Firstly, I never meant that it was possible for someone to actually predict the future by knowing the exact everything of everything. Firstly, it's not possible to know anything exactly, and secondly it would be impossible to store all the information held by the universe in anything smaller than the universe. Each peice of information in your record would also need to be recorded elsewhere in your record. In fact, all the information in the universe is recorded - as the universe. Furthermore, it's a contradiction in terms to measure something in an instant - to measure, you must interect, which requires time and therefore change. You cannot say that anything particular is, only that it changes in whatever way.
ryanwh, I'm talking about physics here, not biology. You can't measure someone's rashness exactly (by statistics, yes, but not in the way that you measure temperature). But the body is an engine and a machine. All the factors that make you up as a person have to exist. Fairly obvious, no? And if it exists, you can measure it, (can in theory). When you're angry, it's beacuse of the levels of whichever chemicals in your brain. What you have in your head is a thought engine. By knowing exactly every concrete piece of information about you, (that is, not abstract information), and the exact information about every particle that will come into contact with you, I could say exactly what you're going to do. It has nothing to do with logic. People do not operate on a level of pure logic anyway. If you take any system - for instance, the sun and earth, you can look at the potential of that system. To take a far more simple example, look at Schrodinger's Cat. Because of the configuration of that system - that is, that there is a cat, a box, a gun - you can say that the system has the potential for the cat to be dead, for the cat to be alive. Similarly, the solar system has potential for a certain number of acts. The only flaw is that there is no such thing as a closed system - the earth might be hit be a metorite, for instance. So if you include the amount of data you process, you might include the nearby solar systems, and all the atoms of all the meteorites out there. But what if a metor outside these solar systems entered, stuck one of the ones you've measured, and knocked in into the earth? You'd have to expand your records to include the whole visible universe.
Remeber, I never said any of this is possible. I just said that it is. Everyone is subject to it, everyone is a result of it. Essentially, it makes no difference at all. Our percieved free will is still there - we are all indivudual, and every decision we make is of our own doing. But they're a result of a secular, (in the true sense of the word), process, and therefore limited in their potential scope.