from over a snow field is the same in extrinsic characters as the temperature over a parking lot, and that the temperature inside a Stevenson Screen is the same in extrinsic characteristics as the temperature in a MMTS or ASOS structure.

Much of the work of Anthony Watts at WUWT looking into global warming and the Surface Stations project is based on the fact that those extrinsic properties are not the same. The kind of whitewash or latex paint used on a Stevenson Screen changes the temperatures measured. The presence of a Chevy Suburban next to the thermometer in Marysville (as it was in the parking lot) changes the mass and air flow around a sensor. A thermometer in Antarctica under 4 feet of snow is in a different extrinsic milieu.

Those kinds of specifics are easily understood as “errors”. But harder to understand as exemplars of a broader issue.

A fair amount of work goes into attempts to standardize all the external factors so that we can pretend that we can average temperatures. To create a kind of standardized set of extrinsics. A given height above ground. A given color of cover. A given size of enclosure. A given kind of ground surface. A given kind of ventilation hole.

Yet, in the end, there are still things we can not standardize. Humidity changes (and with it, the specific heat of the air). Rain falls, and evaporates, and with it the heat to temperature relationship (as a phase change absorbs heat but with no change of temperature). Falling temperatures hit the dew point, then condensation happens, rather than temperature change, as heat leaves the system.

There are some we could standardize, but didn’t. Now we have data of many forms. Stevenson screens have one air volume inside and one rate of heat gain / loss, or of air flow in a given wind. MMTS have another set of such properties. ASOS yet another. Change of land use over time breaks the “average” exterior albedo, transpiration, color, air flow (think trees vs asphalt).

All those extrinsic values that we like to ignore (if a “warmer”) or harp on (if a skeptic), are all “of a whole” in that they point back to this simple core fact:

We are trying to create an average of an intensive property by assuming the extensive properties are constant and equal when they are very demonstrably anything but constant and equal.

So, take a piece of ice at 0 C and a piece of lead at 100 C. What is the “average temperature”? It’s intuitively obvious that it is 50 C. Yet nothing in that system is AT 50 C and temperature is an intrinsic property. To what object is that intrinsic property of temperature assigned?

This isn’t just pedantics.

Can you even HAVE an intrinsic property if it is not embodied IN something? The very definition of intrinsic property says “NO”.

The standard way to introduce the distinction between intrinsic and extrinsic properties is by the use of a few platitudes. Stephen Yablo provides perhaps the most succinct version: “You know what an intrinsic property is: it’s a property that a thing has (or lacks) regardless of what may be going on outside of itself.” (1999: 479). David Lewis provides a more comprehensive list of platitudes.

or

A sentence or statement or proposition that ascribes intrinsic properties to something is entirely about that thing; whereas an ascription of extrinsic properties to something is not entirely about that thing, though it may well be about some larger whole which includes that thing as part. A thing has its intrinsic properties in virtue of the way that thing itself, and nothing else, is. Not so for extrinsic properties, though a thing may well have these in virtue of the way some larger whole is. The intrinsic properties of something depend only on that thing; whereas the extrinsic properties of something may depend, wholly or partly, on something else. If something has an intrinsic property, then so does any perfect duplicate of that thing; whereas duplicates situated in different surroundings will differ in their extrinsic properties. (Lewis 1983a: 111-2)

So “Where’s the THING?”

And if there is no thing, there can not be an intrinsic property of it. An ‘average of temperatures’ is not a temperature. It is a property of those numbers, but is not a property of an object. If it is not a temperature, it is fundamentally wrong to call it “degrees C”.

Take that ice and that lead. Put the lead on the ice. What is the temperature now?

You don’t know. It depends on the relative masses.

OK, make it a ton of ice and a gram of lead. The final temperature will be 0 C as some water will change phase from ice to liquid. No THING is of 50 C. The average of 0 C and 100 C was not only meaningless, it has no predictive value. No information content about heat nor temperatures in the real world.

Yet that is what we do, day in and day out, all over “Climate Science”. We average temperatures. Yes, in GIStemp they DO average temperatures. Eventually they make “anomalies” out of these averages, but that is after they have averaged them. Further, the “temperatures” they work with are the product of making an average of a minimum and a maximum temperature at one place during a given day. (Though even there, sometimes they use ‘interpolations’ of temperatures from other places to fill in missing bits or adjust values they do not like).

So, is it OK to average two temperatures from the same place in one day?

There are actually some “issues” around that… beyond just dew point, wind, humidity and shade changes.

As P. T. Geach (1969) noted, the fact that some object a is not F before an event occurs but is F after that event occurs does not mean that the event constitutes, in any deep sense, a change in a. To use a well-worn example, at the time of Socrates’s death Xanthippe became a widow; that is, she was not a widow before the event of her husband’s death, but she was a widow when it ended. Still, though that event constituted (or perhaps was constituted by) a change in Socrates, it did not in itself constitute a change in Xanthippe. Geach noted that we can distinguish between real changes, such as what occurs in Socrates when he dies, from mere changes in which predicates one satisfies, such as occurs in Xanthippe when Socrates dies. The latter he termed ‘mere Cambridge’ change. There is something of a consensus that an object undergoes real change in an event iff there is some intrinsic property they satisfied before the event but not afterwards.

David Lewis (1986a, 1988) built on this point of Geach’s to mount an attack on endurantism, the theory that objects persist by being wholly located at different times, and that there can be strict identity between an object existing at one time and one existing at another time. Lewis argues that this is inconsistent with the idea that objects undergo real change. If the very same object can be both F (at one time) and not F (at another), this means that F-ness must be a relation to a time, but this means that it is not an intrinsic property. So any property that an object can change must be extrinsic, so nothing undergoes real change. Lewis says that this argument supports the rival theory of perdurantism, which says that objects persist by having different temporal parts at different times. While this argument is controversial (see Haslanger (1989), Johnston (1987) and Lowe (1988) for some responses), it does show how considerations about intrinsicness can resonate within quite different areas of metaphysics.

So perhaps that Stevenson Screen at 8 am is not “the same” as the one at 6 pm…

2.3 Interior vs. Exterior Properties

J. Michael Dunn (1990) suggests that odd consequences of Lewis’s theory are sufficient to look for a new concept of intrinsicness. He suggests that the notion of intrinsicness is governed by platitudes like the following. “Metaphysically, an intrinsic property of an object is a property that the object has by virtue of itself, depending on no other thing. Epistemologically, an intrinsic property would be a property that one could determine by inspection of the object itself – in particular, for a physical object, one would not have to look outside its region of space-time” (1990: 178) As Dunn notes, the metaphysical definition here is the central one, the epistemological platitude is at best a heuristic. On this view, being identical to X will be intrinsic (except in cases where X has essential properties rooted outside itself), while being a duplicate of X will not be. Also, having X as a part will be intrinsic, though it is not on Lewis’s account.

So you can see that there are some sticky issues surrounding just averaging the morning and evening temperatures for a single device (even if you ignore changes of dew point and humidity)…

A bit on thermodynamics

The wiki goes on to discuss a bit of thermodynamics. Why anyone with exposure to thermodynamics would think you can average a changing number of thermometer from around the world and have it mean anything about heat gain / loss is beyond me. All I can figure is that not many folks understand thermodynamics, or they are too lazy to actually think about it.

At any rate, it is well established how to do thermo. That is NOT to just average a bunch of temperatures while ignoring specific heat, mass, mass flow, etc. I’m going to quote a chunk of the wiki just so you can see that there are a lot of other properties that need to be added to the mix to “have meaning”.

Although not true for all physical properties, there are a number of properties which have corresponding extensive and intensive analogs, many of which are thermodynamic properties. Examples of such extensive thermodynamic properties, which are dependent on the size of the thermodynamic system in question, include volume (V), internal energy (U), enthalpy (H), entropy (S), Gibbs free energy (G), Helmholtz free energy (A), and heat capacities (Cv and Cp) (in the sense of thermal mass). Note that the main symbols of these extensive thermodynamic properties shown here are capital letters. Except for volume (V), these extensive properties are dependent on the amount of material (substance) in the thermodynamic system in question.

For homogeneous substances, these extensive thermodynamic properties each have analogous intensive thermodynamic properties, which can be expressed on a per mass basis, and the corresponding intensive property symbols would be the lower case letters of the corresponding extensive property. Examples of intensive thermodynamic properties, which are independent on the size of the thermodynamic system in question and are analogous to the extensive ones mentioned above, include specific volume (v), specific internal energy (u), specific enthalpy (h), specific entropy (s), specific Gibbs free energy (g), specific Helmholtz free energy (a), and specific heat capacities (cv and cp, sometimes simply called specific heats). These intensive thermodynamic properties are effectively material properties which are valid at a point in a thermodynamic system or at a point in space at a certain time. These intensive properties are dependent on the conditions at that point such as temperature, pressure, and material composition, but are not considered dependent on the size of a thermodynamic system or on the amount of material in the system. See the table below. Specific volume is volume per mass, the reciprocal of density which equals mass per volume.

In Conclusion

Climate Science is dedicated to the notion that you can average just one, intensive, variable, that being temperature, and do thermodynamics. (Or calorimetry).

It is just absurd on the face of it, but at a much deeper philosophical level, it has no standing. No basis in a valid philosophy. It is bankrupt of meaning.

“Global Average Temperature” is an oxymoron. A global average of tempertures can be calculated, but it is not a temperature itself and says little about heat flow. Calculating it to 1/100 of a unit is empty of meaning and calling it “Degrees C” is a “polite lie”. It is a statistitcal artifact of a collection of numbers, not a temperature at all. (There is no thing for which it is the intrinsic property).

This is clearly evidenced in the real world, as well. Thermodynamics and much of modern engineering depends on the validity of this philosophical base. Chemistry and calorimetry depend on it too. You can’t just throw that out with a wave of the Assumption Wand and expect to “get things right”. Mass matters. Phase change matters. ALL those thermodynamic properties matter. Because the philosophical basis matters.

Yet the notion of “average tmperature” is so widely embraced that any attempt to ask “Where are the Emperor’s Clothes?” is met with nothing more than derision. Yet it is a fundamental and foundational flaw to think that you can average temperatures of different objects (devoid of extensive modifiers) and have it mean anything. Anything at all.

Update

Further Reading:

Easy:

http://www.chem.tamu.edu/class/majors/tutorialnotefiles/intext.htm

Approachable:

http://iamyouasheisme.wordpress.com/2009/02/08/average-global-temperature/

In more depth:

http://www.uoguelph.ca/~rmckitri/research/globaltemp/globaltemp.html

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