Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The why questions in biology

  1. May 30, 2013 #1
    The "why" questions in biology

    Usually when I ask "why" questions in biology I get answers like - because it was advantageous on an evolutionary point of view.
    But why don't I get answers like - because so-and-so part of the brain acts in so-and-so way.
    Don't we have enough knowledge to really know which part of the brain does what yet?
  2. jcsd
  3. May 30, 2013 #2
    We need a little more information to address your question. We know a lot about which part of the brain relates to this or that function, be it visual processing, appetite, hearing, movement, and so on. There's also a lot, of course, we don't know about the brain. And, yes, the evolutionary advantages of various brain and body features are a good way to infer "why" some body feature exists in some animals. Soooo, I'm not sure what your question is. Perhaps you can elaborate.
  4. May 30, 2013 #3


    User Avatar
    Science Advisor
    2017 Award

    For "why" questions in biology, we usually consider answers on one of two scales: proximate causes and ultimate causes. This distinction was originally proposed by Ernst Mayr in his classic paper, Cause and Effect in Biology.

    The ultimate causes in biology relate to answering why a certain trait or behavior evolved. However, in the case you cite, the proximate causes – those relating to the physiological mechanism for a trait or behavior – are the ones you want to know.

    It's important to note that for most complex traits and behaviors, both the proximate and ultimate causes are not well understood and are areas of active research. As DiracPool said, it's hard to say something more than that in response to your question without knowing more details about the questions you're asking.
  5. May 30, 2013 #4


    User Avatar
    Gold Member

    In addition to what everyone else said, it is not that much better of an explanation to say what parts of the brain are involved in some behavior than to just say the brain does it, in the sense that it adds little to the ability to make predictions about human behavior, or to understand how different behaviors are connected.

    If you asked how a person found his way home, it does not take much away from the mystery of it to say that the hippocampus is involved, compared to saying the brain is involved. It would be useful to know that in order to predict the effect of brain damage, for example, and it is probably an important clue to looking for a more specific explanation, but by itself, it doesn't add much. The way that conscious human decisions emerge from neurons is not well understood in anything like the level of detail needed to answer why a particular person made a particular decision at the level of neurons, or even why people on average are more likely to make one conscious decision than another.

    Evolutionary explanations are somewhat easier to come up with, but in the absence of detailed knowledge about how particular genes manifest themselves in particular behaviors through environmental interaction, there is always in principle the possibility that a behavior is a side effect of some gene selected for another reason. Also, evolutionary explanations only really work at the population level. On the individual level, there is always variation, and some of it is always being actively selected against, so evolution will never explain it.
  6. May 30, 2013 #5
    In addition there are certain "why" questions that are more in the realm of Philosophy than Science. Many questions can be broken down to more and more basic Sciences but you get to a point where you ask something like, "Why is the genetic material DNA/RNA and not XXX?" Some people may come up with certain reasons based on some Physical arguments (like Physical/Chemical properties etc) but its pretty much a Philosophical question akin to asking why is the speed of light 3e8 m/s?

    You have to remember that Science deals with Physical realities. Abstractions are used as tools to explain/model things but we cannot always answer all why-type questions with Science.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook