Does the Andromeda Galaxy disappear after you finish reading this question?

Read the following sentence:

Does the Andromeda Galaxy disappear after you finish reading this question?

What is your answer? Some of you may say ‘yes’, many I expect will say ‘no’. Others might ask what is the ‘Andromeda Galaxy’?

Well the Andromeda Galaxy, if you didn’t know, is a galaxy fairly similar to our own Milky Way which appears in the night sky in the constellation of Andromeda (assuming it is not cloudy). It is actually quite difficult to see and most people who look straight at it don’t notice it. But if you look long enough on a clear night and you know what you are looking for, you should be able to see a diffuse cloud that is about as wide as the full moon is in the night sky. The galaxy is 2.5 million light-years away from earth and contains about a trillion stars, roughly twice the number that our own Milky Way holds.

But let’s return to the sentence.

Does the Andromeda Galaxy disappear after you finish reading this question?

My answer would be ‘yes’ which might surprise you. You may be asking, ‘how can a trillion stars disappear just like that?’ Surely even though I have finished reading the question and have stopped thinking about the ‘Andromeda Galaxy’ the whole thing doesn’t just disappears from existence. And then does it just pop back into existence when I read the sentence again, and then disappear again?

The reason I posed this conundrum was to illustrate the relationship between language in the mind and the natural world. The question given is an example of language in the mind. It doesn’t exist in the natural world. The trillion stars that appear as a diffuse cloud in the constellation Andromeda do exist in the natural world. But they are not, strictly speaking, the ‘Andromeda Galaxy’. To understand why we need to analyse the language in more detail.

Let’s look at the term ‘the Andromeda Galaxy’. You may know this as a noun phrase, referring expression or definite descriptor. However it is important to remember that the term is a piece of language that exists in the mind. It doesn’t exists in the natural world and it is not the cluster of stars we have been talking about. It can point to the cluster of stars, it can refer to the  stars but it is not actually the stars that are out there in the natural world.

The name Andromeda refers to the daughter of Cassiopeia in Greek mythology who was rescued by Perseus after having been sacrificed to the sea monster Cetus. The name bears no relation in the natural world to the cluster of stars that it points to. It is an example of an arbitrary choice of name that the English language has happened upon.

The definition of the word ‘galaxy’, according to dictionary.com is:

1. a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space.

Again this word bears no natural relation to the actual cluster of stars that we have been talking about. It is an arbitrary choice.

So we are left with a rather awkward choice of term for something that from a scientific point of view seems so large and imposing. Maybe we could choose a set of words that are more descriptive, more concrete and more technical in trying to define the object? How about it we call it ‘the cluster of a trillion stars that is 2.5 million light-years from earth in the constellation of Andromeda’. Substituting this noun phrase into the question we now get

Does the cluster of a trillion stars that is 2.5 million light-years from earth in the constellation of Andromeda disappear after you finish reading this question?

While this might seem a more technical description, and one that more accurately points to the object in the night sky (although we note it still contains the name ‘Andromeda’), there is still a problem. The noun phrase is still only an approximation to the object out there. Perhaps a better approximation that the original ‘Andromeda Galaxy’ but nevertheless is still an approximation; a metaphor. Words such as ‘cluster’, ‘stars’ and ‘constellation’ are problematic themselves.

Language as a metaphor

The problem with trying to refer to objects in the natural world using language is that language can only act as a metaphor to the object being described. It is only an approximation to what is out there. It can be very useful at times say if we want to warn someone:

Look out the Andromeda Galaxy is coming towards you!

Or if are trying to get research funding:

Could you give me some money to study the Andromeda Galaxy?

But although language is useful for human communication, we have to question whether what we are talking about is really out there in the natural world. And if it is, how can we refer to it accurately and precisely?

“Andromeda Galaxy (with h-alpha)” by Adam Evans – M31, the Andromeda Galaxy (now with h-alpha). Licensed under CC BY 2.0 via Commons – https://commons.wikimedia.org/wiki/File:Andromeda_Galaxy_(with_h-alpha).jpg#/media/File:Andromeda_Galaxy_(with_h-alpha).jpg