1. Definition: A sign is a thing that can be sensed that turns the mind to think of something else. SIGN NATURAL SIGNCONVENTIONAL SIGN INTENDED NATURAL SIGN SIMPLY NATURAL SIGN ARBITRARY SIGN CUSTOMARY SIGN Natural sign: a sign in which the connection between sign and signified is established by nature. Conventional sign: a sign in which the sign and signified are related only in the mind. If the connection comes about through custom, it is customary, but if it is purposely chosen, it is arbitrary. If a natural sign is used intentionally to communicate, it is intended, otherwise, it is natural simpliciter.

2. NATURAL SIGN INTENDED NATURAL SIGN SIMPLY NATURAL SIGN Definition: A sign is a thing that can be sensed that turns the mind to think of something else. Natural sign: a sign in which the connection between sign and signified is established by nature. Intended natural sign: a natural sign which is intentionally used to communicate. A natural sign simpliciter : a natural sign which is not used intentionally to communicate. Stock examples: an inn keeper keeping a fire lit so travellers will know it is warm inside the inn; an animal groaning so its herd knows it is hurt. Stock examples: smoke signifying a fire; tracks signifying an animal; an involuntary groan signifying pain CONVENTIONAL SIGN

3. CUSTOMARY SIGN ARBITRARY SIGN Definition: A sign is a thing that can be sensed that turns the mind to think of something else. Conventional sign: a sign in which the connection between sign and signified is related only in the mind. Customary sign: a conventional sign in which the connection between sign and signified is established by custom. Arbitrary sign: a conventional sign in which the connection between sign and signified is established by choice. Stock examples: a diamond ring signifying engagement; “chair” signifying an artifact made for sitting. Stock examples: Stars and Stripes signifying the American Union; “Au” signifying the element Gold NATURAL SIGN

4. Definition: A sign is a thing that can be sensed that turns the mind to think of something else. SIGN SIMILITUDE TOKEN Similitude: a sign which signifies through the likeness it bears to the thing signified. Token: a sign which does not signify through a likeness it bears to the thing signified. Stock example: a red octagon bears no resemblance to the command to stop, so it is unable to turn the mind to that command through its appearance. Stock example: a portraiture looks like a certain person, and so through this resemblance, it can turn the mind to think of that person.

5. Logicians care about words, concepts, and the reality those concepts represent. What is a word? (By “word”, we mean the spoken word. We will talk about written words later.) First of all, it is a sound, but not just any sound, but one produced by the voice. The definition of a word starts off “a vocal sound…” But there are lots of sounds I can make with my vocal apparatus – a grunt, a burp, a trill, as well as a word. How is a word different? Well, we have been talking about signs…. Does that suggest an answer?

6. SO a word is a vocal sound, but it is not just a random noise. It is also a sign. A snore might be a sign too, a sign that a man is sleeping. So the next step in finding a definition is to ask, what kind of sign is a word ? Is it natural or conventional?

7. SO a word is a vocal sound that signifies, but it does not signify naturally. It is conventional. Is it arbitrary or customary? Can you give examples of words that are arbitrary, and ones that are customary? Most words come about by accident: no body sits down and decides to invent them. But there are quite a few words that are arbitrary. When such words are invented, we say that a words has been “coined”, and its definition “stipulated”. Professional associations do this all the time: politicians, scientists, medical personelle, trademen, etc. So we cannot limit words to only customary signs.

8. So a word is a vocal sound that signifies by convention. Is it a similitude or a token? Most words are tokens: “red” in no way looks red, nor does the word “kilogram” weigh anything. But again, there are a few words which break the rule. Can you think of any? Such words are call “onomonapia.” SO once again, we cannot put “token” in our definition of words. What we are left with is that a word is a vocal sound that signifies by convention.

9.  “Words are vocal sounds that signify by convention.” To finish our discussion, we have but one thing left: what do words signify?  Obviously, a word can signify anything, but perhaps before they signify anything at all, they first signify an idea. In other words, the purpose of a word is that it allows me to vocalize a sign which turns another persons mind to think of the idea that I am thinking about.  When two people talk, and thereby come to share the same idea, they are united together in their thoughts. They are comm unicating.  “Words are conventional vocal signs that signify concepts, so that men can share their thoughts.”

10.  First of all, where do concepts exist? They are not things “out there”, running in the woods or fields, or flying about in the air. A concept exists only in the mind.  Do concepts exist in books? Not really; after all, a book contains written words, which are nothing else than signs of the spoken word – they are not concepts per se.  Do concepts exist in spoken language? Not really, after all, a conversation or speech contains spoken words, and these are not concepts, but signs of concepts.  Concepts, therefore, must exist in the soul*, that is, somewhere within us, in our psyche, within our principle of life, there within our conscious selves.

11. Logicians do not use the word “soul” with any religious or moral implications. Metaphorically, the soul is “the breathe of life.” Here, the word “soul” signifies nothing other than the source of life and its functions, namely, that animating principle or actuating cause of an individual organism’s life. In this sense, plants have souls, animal’s have souls, anything that lives has a soul. Is the soul “spiritual”? By this we mean, is the soul immaterial, a substance not composed of matter, a substance without dimensions. Perhaps some souls, maybe even all souls, are spiritual. But logicians do not assume such a doctrine. Does the soul continue after death, going to heaven or being reincarnated? Maybe some do, but again, logic does not take any position on the question. That is a question for philosophers and theologians to discuss using logic to guide their discussion. Does the soul even exist? Once we strip away all the assumptions about the soul, the answer is obvious. Organisms are alive, aren’t they? If by “soul” we only mean “principle or cause of life” than of course the soul exists. Logic does not need to get into the problem any deeper than that. The job of logic is to show us how to solve problems; its job is not to give the solutions to those problems.

12.  Now the soul is the principle of many powers and functions in the body, and so, in a sense, it has many parts. Which part of the soul contains our concepts?  Certainly, they do not inhabit our nutritive powers, our growth powers, or our reproductive powers, for plants have powers of nutrition, growth, and reproduction, but they do not harbor concepts within their souls.  Concepts do not inhabit our sense powers either. The eye does not form a concept, nor does the ear, or nose, or tongue, or skin. Even the part of the brain that receives the nerve impulses from the exterior sense organs, even this part does not have concepts. It only has the experience of sensation.  Concepts do not even exist in the imagination. After all, an imagination is just a conglomeration of sights, sounds, smells, tastes, and feelings. One cannot image a concept, but we certainly can represent a concept with an imagination. Where in the soul, then, do concepts exist?

13.  Concepts exist in that part of the soul called the “intellect.” This part is called the intellect from the Latin word intellectus, (translation: “understanding”) because this part of the soul is where understanding occurs.  Now it is important to recognize that the intellect is not the same as the brain, any more than sight is the same as the eye. The brain has many parts and functions which have nothing to do with the intellect.  There is another reason we do not want to say that concepts are in the brain. Is there an organ in the brain where the mind operates when it understands something? Perhaps, but perhaps the mind operates apart from the brain, on a “higher plane.” That question is hotly debated.  Logic leaves that question for others to answer, but it can provide the tools to help that discussion proceed in the most rational way.

14.  It is also important to recognize that the intellect is not the same as the imagination. The imagination imagines things, that is, it takes the experiences of sensation and reorganizes them into new experiences. One can take the image of a man’s shape, and the image of gold‘s color, and combine them to imagine a golden man.  The imagination imagines things, but the understanding understands things. These are quite different functions. What does a golden man look like? That is something the imagination can handle. What is justice? That is something that cannot be imagined. What is the meaning of “animal”? Again, one can imagine the shape, color, and motion of an individual animal, but that is quite different from the meaning of animal. The imagination of an animal cannot resemble both an elephant and a flea, but the meaning of animal will include both elephants and fleas.  During our lives, we discover new species of animals that we have never before imagined, and yet we know these new organisms are in fact animals because even when they do not look like what we imagine an animal to be, we understand that they fit what we understand animal’s to be. We must not confuse imagination with understanding.

15.  So a concept is in the intellect, the part of the soul that understands. Words signify these concepts. The vocal sound “animal” signifies the concept of animal. This concept is sometimes called the “mental word”, but this word does not have a sound or a look or a smell or a taste or a feel. So what are these concepts?  Once again, our notion of “sign” can be helpful here. A concept is a sign in the intellect. Most concepts are signs of things. When we hear “dog”, we turn our attention from the vocal sound to the concept of dog. But the concept of dog is then able to turn our minds to a dog itself, such as Lassie or Rover -- in fact, to any dog whatsoever.  A few concepts are not signs of realities; they may be signs of other concepts or of imaginations.  The next question is this: what kind of sign is a concept, natural or conventional?

16.  Conventional signs do not have to signify what they are signs of. Take the emblem of a country, its flag. It is possible for the legislature of that country to decide to abandon its flag, and adopt a new sign. It is even possible to assign that flag to represent something else, another country, a boat, a season.  Are concepts conventional signs? Can the concept of a dog signify anything other than a dog?  When a child sees several dogs, the child notices a likeness between all these dogs, and forms a likeness of them in its intellect to signify any of the real dogs. This likeness is a dog, but it is not a physical dog. Since it must signify any variety of dog, it can look like a beagle, collie, retriever, poodle, terrier, spaniel, shepherd, or boxer. So it cannot be an imagination of the sensible features. It is an idea, a mental likeness of the conceptual features. It is a natural similitude of a dog.