A Conversation for Ask h2g2
Petty hates
toybox Posted Aug 28, 2009
You don't need to include 'mortal' in the definition of human, if you include, say, 'mammal' (which are mortal already). Or 'alive' really. That would be just redundant, and you want to get rid of redundant properties in definitions.
Petty hates
KB Posted Aug 28, 2009
As I said, it depends how comprehensive the definition is. But sooner or later, after a long, long chase through a dictionary, you'll find that mortality is one of humanity's defining characteristics.
Petty hates
toybox Posted Aug 28, 2009
Ah no, what I mean is: you don't *need* to include mortality in the definition (although you can) if you specify, say, that humans are mammals. Because mortality is already a property of mammals. Thus, 'mortal mammal' is just that same as 'mammal', really. It looks like a restriction but it isn't.
In general you (well, mathematicians ) want to keep a definition as short and economic as possible, and whatever property derives from the definition should be stated separately as a theorem.
It's like defining a square to be a two-dimensional figure with (1) four sides of equal length and four right angles, and (2) diagonals which meet in their middle at a right angle. Property (2) is redundant, so it is more elegant (although technically superfluous), to drop it from the definition and state it as a general property of figures satisfies property (1).
A petty hate for you: arguing with a mathematician
Petty hates
Malabarista - now with added pony Posted Aug 28, 2009
But isn't a good definition one that doesn't require a lot of prior knowledge?
Petty hates
toybox Posted Aug 28, 2009
In any case, not really in mathematics -- we just assume that the reader knows about all terminology which is used within the definition (they can always go and check). In real life I don't know how it works But whatever is just a consequence of the rest is usually left out.
Petty hates
toybox Posted Aug 28, 2009
Actually that's a very nice question about definitions you have. I guess it depends on context -- 'prior knowledge' is such an elusive notion!
Petty hates
KB Posted Aug 28, 2009
"Ah no, what I mean is: you don't *need* to include mortality in the definition"
Sure, you don't *need* to include mortality. But if you don't, you must be summarising or sending the reader elsewhere.
A lot depends on whether you read the Concise Oxford, Noah Webster, or the Baldrick edition.
Petty hates
toybox Posted Aug 28, 2009
Oh, and if you start playing 'define all the words which come up in the definition'... won't you come up with words defining themselves after a while?
Petty hates
KB Posted Aug 28, 2009
I use the Baldrick edition - it's so lacking in redundancies.
Petty Hate: Still don't have one.
Petty hates
Anna Siren- the heathen of the deep, according to iTunes... Posted Aug 28, 2009
Petty hate: Running all the way down Great Vic Street in Belfast [thereby rendering myself useless for the next two hours] to catch the 5.05pm bus home... only to see it pulling out as I ran up to the door out to the station! Argh.
Petty hates
pocketprincess Posted Aug 29, 2009
Before I got my car, running down Great Victoria St was a fortnightly/3-weekly pass time of mine - the clock at Robinsons used to fool me nearly every time into thinking I was too late, even though it was never ever going to be the right time. I'd see it, think "bugger" slow down cos I was too late now anyway, remember the clock wasn't showing the right time think "double bugger" and try to start running again.
Petty hate: my brain's inability to remember simple information so I get fooled the same way over and over again!
Petty hates
Anna Siren- the heathen of the deep, according to iTunes... Posted Aug 29, 2009
Is the clock on Robinson’s never right? Usually is when I use it (I think). Haven't got a car and walking is the fastest way for me to get to college even though I’m disabled- go figure...
It's an every day past time of mine... college Mon-Fri sucks.
Petty hates
KB Posted Aug 29, 2009
No, the clock on Robinson's is *always* wrong. Luckily, so are the trains.
Petty hate: watching football with people who care about it. I'm sure I could be roused to such heights of passion and fury if I tried to, but would it repay the effort?
Petty hates
Cheerful Dragon Posted Aug 30, 2009
Petty hate: Road signs that are redone in such a way as to mis-direct you, even if you know the road well. My particular gripe is the road signs on the A38 that have been redone since the M6(Toll) opened. There's one that says you should take the next exit if you want the M42 or M6(Toll), but you can only get to the M42 northbound from that exit. Then there's the roundabout that says one road leads to the M42 northbound and the other to the M42 southbound. It lies. The first road takes you to the M42 north and southbound, the second takes you to Birmingham and the M6(Toll). If it takes you to the M42 southbound it's by such a roundabout route you'd be better off ignoring it.
Hubby reckons it's a money-making ploy on behalf of the people responsible for the M6(Toll). They're trying to force people to use the road so that more money can be got out of it. I'm not saying he's right, but those road signs are needlessly misleading.
Petty hates
urchinvic - the budgies are restless Posted Sep 2, 2009
petty hate of my day- it being bright and sunny when you leave the house so you don't take a jacket and then its absolutely peeing it down by the time you reach your destination.
Petty hates
CandyMan (Wonders why Mr. X really, really want Met to watch Pirates 3) Posted Sep 3, 2009
Moving trucks stopping on a one lane road, the driver getting out of said truck and in to a forklift to move pallets while traffic builds up behind him.
Key: Complain about this post
Petty hates
- 6181: toybox (Aug 28, 2009)
- 6182: KB (Aug 28, 2009)
- 6183: toybox (Aug 28, 2009)
- 6184: Malabarista - now with added pony (Aug 28, 2009)
- 6185: toybox (Aug 28, 2009)
- 6186: toybox (Aug 28, 2009)
- 6187: toybox (Aug 28, 2009)
- 6188: toybox (Aug 28, 2009)
- 6189: KB (Aug 28, 2009)
- 6190: toybox (Aug 28, 2009)
- 6191: toybox (Aug 28, 2009)
- 6192: KB (Aug 28, 2009)
- 6193: Anna Siren- the heathen of the deep, according to iTunes... (Aug 28, 2009)
- 6194: pocketprincess (Aug 29, 2009)
- 6195: Anna Siren- the heathen of the deep, according to iTunes... (Aug 29, 2009)
- 6196: KB (Aug 29, 2009)
- 6197: Cheerful Dragon (Aug 30, 2009)
- 6198: urchinvic - the budgies are restless (Sep 2, 2009)
- 6199: CandyMan (Wonders why Mr. X really, really want Met to watch Pirates 3) (Sep 3, 2009)
- 6200: Bright Blue Shorts (Sep 3, 2009)
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