Tuesday, May 7, 2013

"Using as"

I can use a fork as a backscratcher or my thumb and forefinger as the prongs of a slingshot.

I claim that when I do so, there isn't a backscratcher or a set of prongs that comes into existence when I do so.

For consider the three possibilities on which it is correct to say that prongs come into existence:

  1. The thumb and forefinger cease to exist and prongs come into existence, made out of the former digits.
  2. A set of prongs comes into existence in exactly the space occupied by the thumb and forefinger, and are made out of the same matter as the prongs.
  3. The thumb and forefinger are both a thumb and forefinger and a pair of prongs after the transformation.

The first option is obviously false.  I didn't temporarily come to have only eight fingers when I did it for the purposes of the photo.

The second option doesn't match the how we talk.  I would say: "I used my fingers as the prongs of a slingshot."  But according to (2), I had the prongs of a slingshot right there in the very same region of space occupied by my fingers--why didn't I use them as the prongs of a slingshot, since they are surely at least as usable for that purpose.  Or did I use both my digits and the prongs as prongs?  But I need only two things for slingshot prongs, not four.

Moreover, as I am typing with both hands, surely the prongs no longer exist.  When did they cease to exist?  Right after the shot?  But when I took the picture, I didn't actually take a shot--I only used my fingers as prongs for show.  (I did take a shot on other occasions, shooting a little fuzzy ball from the kids' craft drawer.)  When I relaxed the fingers?  But why not, instead, think of the relaxed fingers as folded prongs?  A slingshot could, after all, fold.  It's not like I destroyed the prongs when I relaxed my fingers--they're ready for convenient use at any other time.  Yet if they do continue to exist, do I have forty-four other pairs of prongs on my hands (granted, 25 of the pairs--the ones with one finger from one hand and the other from the other--can only be used by having a friend pull back the pocket or by pulling the pocket back with the teeth) if I form the odd ambition to use a different pair every day for the next forty-four days?  And if the prongs ceased to exist, will the very same pair of prongs be resurrected the next time I use my thumb and forefinger as prongs?  These questions seem silly, and their silliness suggests that they are predicated on a mistake.

The third option fits better with our "use as" talk.  I used my fingers as prongs, and I used the prongs as prongs, but there aren't four things there, because the fingers were prongs.  But we get the wrong modal properties.  For suppose that I decided to reinforce the prongs by supergluing steel rods to them.  The steel rods would come to be a part of the prongs, but they wouldn't come to be a part of the fingers.  Hence the fingers are not identical with the prongs, by Leibniz's Law.  

All this fits with common sense.  I used fingers as slingshot prongs or a fork as a backscratcher, and there were no slingshot prongs or a backscratcher there.

But can this line be maintained?  Suppose I cease to use the fork as a fork, and start to use it exclusively as a backscratcher.  Suppose in our culture, everybody owns a backscratcher, as our greeting ritual is a light scratching of each other's backs.  And backscratchers look just like American forks.  Surely what I would have would be a backscratcher.  Yet, surely, whether a backscratcher comes into existence shouldn't depend on how permanently it is used as such.  Still, that seems to be how we talk.  If all we are doing is descriptive metaphysics, we may stop here.

But if we want to do more gutsy metaphysics, we might at this point question the initial intuition that I had a fork there.  Perhaps the fundamental concepts are not of backscratchers or slingshots (or prongs thereof) or even forks, but of using some thing or things (particles, say) as backscratcher, slingshot (or prongs thereof) or fork. To use as a backscratcher is like to dance a waltz--if we want to do serious metaphysics, we shouldn't ask where the token backscratcher is in the using or where the token waltz is in the dancing.

Rob Koons has defended the idea that artifacts are token social practices. What I am saying is quite similar, except that I do not want to identify the artifacts with social practices. But all the reality there is in artifacts is the reality of things used as, or meant to or designed to be used as something or other.


Unknown said...

Clear argument! Here's an objection. It seems like the Leibniz's Law argument against identifying the prongs with the fingers goes something like this:

(1) The prongs are such that possibly, they have steel rods as parts.
(2) The fingers are not such that possibly, they have steel rods as parts.
(3) For any x and y, if x = y and possibly Fx, then possibly Fy.
(4) Therefore, the prongs are not the fingers.

I have two concerns with this argument:

First, (3) isn't obviously true. "Possibly ..." might be a context like "believes that ...". In that case, Leibniz's Law doesn't get us to (3), for the same reason that "John believes that Santa Claus is real" doesn't get us to "John believes that Kris Kringle is real" --- even given the premise that Kris Kringle = Santa Claus.

Second, to get the inference to (4), we need (1) and (2) to have the form "X is such that, possibly, FX". But maybe its logical form is really: "For some unique x, Gx and possibly, for some unique x, Gx and Fx". I.e., perhaps what we're really saying is: "There is something which uniquely has the property of being the prongs and possibly, there is something which uniquely has the property being the prongs and it has steel rods as parts." If that's the logical form of (1) --- and it seems to me that plausibly it is --- then we don't get a valid inference from (1) and (2) to (4).

I don't see that we have strong reason to believe that both of these suggestions fail. So that should leave the "the prongs = the fingers" option as a live possibility.

Alexander R Pruss said...

One can substitute rigid designators for one another in modal contexts.

Well, let Sam be the prongs and Jim the fingers. Then Sam = Jim. So, if Sam possibly has these steel rods as parts, so does Jim.

Dagmara Lizlovs said...

Here's a few precautions with those rubber bands.

1. Don't snap yourself with them. Ouch, that can really, really hurt.

2. Keep them pointed in a safe direction at all times. This is mandatory for all shooting items.

3. Realize that many schools consider rubber bands used as impromptu sling shots and also spit balls to be in the same class of weapons as assault rifles with high capacity magazines and do not distinguish between the two.

4. Above all don't take the rubber band slingshot to school. You will be guilty of a totally unforgivable crime for which you can never be punished enough - violating the zero tolerance weapons policy.

5. Now if you want to really do something that will get you into trouble, Instructables has these tips:


MacGyver or A-Team anyone?

Unknown said...

Dr. Pruss,

That response depends upon the availability of rigid designators "Sam" and "Jim" such that (for instance) some entity Sam is not mereologically continent across possible worlds. I'm not sure what strong reason we have to think that there are any rigid designators of that kind. The alternate view --- that nearly all noun terms are descriptivist --- seems viable. So if we have good reason to believe in artifacts, and we don't have strong reason to disbelieve the sort of descriptivist view just mentioned, doesn't that leave the "fingers = prongs" alternative as a plausible view?

Alexander R Pruss said...

You can do the same thing I do with rigid designators with bound variables.

(x)(y)(IsTheseProngs(x) and IsTheseFingers(y) → x=y)
we should be able to derive:
(x)(y)(IsTheseProngs(x) and IsTheseFingers(y) → (F(x) iff F(y)))
for any intensional (but maybe not hyperintensional) formula F.

Alexander R Pruss said...


And by the same token, if you've done martial arts, you shouldn't bring arms and legs to school?

Unknown said...

What reason do we have to think that "... possibly has steel rods as parts" is an intensional formula but "... is believed by Tom to be real" is not an intensional formula? It looks like they may work the same way: "Tom believes that P" = "P is believed by Tom" ascribes a monadic property (being believed by Tom) to P, and "Possibly, P" = "P is possible" also ascribes a monadic property (being possible) to P.

Dagmara Lizlovs said...


"And by the same token, if you've done martial arts, you shouldn't bring arms and legs to school?"

Don't even mention it. It is best not to give some people ideas. Some things are getting there. Take for example this:

" In December 2010, freshman Andrew Mikel II was kicked out of Spotsylvania High School for the remainder of the school year under a charge that the “spitwad” incident constituted “violent criminal conduct” and possession of a weapon. School officials also referred the matter to local law enforcement for criminal prosecution."

Here is the article:


Back in my time in school, the teacher would just use the paddle, period.

Or this:

"Other cases include school officials expelling a 6-year-old girl for bringing a plastic toy gun to school, issuing a disciplinary warning to a 5-year-old boy who brought a toy gun built out of Legos to class, and expelling a fifth-grade girl who had a “paper” gun with her in class. “These incidents, while appalling,” notes Whitehead, “are the byproducts of an age that values security over freedom, where police have relatively limitless powers to search individuals and homes by virtue of their badge, and where the Constitution is increasingly treated as a historic relic rather than a bulwark against government abuses.” Whitehead concluded his remarks by noting that if adopted, SB 1058 will be a positive first step in pushing back against the tyranny of zero tolerance policies in the nation’s schools by excluding childish behavior from punishment while also targeting malicious intention as the crucial factor in determining appropriate discipline."

Full article here:


Back in my day when I was that age the teacher either ignored it or confiscated the item.

Or how about a 5 year old with a plastic soap bubble gun:

'. . ."I'll shoot you, you shoot me, and we'll all play together," the kindergartner says.

The next day, that remark -- which was made innocently, according to the lawyer for the girl's family, who related the story -- landed the young central Pennsylvanian child in the principal's office.

Soon after, she was sent home after being issued a 10-day suspension for a "terroristic threat,". . . '

Full article:


We all know 5 year olds can be little terrors. But terrorists?

I did come across this obituary:


He will be missed by all of us who knew him.