MicroPilot:
<font color="blue">The term "tractor" is also sometimes used to describe trucks that pull trailers. </font>
You are correct, of course, that the word symbol tractor is used for road tractors pulling trailers, a/k/a semis. It is also, as has been mentioned by a few posters, used to point to other classes of objects. However, in the context of what we are talking about here, the class of objects we are referring (pointing) to (trying to define) derives from the class of objects to which the term, in the sense we are using it, was first applied, to wit: traction engines used for agricultural purposes. All of the things we use and call tractors evolved from that original class of objects to which the word symbol, in the sense we are using it, was first applied. In addition, a road tractor pulling a trailer meets only one of the criteria possessed by that class of objects. A road tractor does not meet the criteria of operating as a universal power source to run other tools and implements (a quality possessed by all of the original class of objects to which the word symbol was first applied), therefore, both in context and by definition is excluded from that class of objects. Remember, that the closer other classes of objects are to the defining characteristics of the class being defined, the closer those other classes are to the defined class. Put more simply, if it walks like a duck, swims like a duck, looks like a duck and lays duck eggs we may reasonably conclude it is probably a duck.
What I am looking for is to see if any of you can think of any class of objects which meets the definition I have proposed to wit: <font color="blue">“my contextual definition of a tractor is a mechanical, self propelled, universal power source used to power other tools and implements”</font>, yet would not generally be thought of as a tractor (in the sense we are using the word symbol).
Et al:
Some of you complained that thinking about my post gave them a headache – I sincerely apologize. Of course, whether such an effect is a function of the density of synaptic connections per cubic centimeter of neural mass, or some other unknown cause, I cannot say. In any event, this is a tractor site for people interested in tractors. At least to my way of thinking it seems it might be of at least some small interest to at least a few members to agree on what we are talking about when we use the word symbol.
Rat:
You are absolutely correct that anyone can use any word symbol to point to any class of objects (or even no class of objects at all, i.e., words treated, within the brain, as things in themselves, rather than pointers to objects a/k/a floating abstractions). And if one has no concern to enhance <font color="blue">“clearer and more precise human communication” </font> then the issue of definition is, obviously, of no importance. You are right. Of course, the logical end of such a position is to reduce human beings to point of having to communicate through pointing at things and grunting at each other. Back to where we started.
dixiedrifter:
You seem to agree with my definition. At least my reading of what you posted was that you said the same thing in different words. Or, am I missing something?
JEH