Monday, October 24, 2011

Remark 35

Remarks 33-39 address various issues regarding ostensive pointing. The following relates specifically to the first few sentences in the boxed text between Remarks 35 and 36 which address the ambiguity of the statement

That is blue.

when uttered while the speaker points at a blue vase. Is the speaker ascribing the color "blue" to the vase or indicating that the color of the vase is an example of the color called "blue"? Or more generally, when pointing to a location and asserting "That is f", is the speaker ascribing feature f to the location? ascribing f to an entity that currently occupies the location? indicating that a feature of either the location or its current occupant is an example of f? other?

One can view the use of names and words like "this" and "that" as verbal pointing, in which case such words are somewhat analogous to a type of computer programming variable called a "pointer variable" (alluded to in my discussion of Remarks 8 and 9). The value of a pointer variable is the location in computer memory (ie, the "address") of some other variable. To say that a pointer variable p "points to the variable x" is to say that the value of p is the location (in computer memory) occupied by the current value of x.

There is a issue with pointer variables that is similar to the ambiguity of verbal pointing, viz, how does one distinguish between the location of x (its address) and the occupant of that location (the current value of x). In the "C" programming language, this is done by prepending an asterisk to a pointer p to yield the composite symbol *p, which is interpreted as "the occupant of the location pointed to by p". Then the current value of the variable x can be retrieved from memory by writing either x or *p.

Given this analogy, what seems to be missing from verbal pointers such as "this" and "that" is a way of indicating the target of the speaker's verbal pointing. But such indicators aren't really missing, they're just not being used in the statement in question. To make clear what target is intended, a speaker need only augment the statement so as to make the target explicit. Eg:

That color is blue. or That vase is blue.

Assuming that whatever is in the location being pointed to is monochrome (colored object or ambient light), the first statement is unambiguous since it essentially says "the color of the occupant of the location is called "blue". However, the second sentence is ambiguous as to what feature of the occupant (in the example, a vase) is the referent (eg, it could be the vase's shape.) Thus, since the color of an object can be thought of as a feature that "occupies" the location constituted by the object, the second statement really should be:

That color on the vase is blue.

(Could it be that in some situations the problem isn't that language has "gone on holiday" but that the speaker has?)

To complete the analogy with programming pointers, one could express these augmented verbal statements symbolically by interpreting "that" as a pointer variable and indicating the intended target by prepending an identifier of the intended target. The resulting disambiguated statements can then be represented symbolically like this:

color-that = "blue"    or     color-vase-that = "blue"

These can be interpreted as "color-value in the location pointed to by 'that' " and "color-value in the location (on the object) in the location pointed to by 'that' ", respectively.

My programming days are ancient history, but I vaguely recall that if the variable x is itself an address, to call a value in the location pointed to by x you have to similarly expand the symbology to

*x = *(*p)

which in the "C" programming language is abbreviated to **p. In words, this is "the value in the location in the location pointed to by p". Comparing this with the symbolic description of the verbal pointers, the analogy appears to hold.

And just as verbal pointers distressed Wittgenstein, pointer manipulation distresses "C" programmers (at least it distressed this faux-programmer).


  1. Hi Charles

    For me, the key to W's comments on ostensive definition (OD) is that he's doing two things:

    1. Investigating the role assigned to such acts by philosophers (in particular Russell and his earlier self) concerned with explaining meaning.

    2. Describing the actual role OD plays in our lives.

    Regarding (1), OD is supposed to fix meaning unequivocally and without the need for any contextual support (or description) because it introduces one directly to the word's meaning (ie, the ostensively indicated object). It forms, as it were, a "super-connection" between word and meaning.

    His criticism of this idea centres on the fact that OD (like any other form of explanation) can ALWAYS be misunderstood. It cannot play the role assigned to it by philosophers.

    He is not trying to say that, in its everyday role, OD is faulty or inadequate. But what is needed to make OD work is significant from the point of view of theories of meaning. I think your examples from programming give a rough idea of the sorts of things that are necessary.

    BTW, I don't think "the blue is on the vase" works. The paint is part of the object, not something exterior to it (cf "the wasp is on the vase").

  2. Thanks for the comment, Philip. It surprised me because I think of that website as an electronic scratchpad rather than a blog. With the one exception of referring you to the entry on Remark 10, I have never advertised it. (As far as I know, you and Tommi are the only visitors.) In any event, your inputs will be helpful if I revise the note - which I'm inclined to do.

    The question of where color is really located is, of course, a complex and controversial topic, philosophically and technically. But my statement

    the color of an object can be thought of as a feature that "occupies" the location constituted by the object

    was intended only to support extending the analogy. Whether thinking of color like that is useful for other purposes is a separate question - and I'd tend to agree with you that in most contexts, it probably isn't.

    BTW, I'm enjoying your topical review of PI, which is (unsurprisingly) raising points I missed on my first pass and forcing me to reread the relevant sections more carefully. So, your efforts are appreciated.

  3. Hi Charles

    Actually, something a bit odd happened regarding your website. I clicked through to it via your comment on my blog and then decided to follow it as the comment about section 35 showed as being new that day - I assumed you'd revived the blog. Then a whole load of your posts showed up in my blog-roll as being newly posted. Have you moved the posts from one site to another?

    Glad you're enjoying my blog (and thanks for your comments there). I'm in the middle of preparing a series of posts on meaning and use (probably 3 of them, but we'll see) and I think (hope) I've got a much better handle now on what's actually going on.

  4. Well, since I don't think of the site as active, I haven't made much of an effort to understand how blogspot works. When I added the note on Remark 35, I had to do some reconfiguring - altho it's not clear why what I did would cause the phenomena you experienced.

    My current intent is to flag you on your blog if and when I add an entry that might be of interest to you or your readers. So, if you find more junk automatically flowing into your mailbox, you can delete the feed w/o fear of missing out on my pearls!

    Any near-term plans to post on Davidson, my obsession du jour?