In academic context, especially physics: “It is obvious” and “handwaving”
The first silences any dissent by implicitly marking anyone doubting the intuition as stupid. The second marks the argument as imprecise and thus implicitly worthless though the “handwaved” argument might be a nice idea with the need to be enhanced.
I feel like the first one is at least partially unfair. It seems more like a noisy signal, since there are many appropriate uses of the phrase, such as: “It is obvious that the trajectory of this projectile as it passes through the atmosphere of Earth can be calculated with sufficient precision to predict its landing zone and evacuate persons in the area, therefore we will not elaborate on this. We will instead concentrate our efforts on methods of early detection and measurement of such dangerous objects.”
The alleged “obvious” statement draws from established and relatively confirmed experience, and may be assumed to be a fact that every physicist / astrophysicist / relevant expert already knows.
The same goes for most semantic stop signs. “If you want to reduce caloric intake, you should drink less soda.” Another way to state what you just said is “In the past we calculated similar trajectories, so we can be sure to calculate the trajectory of this object now.” The use as semantic stop sign comes from the fact that if something is obvious it does not need to be stated. The only people surprised and intimidated by stating that something is obvious are the exact people who do not think a point is obvious.
The use as semantic stop sign comes from the fact that if something is obvious it does not need to be stated.
There are times when it’s useful to state things that everyone present already knows. Most of the uses of “it’s obvious” fall out of these cases.
For example, the rules of formal argument in an academic context might normally require each step to be given in full; but for pedagogical purposes it’s not always useful to do that. The phrase there means you’re temporarily lowering the level of rigor to make the argument clearer or to save time, and that’s a useful thing to have in your toolbox.
Alternately, if you’re making a complex argument with a lot of moving parts, salience issues often come into play; your audience might need to be periodically reminded of certain simple facts, but stating them without qualification might be viewed as condescending. “It’s obvious that...” in this case serves as a social lubricant, a way of saying “I know you know this”.
I don’t know. I read and writ a lot of math (where “obvious” is probably most likely to be overused) and I do try to double-think every time I write it down. But when reading, it means to me “this statement SHOULD be obvious, if it’s not, then you’re missing something and you should probably reread what just happened.” If it doesn’t say that and just states the result I am less likely to give it a second thought, perhaps ironically. If they don’t say “obvious” then maybe they’re quoting some theorem I don’t know and that often isn’t very relevant unless I need to know every detail of this. If they do say “obvious” then they’ve at least judged that theorem (or definition or whatever) to be sufficiently basic as to be worth my while learning. Not only that, but if I think something seems obvious and the author thought it was sufficiently obvious to call it obvious, then I’m probably not missing anything subtle!
It safeguards against people thinking you’re stupid or signals that changing your mind requires strong evidence. It could also warn other people you might consider them stupid if they speak against your claim without evidence. Also what lmm said.
I don’t usually see “handwaving” used quite that way. It marks the argument as imprecise, yes, but not worthless. Physics lecturers who say “and I’m waving my hands a bit, but here’s the basic concept, and you’ll work through the algebra in the homework and see for yourselves that it comes out as you’d expect” aren’t saying you shouldn’t listen to them; they’re saying that there are steps being left out and you shouldn’t 100% trust the conclusion until you’ve checked all the steps.
Obviously I agree with you on “it is obvious”, though.
We used to deliberately switch “it is trivially obvious to the most casual observer that …” to “it is casually obvious to the most trivial observer” in order to remind ourselves that “obvious” doesn’t always mean what it means.
I once saw a heated argument between two bell labs scientists where A was shouting at B “you are wrong, you are just wrong” and after 1⁄2 hour of loud discussion in A’s office the door opened again at which point I heard A now shouting at B “your point is just trivially obvious.” I thought that was pretty good, moving a PhD Princeton Astronomer from “wrong” to “trivially obvious” in less than one hour. Agile minds!
In academic context, especially physics: “It is obvious” and “handwaving”
The first silences any dissent by implicitly marking anyone doubting the intuition as stupid. The second marks the argument as imprecise and thus implicitly worthless though the “handwaved” argument might be a nice idea with the need to be enhanced.
I feel like the first one is at least partially unfair. It seems more like a noisy signal, since there are many appropriate uses of the phrase, such as: “It is obvious that the trajectory of this projectile as it passes through the atmosphere of Earth can be calculated with sufficient precision to predict its landing zone and evacuate persons in the area, therefore we will not elaborate on this. We will instead concentrate our efforts on methods of early detection and measurement of such dangerous objects.”
The alleged “obvious” statement draws from established and relatively confirmed experience, and may be assumed to be a fact that every physicist / astrophysicist / relevant expert already knows.
The same goes for most semantic stop signs. “If you want to reduce caloric intake, you should drink less soda.” Another way to state what you just said is “In the past we calculated similar trajectories, so we can be sure to calculate the trajectory of this object now.” The use as semantic stop sign comes from the fact that if something is obvious it does not need to be stated. The only people surprised and intimidated by stating that something is obvious are the exact people who do not think a point is obvious.
There are times when it’s useful to state things that everyone present already knows. Most of the uses of “it’s obvious” fall out of these cases.
For example, the rules of formal argument in an academic context might normally require each step to be given in full; but for pedagogical purposes it’s not always useful to do that. The phrase there means you’re temporarily lowering the level of rigor to make the argument clearer or to save time, and that’s a useful thing to have in your toolbox.
Alternately, if you’re making a complex argument with a lot of moving parts, salience issues often come into play; your audience might need to be periodically reminded of certain simple facts, but stating them without qualification might be viewed as condescending. “It’s obvious that...” in this case serves as a social lubricant, a way of saying “I know you know this”.
It is rarely useful to say that something is obvious.
I don’t know. I read and writ a lot of math (where “obvious” is probably most likely to be overused) and I do try to double-think every time I write it down. But when reading, it means to me “this statement SHOULD be obvious, if it’s not, then you’re missing something and you should probably reread what just happened.” If it doesn’t say that and just states the result I am less likely to give it a second thought, perhaps ironically. If they don’t say “obvious” then maybe they’re quoting some theorem I don’t know and that often isn’t very relevant unless I need to know every detail of this. If they do say “obvious” then they’ve at least judged that theorem (or definition or whatever) to be sufficiently basic as to be worth my while learning. Not only that, but if I think something seems obvious and the author thought it was sufficiently obvious to call it obvious, then I’m probably not missing anything subtle!
I agree. Obvious is a two-place word—obvious to whom?-- and that fact isn’t obvious;.
It makes it explicit that you’re skipping some steps.
An explicit, but polite, way to say that you’re skipping some steps: “I’m skipping some steps here.”
Saying that something “is obvious” can come across as insulting the competence of anyone in the audience who doesn’t take it as obvious.
It safeguards against people thinking you’re stupid or signals that changing your mind requires strong evidence. It could also warn other people you might consider them stupid if they speak against your claim without evidence. Also what lmm said.
I don’t usually see “handwaving” used quite that way. It marks the argument as imprecise, yes, but not worthless. Physics lecturers who say “and I’m waving my hands a bit, but here’s the basic concept, and you’ll work through the algebra in the homework and see for yourselves that it comes out as you’d expect” aren’t saying you shouldn’t listen to them; they’re saying that there are steps being left out and you shouldn’t 100% trust the conclusion until you’ve checked all the steps.
Obviously I agree with you on “it is obvious”, though.
We used to deliberately switch “it is trivially obvious to the most casual observer that …” to “it is casually obvious to the most trivial observer” in order to remind ourselves that “obvious” doesn’t always mean what it means.
I once saw a heated argument between two bell labs scientists where A was shouting at B “you are wrong, you are just wrong” and after 1⁄2 hour of loud discussion in A’s office the door opened again at which point I heard A now shouting at B “your point is just trivially obvious.” I thought that was pretty good, moving a PhD Princeton Astronomer from “wrong” to “trivially obvious” in less than one hour. Agile minds!