Friday, July 30, 2010

Chapter 1 - Biologist or Physicists?

Hello everyone

I have just finished reading the first chapter of Nelson. For anyone who hasn’t started reading it yet, it’s a pretty easy read. It took me an hour and a half, and may take you even less, as I don’t think I am a particularly fast reader. This textbook from what I have seen so far uses quite easy language, and assumes very little background knowledge, which means it explains things in a way that is easy to understand. I have to thank Seth for his choice of textbook for this course.

Regarding this first chapter, there wasn’t much content in it that I hadn’t seen before. In particular section 1.4 which revises units and dimensional analysis was something I presume we all know and have used since high school. But this chapter was very useful for setting up the structure and conventions that I understand will be used in this textbook. I especially appreciate 1.5.4 Track 2, as it explains the conventions used when discussing moles. I would have been quite happy to use the unit mol, but I think the convention in this textbook shouldn’t be too hard to understand. I will be interested to see how this textbook measures quantities like bond energies, which are typically measured in units of kJ/mol.

Anyway, the point of this post was not to discuss the merits of the textbook we are using. I wanted to ask everyone where they perceive themselves in the dichotomy described in section 1.3. This section compares biologists to physicists, suggesting that the former tends to focus on details of a system, whereas the latter simplifies the system and focuses on an overall model. Is this a sentiment that everyone agrees with? I tend to think it is a bit of a generalisation; there would be many physicists that focus on the finer details of a physical system, and many occasions when a biologist can simplify a phenomenon to allow it to be compared to other similar situations. But I can understand where this idea is coming from.

I would place myself towards the big picture side of the scale myself. Coming from a mathematical and physical background, I am comfortable with the idea of extracting the important details of a system, and then attempting to discover the physical relationships which model them. I hope that this does not exclude me from noticing significant finer details about specific situations. I suppose this is something I will have to watch over this semester (and the future).

Where does everyone else perceive themselves on this scale?


  1. Hard to say. Given my education and career trajectory, I'm often suprised that I haven't developed a multiple-personality disorder where I switch between physicist and biologist-like versions of myself. In the past few years, I have become more physicist-like.

  2. I'd have to say Biologist. I do tend to opt towards the finer details of things. I think it has something to do with being a perfectionist.

  3. Hmmm, overall I think I would be a biologist, as I do tend to keep thinking about all the fine details of things, sometimes failing to see "the forest", but on occasion I do find myself being like the physicist and only looking at the big picture.

    I think what the true strength of someone like a biophysicist is, is the ability to see the finer details while still focussing on the big picture. It is indeed a hard concept to achieve, and I will admit that I am always likely to stay bent towards the biologist side, but if achieved, it no doubt could create a scientist with remarkable research skills. This is not to say either that scientists in other fields wouldn't achieve this either, just that a biophysicist has the strength of both biology and physics backing them up to help achieve this.

  4. I would say biologist or more likely chemist. I don't have much of a physics background and find that the examples physicists use are not very interesting to me or are antiquated. However biologists have very interesting examples but often seem to miss the point or the most interesting thing about the systems they study.

  5. Physicists say the details don't matter.

    Chemists say some details matter.

    Biologists say the details are a matter of life and death!

  6. Physicists seek the universal and simple in any system. In contrast, biologists when confronted with the complexities of the biosphere are more likely to emphasise "frozen accidents of history" and focus on details.

    How does one synthesize these complementary approaches? First appreciate the value of each. Nelson suggests 3 steps for scientific advance:

    "a) select a simplified but real model system for study

    b) represent this system by a mathematical model with as few parameters and variables as possible.

    c) deduce from the mathematical model some nonobvious, quantitative, and experimentally testable predictions."

    He emphasises that a) and b) are inductive whereas c) is deductive.

    a) and b) require a thorough knowledge of the biology.
    Physicists need to be wary of proposing models that "lead to a large body of both theory and experiment culminating in irrelevant results."

    Nelson points out that the best models may lead "to postulating entities whose very existence wasn't obvious from the observed phenomena."

    Historical examples of this include:

    Max Delbruck's deduction of the existence of a hereditary molecule (chapter 3)

    the discovery of ions pumps and ion channels in cells (chapter 11,12)

    George Gamow's proposal to find the genetic code