Thursday, August 24, 2006

I Was Wrong: There Are 8 Planets

Last week, I posted an article titled, "There Are 12 Planets," I was almost certain that the International Astronomical Union would accept a proposed definition of ‘planet’ that would give the solar system twelve planets. The proposal came from a committee that had studied the issue for two years. I figured that whatever they came up with, the IAU would accept.

I was wrong. A group of rebel astronomers got together and drew up an alternative proposal – one that would leave us with only eight planets. They submitted this proposal in competition to the 12-planet proposal. The rebel definition said that a planet must have Nearly) cleaned out its section of space – something that could not be said to be true of Ceres, Pluto-Charon, or the new discovery 2003UB313.

Consequently, this definition gave us eight planets.

The debate over which definition to adopt was highly political. One of the arguments in favor of the definition that allowed Pluto to be a planet was an attempt to yield to the political pressure of a pro-Pluto faction. The idea that Pluto might be removed from the list of planets brought protests from grade-school children that included an extensive letter-writing campaign to “save Pluto”. Committee members weighed the possibility that demoting Pluto would mean that astronomy itself would become less popular among school children who would be made to suffer the pangs of disappointment.

These are not the types of reasons that scientists usually weigh when they consider competing options. This was not a question that astronomers could answer by designing some sort of experiment and testing its results. The definition of 'planet' was going to be whatever the IAU said it was. The IAU could not make a mistake. When the votes were counted, whatever definition passed the approval process would become the new definition of a planet – unless and until the IAU changed its mind.

When people see these features in ethics, they say that this proves that morality is subjective and that there are no “right answers” at all in the realm of morality. Everything in morality is merely a matter of opinion.

Yet, these same traits, when they are found in astronomy, do not support that same conclusion.

This, by the way, is a reductio ad absurdum to the argument that these features prove the subjectivity of morality. If they fail to prove the subjectivity of astronomy, then how can they prove that morality is subjective?

Why I Bring This Up Again

I think that this issue is extremely important. I think that one of the reasons that theists are successful at painting atheists as morally backwards is because, in this area, atheists tend to adopt moral positions that make as little sense as those that theists adopt.

I am not going to repeat the same arguments from last week. I want to add another argument to them.

Critics of Atheism

Critics of atheism say that atheism requires a totally subjective morality – one in which the Holocaust can be made 'right' by the mere fact that a group of people get together and define 'right' in a way that includes the Holocaust.

A substantial number of atheists listen to this objection and answer, “Yeah. So? What’s wrong with that? Morality is subjective. We can make the Holocaust 'right' simply by adopting a definition of 'right' that includes the Holocaust. At the same time, we can make the Holocaust wrong by adopting a definition of ‘wrong’ that includes the Holocaust. Most of us prefer to define the term ‘wrong’ in ways that include the Holocaust, just like you do. So, it is a mistake to say that we approve of the Holocaust. We do not. We have defined it as being wrong. But, we did so in a way consistent with the idea that morality is subjective."

Against this, the "moral objectivist" argues that there has to be something more to calling the Holocaust wrong than merely defining 'wrong' to include holocausts. There has to be something really wrong with it.

The Pluto Express

Now, let’s go to Pluto.

Imagine this argument:

Astronomy is subjective. We can make Pluto a planet simply by adopting a definition of 'planet' that includes Pluto. At the same time, we can make it the case that Pluto is not a planet by adopting a definition of ‘planet’ that excludes Pluto. Whether Pluto is a planet or not does not depend on any ‘objective’ fact. It depends entirely on our subjective opinion. Therefore, astronomy is subjective.”

There is clearly something wrong with this argument. Even though everything that I say about Pluto being a planet being dependent on a rather arbitrary definition of ‘planet,’ the question of whether Astronomy is subjective or objective is independent of these considerations.

Blending Objectivity and Subjectivity

Both the moral subjectivists and their critics are making the same mistake. I can demonstrate this mistake by showing what it would be like if astronomers made the same mistake.

Assume that astronomers were in disagreement over the meaning of the word ‘planet’. However, at the same time, astronomers assumed (subconsciously, without thinking) that a ‘planet’ was any large body with a 24-hour day. They can choose whatever definition they want for ‘planet.’ In their debates, whatever definition they come up with, that is the definition that ‘planet’ will have. Yet, at the same time, they will also assert that anything that ends up being called a ‘planet’ under any definition must also have a 24-hour day.

This 24-hour-day requirement just sits there in the background. Nobody ever talks about it. Nobody ever acknowledges it. Yet, whenever you hear astronomers talk, this assumption sits in the background. While they debate whether to adopt an 8-planet definition or a 12-planet definition, it is simply assumed, quietly and without discussion, that everything that becomes a planet will have a 24-hour day.

Now, the whole issue of defining a ‘planet’ will encounter all sorts of problems. Whatever definition they come up with, somebody is going to point out that the definition includes something without a 24-hour day. Somebody is going to point out that you can’t simply cause something to have a 24-hour day just by calling it a planet. Yet, the astro-subjectivists will still be correct in asserting that whether something is a planet depends entirely on what definition of ‘planet’ we adopt, and that decision is fully subjective.

Astronomy, under this set of assumptions, becomes a mess. It becomes exactly the same type of mess we discover in discussions of morality.

Here is what those who debate ethics are doing. They are correctly asserting that whether something such as the Holocaust is bad (whether Pluto is a planet) depends on our definition of bad (planet). We are free to adopt one definition where the Holocaust is bad (Pluto is a planet), but we are just as free to adopt another definition where the Holocaust is not bad (Pluto is not a planet).

Hidden in the background at a level that everybody assumes and nobody really talks about there is this requirement that whatever ends up being called ‘wrong’ must be something that there is reason for us not to do (whatever ends up being called ‘planet’ is something that has a 24-hour day).

Now, the whole issue of defining ‘wrong’ (‘planet’) encounters all sorts of problems. Whatever definition we come up with, somebody is going to point out that the definition will call some things ‘wrong’ (a ‘planet’) that we do not have any reason not to do (that does not have a 24-hour day). Somebody is going to point out that you can’t simply cause something to be a thing we have reason not to do (to be a thing with a 24-hour day) just by calling it ‘wrong’ (just by calling it ‘a planet’). Yet, the moral subjectivists (astro-subjectivists) will still be correct in asserting that whether something ‘wrong’ (is a planet) depends entirely on what definition of ‘wrong’ (‘planet’) we adopt, and that decision is fully subjective.

The way that astronomers avoid these complications, and the way that those who discuss ethics should be avoiding these problems, is that astronomers do not allow any riders in their definitions. For example, they simply do not allow any riders that would require ‘planets’ to have 24-hour days unless this is a part of their definition of ‘planet’ The definition they choose for ‘planet’ is subjective. However, the only thing that necessarily follows from the definition they choose is that which actually, literally, follows from their selected definition – and nothing more.

Answering the Subjective/Objective Debate

What those who discuss morality should be doing is, if they are going to subjectively choose definitions for ‘wrong’, they should not allow any riders. Nothing follows from a particular act being called ‘wrong’ that does not literally follow from whatever definition they choose. In particular, it does not follow that what is ‘wrong’ is something that there is a reason not to do unless this is a part of our definition of ‘wrong’ – that it is ‘those things that we have reason not to do.’

If the moralist accepts this condition – if the moralist actually limits the definition of ‘wrong’ to those things that there is reason not to do, then moralists cannot, at the same time, assert that the definition of ‘wrong’ can be whatever they want. The definition of ‘wrong’ cannot be anything that is incompatible with ‘that which there is reason not to do.’

The moralist has to pick one of these two options. He either has to limit ‘wrong’ to ‘things that there is reason not to do’ and deny that there is any freedom to arbitrarily select or change definitions. Or he can assert a freedom to arbitrarily select or change definitions, but allow that what is ‘wrong’ might be totally irrelevant to questions of what we have reason not to do.

Which ever option he picks, morality comes a little closer to astronomy – a perfectly objective field of study, using perfectly subjective definitions. And you can go from nine planets to twelve planets and end up with eight planets within the course of a week, using fully subjective decision procedures, without even slightly questioning the objectivity of the field of study that is having this debate.

1 comment:

George Jelliss said...

It seems to me that the original decision to have 12 planets was the more logical. The new condition that a planet must dominate the region it occupies is not based on a clear objective distinction. It could be interpreted to imply that the Earth is not a planet because it hasn't disposed of the Moon (which is larger than Pluto) from its region of influence.

There are a lot of other illogicalities in astronomy. For instance why do they retain the classical "constellations" rather than divide the sky up into equal regions? John Herschel once commented that they were drawn up so as to cause the maximum possible inconvenience and confusion.

Then again, if you look up "midsummer" in a dictionary it is defined as occurring on the summer solstice, but if you look up "summer" it is defined as beginning at the solstice. So summer begins on midsummer's day! The same is true of winter on the astronomical definition.

The Astronomers also stil call the spring equinox the "First point of Aries" despite the fact that it hasn't been in Aries for centuries because of precession.