Derivations

The guys I was substituting for showed up on crutches to teach today so that saved me at least an hour of time in my day. I met a little bit earlier with my adviser and we re-derived the EM algorithm for the umpteenth time. Once again he stressed the importance of me be able to do it from scratch and so I just forced myself to go through the derivation line by line so that I will be able to do so next time I am in his office...which will probably be tomorrow.

The basic problem is that my current issue looks very similar to a known gaussian mixture parameter estimation problem that is solved using the EM algorithm. However there are a few issues that in my mind will make the problem insolvable using the EM algorithm; because of this I haven't spent much time going through the details of the derivation and I have been trying other routes that have been dead ends. So I am now back to where I started and perhaps I will see something I didn't see before if I just work the problem out.

We talked about my interview at FPL briefly, in summary if I get the job I can graduate with my Phd in the summer, if not I can stick around for a year, publish, travel, and make my dissertation stronger and more marketable for an academic position. I feel this is very reasonable and it is actually making my job search less stressful and giving me more options. I won't know anything for a few week, and I am hoping for the best but I am not to anxious about landing a position yet...next year I will be.

I went to a talk on campus yesterday about the conflicts between science and religion; I didn't find the talk particularly stimulating intellectually but one thing he said stuck out to me. He was talking about how the early Christian scholars dealt with perceived conflicts with science: If something is interpreted to be literally true in scripture, and it conflicts with something that has been shown to be demonstrably true in science, then you must reconsider your interpretation of that scripture.

It struck me as cynical, like acknowledging something that shouldn't be acknowledged because it sounds bad; but I guess that's what we do anyways if you just replace the word science with reason. For instance take the following verses in the New Testament:

"And these sign will follow those who believe . . . In My name . . . they will take up serpents . . ."
—Mark 16:17-18

Some people literally take this to mean that true Christians should be able to handle snakes and not be hurt; however reason leads us to believe that anyone who picks up a poisonous snake will; therefore most Christian's don't interpret this scripture literally.

Anyhow the talk covered conflicts such as heliocentricity and evolution. Another interesting point the speaker made was one that I pretty hypothesized...that ironically the church actually legitimized science during the middle ages as a practical pursuit despite the many conflicts that arose between science and religion.

There is another talk in a couple of days about the origins of the universe which I think might be interesting, so if I have time I will check it out. In the mean time I will go through my EM derivation once more and prepare for my class tomorrow. Once again I have no lecture note prepared and I still don't know if I want to give them a project to work on over the weekend...let me get back to work.