This entry is continuation of the last one. It was getting a bit too long but I want to deal with another aspect of it. One of these days I am going to organize these into a proper blog so that people can leave comments, but first I have to get WordPress running on my server.
Last Darwin Day (Feb. 12) the creationists at my school had a booth set up and I spent some time chatting with them. Typical of creationists, they were profoundly ignorant of real science but firmly believed in their standard creationist talking points, one of which is that the laws of thermodynamics would make evolution impossible. I addressed this below, but I want to expand on a claim made by the woman I was talking to, that “Laws” are called laws because they are absolutes that are never violated, while a theory is always tentative.
To briefly repeat what I said before, a theory can contain laws, but a theory can never become a law. A law is a short statement of a specific principle, while a theory is a comprehensive description of a class of phenomena. Think of it this way: A law will fit on a t-shirt, but a theory fills up books.
As to the claim that laws are absolutely inviolable, let’s consider thermodynamics again. Thermodynamics describes the aggregate behavior of a very, very large number of particles (atoms or molecules). For example, just 12 grams of carbon contains Avogadro’s Number of atoms, 6.022 × 1023. Thermodynamics is essentially statistical in nature, but because the number of particles is so large, their behavior is quite predictable. This is predicted by statistics.
The Law of Large Numbers states that the more events you have, the closer their average behavior will be to the most probable outcome. As an example, suppose you are flipping a coin. The statistical odds for any flip are exactly even: heads or tails. If you just flip one coin, you cannot predict the outcome at all. If you flip ten coins, you will get five heads and five tails more often than the other possible combinations, but they will still show up often, and so you probably won’t get exactly half heads and half tails. However, if you flip a million coins you can very confidently predict that you will get 50% heads and 50% tails, with extremely high precision. Also, your arm will be very tired.
Because we typically deal with amounts of matter that contain an unimaginable huge number of particles, we always see the most probable behavior. But if we had a system that only contained a few molecules of gas, we would see most of the laws of thermodynamics being violated. The First Law, conservation of energy, would still hold, but the Second Law (the entropy thing) would fail regularly, as would Boyle’s Law, Charles’s Law, and the Ideal Gas Law. Of course, in this case it doesn’t even make sense to define thermodynamic properties such as temperature and pressure, as they are statistical averages themselves and only make sense with a large number of particles.
The point here is that “Laws” are not inviolable. In fact, many of our scientific “laws” are just approximations. The Ideal Gas Law, for example, describes something that doe not exist in nature (that’s the “ideal” part). It is, however, a pretty good approximation for many real gases. So why do we call it a law when it is not always right? Becaause it fits on a T-shirt!
tshirt