1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homeopathy and the second law of thermodynamics

  1. Mar 27, 2014 #1
    Homeopaths assert that dilution of a medicinal substance in a water -alcohol mixture, followed by forceful shaking (called "succussion") would create a memory of that substance in the solution. Critics argue that shaking of liquid water is unable to create macroscopic order, as this would contradict the second law of thermodynamics. Due to gaps in my physics knowledge, I do not really understand the following statement in this regard :
    "To create order, at a macroscopic level in liquid water with all its thermal motion, substantial amounts of energy would be required. This energy cannot be derived from the chaotic thermal motion itself. This would be contrary to the second law of thermodynamics."
    The second law of thermodynamics implies, I think, that the introduction of order in a solution would cause a decrease of its entropy and a concomitant increase of the entropy in the environment. Why would forceful shaking be unable to do this ? In particular, why can the required energy not be derived from the "chaotic thermal motion" of the water molecules ?
    Thanks for any clarification.
  2. jcsd
  3. Mar 27, 2014 #2


    User Avatar
    Science Advisor
    Gold Member

    You are basically asking why shaking a pile of broken glass does not turn into a cup. Chaotic motion cannot produce a specific ordered state by chance.
  4. Mar 27, 2014 #3
    If the energy goes from the chaotic motion to some ordered form of energy the entropy is decreasing. But you can forget about all that since the water memory itself doesn't exist to begin with. Homeopathy is just a bunch of crackpot nonsense. It's not worth your time trying to "understand" it.
  5. Mar 27, 2014 #4

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    dauto is right. This is crackpot nonsense, and we don't discuss that here.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook