Prompted by a conversation I had not so long ago, I will postpone my entry-in-progress in favor of this one. I'll finish and post that one later.
Also, if I haven't mentioned this before, I will be attempting to stick to the ITRANS transliteration of Sanskrit. However, I will be changing a few rules to suit me (ITRANS: saMskR^ita, my rendition: saMskRta), and as such, to prevent confusion, I will utilize Google/Blogger's unicode devanaagarii/Hindi rendering.
Metaphysics is a branch of Western philosophy which originally sought to answer questions relating to the nature of reality. After science developed and branched off, "metaphysics" continued to attempt to answer questions relating to reality that were not answerable by science, probably due to the fact that science was empirical in its process.
The interesting thing about metaphysics is that in conjunction with religion, it essentially becomes mysticism. Metaphysics, at least in the Western Classical sense, is about coming to terms with the nature of reality and life as a whole, and so requires "following" it, or applying knowledge gained in the study of metaphysics to one's actual life. In order to fully appreciate metaphysics, the argument can be made that you must practice, not just study.
However, this is not always the case. I'll illustrate an example from Western tradition, before I go into the relevance in Hinduism. While people may fully follow the Hermetica and its associated practices (what exactly they are I don't very well know), it was not uncommon for people to study it without the intention of applying it. Passing interest in it is one matter, but it is quite another for someone to study it with the intention of better understanding the imagery and inspiration in the Tarot.
(On a different note, Tarot actually isn't Egyptian, as is commonly claimed. Most of the imagery, aside from Christian references, comes from the Hermetica, which is considered akin to the Egyptian book of Thoth. The Moors translated the old texts and re-introduced them to Europeans via Spain. Cards came from China, and the Tarot imagery and reading techniques itself developed in Italy.
The Tarot: History, Symbolism, and Divination - Robert M. Place)
To take a different example, let's take a look at the Hindu philosophical schools. One of the three pairs of sister-schools is "saaMkhya-yoga" (Devanaagarii: सांख्य-योग). SaaMkhya is usually translated as "enumeration." It describes a dualist view on reality, consisting of puruSha (Deva: पुरुष) and prakRti (Deva: प्रकृति), with puruSha being "consciousness" and prakRti being "matter/nature." From there, it goes on to describe how puruSha interacts with prakRti, i.e. how consciousness interacts with and is entangled in matter, via the senses and mind.
I am making it a point to note that in saaMkhya-yoga, the "consciousness" present in all of us is often referred to as a "soul." However, this is not a "soul" by Western standards. What is considered the "soul" by Western standards differs from the "draSTuH" (Deva: द्रष्टुः, "seer/one who is seeing") referred to in the yoga sutra's. In the West, ideas like the "mind," "intellect/reason," and "thought" are elements of the soul. In Hindu thought, the mind is material in nature, as are thoughts and intellect. Only pure, unadulterated consciousness is considered the "soul."
Yoga, however, is the application of that knowledge in order to free one's self from the bondage of matter. Yoga, whose English cognate is found in the word "yoke," expounds on how one can go about separating the inner consciousness from the outside world. As the consciousness cannot be turned off, when it no longer gets input from the senses it turns instead to itself. This "self-awareness" process is what yoga is about. By today's lingo, we'd call this "raaja yoga" (Deva: राज योग) and its process that of "meditation"; the popular use of the word "yoga" revolves around haTha yoga (Deva: हठ योग) which focuses on different postures (aasana's, Deva: आसन's) to make the body full of vigor.
Another example, for those of you who know or would like to research stuff on your own, is that of the nyaaya and vaisheSika (nyaaya, Deva: न्याय ; vaisheSika, Deva: वैशेषिक), the sister schools of logic and proper metaphysics, respectively.
There's a good deal of practicality in studying something without the intention of applying it. It allows you to access related studies and become deeply involved with them and remain focused with them. Studying chemistry allows you to deal with particle physics and biology, without having to become a chemical engineer. You would hardly expect to see yogi's at proper debates between the different schools of Hindu philosophy. The yogi's would pretty much sit and say, "Why bother arguing each other? Why not see for yourselves?" Advocates of saaMkhya would take over for them and debate. And before you say that they were right, think about this: had they not participated in those debates, there would be very sources alive today from which we could understand their school in any tangible way. Participation in debates is what legitimized them, financially and academically. It's well and good to stick to you guns, but if everyone is just sitting and meditating, who's going to provide a means for them to continue doing that? And while we can learn about meditation from Buddhism and Tantra, Yoga is an entirely different beast, especially when you get down to the nitty-gritty details of life, souls, methods, etc.
In addition, for those that merely dabble in studying metaphysics and/or mysticism, without actually practicing it, there's also a purpose. They bring the ideas of the few to the mainstream, regardless of how muddled and riddled-with-defects they may become.
The Beats' understanding of Eastern spirituality was much more accurate than the Hippies' (which isn't saying much, but it's really the fault of the Easterners). However, it was the latter who made much of the overall message available to the general population. And, once you have the idea and a few terms in people's vocabularies, you don't have to do much for people to genuinely become interested and take hold of practice.
Another example was Einstein's Theory of General Relativity. Even before it was "properly" confirmed by an eclipse in Australia in 1922, Eddington's calculations from a solar eclipse from Africa brought initial news of the theory's success (despite Campbell's news of failure). British papers - and, indeed, newspapers across the world - ran headlines about how his theory proved what they thought previously of gravity as wrong. Einstein, and his theory, were household names across the globe, despite the fact that most people didn't know what in the universe it was actually saying.
And so, on many levels, it's important to understand that the study of metaphysics without any touch of practice, while seemingly contradictory, provides many uses.
And, the next time I'm cursing some fallacious, self-proclaimed know-it-all, I'll do my best to remember that even incorrect knowledge finds ways to teach people the truth.