If you want to look at how badly the casual use of such terms can go, look at what happens when a clever but ignorant person writing some paper or book in the humanities tries to frame their very likely crap theory in that same language. I could have used the prime example of that, psychology, which should never, in the first place, have gotten into the category of science because it could not and still does not have the ability to practice scientific methods on its subject matter. None of the "social sciences" can, nothing dealing with the internal mind does.
Here is something I posted three years ago dealing with just one of those misused words.
When You Say "It Exists" What Do You Really Mean?
Or, more often these days, when someone says something "doesn't exist"?
I think it was a hot afternoon in the fourth grade, in a room silent except for the rubbing of graphite on paper, that, as I wrote the word, I suddenly realized I couldn't say what the word "when" means. It stopped me short as I started trying to think of how I would explain what the word means. As I came up with several attempts, only to realize they weren't adequate, I started laughing uncontrollably. I never explained why. Luckily, our teacher had a rather sharp sense of humor, herself, so I didn't get into trouble. Maybe she thought it was the heat.
We throw around so many words we couldn't possibly define, many of those as common place and high up in the corpus of words by frequency of use. I'd guess a lot of those would be as hard to define, many, such as the articles, are especially abstract in denotation though seldom misused. Except in writing. It's my experience that, looking at something a week after your final edit that it will be the prepositions and conjunctives that you neglected to change. Here is part of what Eddington wrote about one of those words in his lecture, "The Concept of Existence" from The Philosophy of Physical Science
I find a difficulty in understanding books on philosophy because they talk a great deal about "existence", and I do not know what they mean. Existence seems to be a rather important property, because I gather that one of the main sources of division between different schools of philosophy is the question of whether certain things exist or not. But I cannot even begin to understand these issues, because I can find no explanation of the term "exist".
The word "existence" is, of course, familiar in everyday speech; but it does not express a uniform idea - a universally agreed principle according to which things can be divided into existing and non-existing. Difference of opinion as to whether a thing exists or not sometimes arises because the thing itself is imperfectly defined, or because the exact implications of the definition have not been grasped; thus the "real existence" of electrons, aether, space, colour, may be affirmed or denied because different persons use these terms with somewhat different implications. But ambiguity of definition is not always responsible for the difference of view. Let us take something familiar, say an overdraft at a bank. No one can fail to understand precisely what that means. Is an overdraft something which exists? If the question were put to a vote, I think some would say that its existence must be accepted as a grim reality, and others would consider it illogical to concede existence to what is intrinsically a negation. But what divides the two parties is no more than a question of words. It would be absurd to divide mankind into two sects, the one believing in the existence of overdrafts and the other denying their existence. The division is a question of classification, not of belief. If you tell me your own answer, I shall not learn anything new about the nature or properties of an overdraft; but I shall learn something about your usage of the term "exists" - what category of things you intend it to cover.
It is a primitive form of thought that things either exist or do not exist; and the concept of a category of things possessing existence results from forcing our knowledge into a corresponding frame of thought. Everyone does this instinctively; but there are borderline cases in which all do not employ the same criteria, as an example of the overdraft shows. A philosopher is not bound by traditional or instinctive conventions to the same extent as a layman; and when he similarly expresses his knowledge in this primitive frame of thought, it is impossible to guess what classificatory system he will adopt. It would be rather surprising if all philosophers adopted the same system. In any case I do not see why such a mystery should be made of it, nor how an arbitrary decision as to the classification to be adopted has come to be transformed into a fervid philosophical belief.
I do not want to make sweeping charges on the basis of a very limited reading of philosophy. I am aware that in the recondite works the meaning of the term is sometimes discussed. But, after all, philosophers do occasionally write for the layman; and some of them seek to repel the scientific invader in language which he is supposed to understand. What I complain of is that these writers do not seem to realise that the term "exist", if they do not explain the meaning they attach to it, must necessarily be as bewildering to the scientists as, for example, the term "curvature of space", if left unexplained, would be to the philosopher. and I think it is not an unfair inference from this omission that they themselves attach more importance to the word than to its meaning.
It is not every sentence containing the verb " to exist" that troubles me,. The term is often used in an intelligible way. for me ( and, it appears, also for my dictionary) "exists" is a rather emphatic form of "is". "A thought exists in somebody's mind," i.e. a thought is in somebody's mind - I can understand that. " A state of war exists in Ruritania," i.e. a state of war is in Ruritania - not very good English, but intelligible. but when a philosopher says "Familiar chairs and tables exist", i.e. familiar chairs and tables are...., I wait for him to conclude. Yes: What were you going to say they are? But he never finishes the sentences and I do not know what to make of it.
Speech is often elliptical, and I do not mind unfinished sentences if I know how they are meant to be finished. "A horrible noise exists" presumably is intended to be completed in such form as " A horrible noise is- disturbing me". But that is not how the philosopher intends me to complete his unfinished statement. "noises actually exist " - and I really have no idea what completion he does intend. I myself, when I am not intimidated by the existence* of critics determined to make nonsense of my words if it is possible to do so, often say that atoms and electrons exist. I mean, of course, that they exist - or are - in the physical world, that being the theme of discussion in the context. We need not examine the precise ellipsis by which a mathematician says that the root of an equation exists, when he means that the equation has a root; it is sufficient to say that he has no idea of putting forward a claim to include the root of a mathematical equation in the category of things which philosophers speak of as "really existing".
In the preceding chapters I have discussed a number of things which exist in the physical universe; that is to say, that are in, or are parts of the physical universe. We have seen that "to exist in", even in the equivalent expression " to be part of", is not free from ambiguity, and is made definite only by the conventions discussed in connection with the concept of analysis. The question whether the physical universe itself exists has not arisen. I have, in fact, avoided saying that it exists - which would be an unfinished sentence. Ordinarily it would be unnecessary to be so particular. The existence or non-existence of things is a primitive form of thought; and, if I had used the term, it would mean no more than that I was forcing our observational knowledge into such a frame** as it is forced into several other frames that we have discussed. Knowing, however that as philosophers we must seek to get behind these forms of thought, I have thought it best in this book to avoid introducing it even temporarily.
* No; you have not caught me this time. The critics intimidate me just as much, whether philosophy concedes to them "real existence" or not.
** If we wish the assertion to mean more than the expression of a primitive form of thought, we say "really exists".
Of course, my motive in typing this out is related to the past several posts on the debunking of morality, free will and consciousness. It is also related to the frequently angry or mockingly derisive claims of the non-existence of God or any other entity that the materialistic atheist takes up so much of our attention with. In her popular book, A History of God, Karen Armstrong introduced many people to the rather startling fact that many religious mystics have held that God doesn't exist, or, rather, God doesn't merely exist, that to say that God exists is to put the category of existence over God, they reject the human practice of assigning a defined limit to God who is held to be above all possibilities such as those. I am sure that atheists with a broad enough corpus of locutions would mouth the logical positivists' pat phrases declaring that idea to be nonsense and so meaningless. I take that to be a demonstration of their being naive of the fact that logical positivism died a rather definitive death as a viable intellectual frame years and even decades before most of them were born.
In what I've been interested in, the moral and political entities - equality, rights, moral obligations, free will, consciousness - all of those are non-material entities, all of them, admittedly, not demonstrable with science or mathematics, none of them having any physical, but moral consequences in the world, which also entirely elude the one and only net that modern atheism asserts exists, causation as can be demonstrated with physical science. Their one and true oracle whose decisions are absolute and true.
Only, as Eddington pointed out the variable rigor with which people make definitive statements about things existing depends on context. If those same materialists have a notion that they are the victims of an infringement on their rights, the reality of those things are asserted by them to be so concretely existing that everyone must act, now, to grant them relief. They demand their rights to everything from suppressing all public talk of God and religion, parents talking to their own children about religion and to their right to have you cast your next ballot for an atheist candidate, whose right to your vote, even against your will, seems to be held to have an absolute existence. Though, as I've mentioned, that would seem to be a right that is, somehow, absent from Biblical fundamentalists or even moderate or liberal evangelicals. I'd love to have someone assert their rights to public office in an appropriate grouping of atheists.
Funny how often it's "different" when it's their preferences in question. Where do their strongly held, scientifically asserted negations go then? Did their rigorous assertions that free will, morals, etc. are illusions if not delusions, really exist?
Update: When I say that equality, rights, moral obligations, have no physical effects in the world, I didn't mean that there weren't the most obvious physical effects which the human species have produced when the reality of those is denied. Piles of corpses result when the existence of those is rejected, though the possible non-existence of the similarly immaterial motives in murdering tens and hundreds of millions don't seem to trouble materialists or alleged non-materialists to the extent that they prevent murders. I have come to find that it is far easier to disbelieve that the allegedly religious mass murderer's professions of faith are sincere than that they somehow forget what they allegedly believe to obviously violate it. People who don't follow the words of Jesus to not kill and oppress people should be suspected of not really believing he spoke with divine authority. That murderers might have no scruples about lying when it serves their purpose doesn't seem an unreasonable idea, to me.
Update 2016: Why should I be embarrassed about having a really good ear and a really vivid memory of what I heard in the 4th grade? I seldom forget what I heard, that's a good thing, except when it's crappy pop music of the kind that Stupy can process.