Glossary
Science: (From the Encyclopedia Britannica)
Any system of knowledge that is concerned with the physical world and its phenomena
and that entails unbiased observations and systematic experimentation. In general, a
science involves a pursuit of knowledge covering general truths or the operations of
fundamental laws.
Logic: (From the Encyclopedia Britannica)
The study of propositions and their use in argumentation.
The major task of logic is to establish a systematic way of deducing the logical
consequences of a set of sentences. In order to accomplish this, it is necessary first to
identify or characterize the logical consequences of a set of sentences. The procedures
for deriving conclusions from a set of sentences then need to be examined to verify
that all logical consequences, and only those, are deducible from that set. Finally, in
recent times, the question has been raised whether all the truths regarding some
domain of interest can be contained in a specifiable deductive system.
Epistemology: (From the Encyclopedia Britannica)
The study of the nature, origin, and limits of human knowledge. The name is derived
from the Greek episteme ("knowledge") and logos ("reason"), and accordingly the field
is sometimes referred to as the theory of knowledge. Epistemology has had a long
history, spanning the time from the pre-Socratic Greeks to the present. Along with
metaphysics, logic, and ethics, it is one of the four main fields of philosophy, and nearly
every great philosopher has contributed to the literature on the topic.
Metaphysics: (From the Encyclopedia Britannica)
The philosophical study whose object is to determine the real nature of things--to
determine the meaning, structure, and principles of whatever is insofar as it is.
Although this study is popularly conceived as referring to anything excessively subtle
and highly theoretical and although it has been subjected to many criticisms, it is
presented by metaphysicians as the most fundamental and most comprehensive of
inquiries, inasmuch as it is concerned with reality as a whole.
In the business of science we often talk about a "system" and this sometimes can be confusing. (A similar mystery often surrounds the term "function" in mathematics). A system is, in fact, to quote Humpty Dumpty, `When I use a word, it means just what I choose it to mean -- neither more nor less.' A system is what you want it to be. If you want to roll a set of 10 dice to catalogue the outcome of the roll, the system is the ten dice. More importantly, the system is only the 10 dice - we allow no interaction with the rest of the world (except, of course they may bounce around and then come to rest on a table). Our system could also be all the molecules in a room and, if we wish, the containing walls of the room. Sometimes, for statistical purposes, we may define many identical systems. Take the 10 dice: To see how they behave (i.e. which faces are upright after a roll) we can roll the dice, say 100 times, and record the results. We can get the same information if we take 100 identical systems of 10 dice each and roll them each just once. The 100 sets form an "ensemble" of systems, or a "statistical ensemble." One other point: A system is not really complete unless a reference frame for the system is defined. By a reference frame I mean a coordinate system, and a statement describing the relative motion (if any) between the observer and the system being observed.
The right hand rule is used over and over again in many contexts. It establishes what would otherwise be an ambiguous orientation of direction. In three dimensional coordinate systems the first axis may point in any convenient direction (say, to the right - call it the x-direction). The second axis then points perpendicular to the first (we will draw ours upward, but downward would do just as well - call it the y-direction). The third axis (the z-axis) must be drawn at right angles to the other two, and there are two choices: Into the paper or out from the paper. Either will establish our third dimension equally well. To settle which choice to take we invoke the right hand rule. It goes like this: Point the fingers of your right hand along the x-axis, and curl them towards the y-axis. Your thumb then points in the direction of the z-axis. Here's a useful application of the right hand rule: You want to unscrew a light bulb. Which way should you turn it? All light bulbs use right hand threads. (Except, I'm told, those in the New York subway system - do you know why they use left hand threads?) Point the fingers of your right hand in the direction you want the bulb to go - out of the socket. Your fingers tell you the direction to turn the bulb. If it's a ceiling lamp you'll turn it like this D. If it's a floor lamp you'll turn it like this C. The same applies for almost all nuts and bolts, but watch out - some bicycle threads (those on the left side pedals) use left hand threads. (Again, can you figure why?)
We often like to describe the motion of, or the force on, an object that has no physical size complicating matters. A point doesn't rotate or bend, and its location is described by a single number. Such an object is often referred to as a particle.
You may not know the term, but you know what it means. Here's an example to make it clear: If I say that 6 is proportional to 2, I mean that there is some constant number I can multiply 2 by to get 6. In this case the number (the proportionality constant) is 3, since 3 x 2 = 6. In another context, if I want to relate feet to yards, I know that 3 feet equals 1 yard, or (number of yards) = 3 times (number of feet). Here the proportionality constant between feet and yards is 3.