Is it just me, or does dark matter and energy sound a lot like phlogiston? 96% of the matter and energy missing required to explain why galaxies move in the way they do is an astoundingly large number. I realize that they’ve “detected” dark matter through a technique known as “lensing”. This technique is also used to detect black holes. In a nutshell, lensing is a technique whereby the bending of light is detected, allowing the astronomer to infer the presence of massive bodies like black holes that are bending the path of the light. The picture in the upper right hand corner of this post gives a sense of how this curvature appears. Similarly, dark matter is detected by tracking the curvature of light. In other words, we don’t encounter dark matter or energy directly but only through its effects on other things.
Fascinatingly, physicists have actually mapped the dark matter in the universe through this sort of inferential process. It is clear that something is producing these effects, but the whole question is what this something is. And dark matter and energy are indeed strange critters that are conveniently undetectable by more direct means. It passes right through the sort of matter we’re acquainted with, and as a result is not detectable by our instruments insofar as those instruments are all constructed of the sort of matter through which dark matter passes. In a decade of research with specially designed instruments laying about 2300 meters beneath the earth (in Montana) to shield it from solar particle, we have yet to detect a single instance of dark matter. In some respects, dark matter is the perfect exemplification of object-oriented ontology, especially in its Harmanian formulation. For Graham all objects are vacuum packed and withdraw from one another. Dark matter and energy are perfect examples of this thesis. We only encounter it, in my formulation, through the differences it produces in other things. Yet here we have the interesting epistemological question of why we should affirm its existence at all. It quite literally is a ghost. Perhaps the physicist readers of this blog can help me out here. Dark matter is certainly very strange stuff.
UPDATE: Over at object-oriented philosophy Graham got the impression that I was suggesting that his withdrawn objects are like phlogiston. This is my fault. I wrote this post in haste while cooking dinner and watching a documentary on dark matter, so I wasn’t as clear as I should have been. Two distinct things are going on in this post. On the one hand, I’m raising questions about whether or not something like dark matter actually exists and what reason we have for believing that it exists. To my eyes it looks a lot like an ad hoc scientific hypothesis reflective of serious problems at the heart of our physics. However, on the other hand, if dark matter does exist, and if it has the properties physicists attribute to it, then 1) it would not be equivalent to phlogiston, and 2) it would be an excellent example of Graham’s withdrawn objects. Apologies to Graham. I did not mean to give the impression that I was lampooning his withdrawn objects as phlogiston. Quite the contrary.