Logic 4 - A datum is a symbol of matter, energy, space or time, or any combination thereof, in any universe, or the matter, energy, space or time itself, or any combination thereof, in any universe.
You'll remember from Logic 1 - "Knowledge is a whole group or subdivision of a group of data or speculations or conclusions on data or methods of gaining data.". Logic 4 now gives us the definition of data and you'll notice that it is not speculation or conclusions. Data is real, concrete, objective or a symbol for something real, concrete and objective. So once again Mr. Hubbard points out the difference between facts (data) and opinions (speculations or conclusions on data), which is an important distinction as I pointed out in the first part of this series of articles.
Logic 4 also clarifies what is meant by "methods of gaining data". These must be methods that deal with symbols of matter, energy, space or time, or any combination thereof, in any universe, or the matter, energy, space or time itself, or any combination thereof, in any universe. So simple observation would fit into this as would a technique that assisted memory (your memories are symbols of matter, energy, space and time). So whatever technique the philosopher Hegel used to determine that there could only be 7 planets going around the sun (this was at a time when an astronomer had just observed the 8th planet) can be thrown out as not a valid method of gaining data. His theory was perfectly acceptable under the definition of "knowledge" as it was "speculation" or maybe "conclusions", but it is important if you want to be able to think straight to realize that it was not "data."
Mathematics can now be seen to be a valid method of gaining data, and indeed has been used for centuries for just that. However, it must be said that it is only valid when its symbol are symbols of matter, energy, space or time, or any combination thereof, in any universe. If it starts getting into the area of speculation and conclusions then it may be knowledge but it may or may not be data.
This Logic also demonstrates that although the field of psychiatry is a body of knowledge, that knowledge is not "data" but "speculation" or "conclusions", in other words, "opinion". An example of this is the theory used to justify the use of highly profitable mind altering drugs. "There is a chemical imbalance in the brain that these drugs correct." is the theory. However, there are no actual objective tests to back this up. When brains are tested for the mythical "chemical imbalance" it is never found and people are prescribed these drugs without any objective physical test being done. The fraud of ADHD is a prime example of this.
One of the few objective tests ever done to show differences between "hyperactive brains" and "normal brains" only succeeded in showing that the brains of hyperactive patients who had been on psych drugs (like Ritalin) for some years had shrunk. The moral of this story is be very wary of bodies of knowledge that contains little or no "data" and a preponderance of "speculations and conclusions on data".