Category Archives: Selectors

Just For The Fun Of It: A Quibble With C.J. Date

In the previous post, I said “I get the funny feeling that for him [C.J. Date] a sentence or expression functions normally at first, but when he stares at it too long it suddenly loses its transparency….”  Here I want to unpack that doubtlessly cryptic statement a bit.  I am doing this as a kind of finger-exercise, mainly for the fun of it, and not necessarily because it will help resolve some important issue.

In “SOME OPERATORS ARE MORE EQUAL THAN OTHERS”, the second chapter of his LOGIC AND DATABASES:  THE ROOTS OF RELATIONAL THEORY, C.J. Date introduces the names NAME(‘TRUE’) and NAME(‘FALSE’) to use as symbols for BOOLEAN(NAME(‘TRUE’) ) and BOOLEAN(NAME(‘FALSE’)).  He doesn’t use, of course, the selectors I am using (to avoid ambiguity); instead, he mentions the names.  That is to say, he is talking about the symbols TRUE and FALSE.  All  page references will be to LOGIC AND DATABASES:

If p is a proposition, it has a truth value.  For the purposes of  this chapter, if p is true, I’ll denote its truth value by TRUE; it it’s false, I’ll denote its truth value by FALSE.  In computing terms, we might say we have a data type called BOOLEAN that contains just these two truth values, and the literal representations of those values are TRUE and FALSE, respectively.

(p. 42)

Then for a moment, he uses the symbols to talk about the truth values themselves.  For a moment, the symbols stop being the things seen, and function transparently as windows through which we see the things denoted.  But, feeling conflicted,  he immediately labels his use of the symbols as a kind of perhaps-understandable confusion:

We might also say, more simply but less accurately, that the legal values of type BOOLEAN just are TRUE and FALSE; strictly speaking, however, TRUE and FALSE aren’t values as such — rather, they’re literals, or symbols, that denote certain values, just as, e.g., the numeral 3 isn’t a number as such but rather a literal, or symbol (more colloquially, a digit or numeral) that denotes a certain number.

(p. 42)

But no, when ‘TRUE’ and ‘FALSE’ are being used to denote truth values, it is perfectly accurate to say that the legal values of type BOOLEAN just are TRUE and FALSE.  Likewise, when ‘3’ is being used to denote a number, 3 is a number as such.  It is as if Date were peering through the symbol-as-window, so to speak, letting it perform its function of letting us see the thing the symbol denotes….when, all of a sudden, the window going all milkily opaque on him, all he sees is the now suddenly non-transparent glass.  It is as if he said, first, ‘Cleopatra was a Ptolemaic ruler of Egypt’, but then immediately felt the need to correct himself and say, ‘Well, this is a bit inaccurate, since the name ‘Cleopatra’ wasn’t a Ptolemaic ruler of Egypt’.

Similarly, Date is brought up short when he sees the expressions x + 4 and 2x – 1 in the equation x + 4 = 2x – 1:

But the trouble is, we use the symbol “=” to mean other things as well — other things, that is, in addition to identity as such….  By way of illustration, consider the following equation:

x + 4 = 2x -1

The symbol x here is meant to denote some number, and it’s easy to see by solving the equation that the number in question is five.  But the expressions on the two sides of the “=” symbol are self-evidently not identical:  that is, the “=” symbol here does not denote identity.  Rather, it is the values denoted by the expressions on the two sides of the “=” symbol that are identical.

(p. 45)

But the “=”, rather, MATH_CONSTANT(‘=’), does denote identity, because the expressions are being used to denote the number that each expression resolves to, given the expression on the other side.  The expressions are not being mentioned — for example, the author of the equation is not talking about the fact that each expression contains the symbol ‘x‘ and references at least one number.   ‘x + 4′ names a quantity when made resolvable by equating it with ‘2x – 1′, and vice versa.   MATH_VARIABLE(‘x’) MATH_OPERATOR(‘+’) NUMBER(NUMERAL(‘4’)) MATH_CONSTANT(‘=’) NUMBER(NUMERAL(‘2’)) MATH_OPERATOR(‘*’) MATH_VARIABLE(‘x) MATH_OPERATOR(‘-‘) NUMBER(NUMERAL(‘1’)).  The quantity named by the one expression is identical with the quantity named by the other expression.  The hermeneutical principle of charity compels us to interpret the expressions this way:  otherwise, we don’t get a symbol “=” that means something other than identity; instead, we simply get a blatantly false statement when there is an absurdly easy path to getting a true statement.

Not so, then, that “…we use the symbol ‘=’ to mean other things as well — other things, that is, in addition to identity as such…”  It is used to mean just identity. It would continue to denote identity even if, perversely, we chose to mention the expressions instead of using them, for we would end up with, not a true statement that relied on a different meaning of ‘=’, but with a false statement using ‘=’ to denote identity.  Notice that I am not exercising enough control here to avoid vacillating between using single quotation marks and double quotation marks to indicate I am talking about the symbol for the equals constant.

In spite of saying a number of false things on the way towards his conclusion, it’s hard to argue with that conclusion:   But saying this does not commit me to asserting that nothing is subtly wrong with it. I am too lazy now to try to dig and see if there is a subtle, non-obvious but not necessarily unimportant way in which Date is going wrong here; and anything I came up with would probably seem rather scholastic anyhow.

To sum up:  Equality means identity.  An expression of the form x = y is almost always shorthand for one of the form value_of(x) = value_of(y).

(p. 47)

Except I would add that even in the case of expression(x) = expression(y) — for example, ‘2x -1′ = ‘2x – 1′, equality also means identity.

We can perhaps forgive Date for using (with whatever qualms) one moment the symbol as a window through which he sees the thing denoted, but seeing the next moment nothing but a window become thoroughly milky and completely opaque.  For ordinary language can start out using a name, then shift mid-stream to mentioning the same occurrence of the name by the time one gets to the middle of the sentence.  I think the example is Quine’s:

Giorgione was so called because of his size.

And on that note, I will show one of Giorgione’s paintings:

300px-Giorgione_019

and since we are now on the topic of beauty, I will go all Plato’s SYMPOSIUM on my few (0, 1, 2…) readers:

936full-a-river-runs-through-it-screenshot

Maganda si Brad Pit.  Being that gorgeous should be illegal.  I will attempt to say that in Tagalog this way:  Dapat ilegal ang magiging ganoong maganda, but that is almost certainly either ungrammatical or unidiomatic (hindi pangwikian).  Perhaps someone with better Tagalog may correct me.

Update:  12/18/2012:  Made various corrections.

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Selectors And Semantic vs. Syntactic Arguments

In case anyone wonders (“feel free to come to the point when you finally decide what it is”), the point of the following ramblings is to arrive at a place where I can make a distinction between semantic arguments and syntactic arguments.  The point of making this distinction will become clear (or not) in a later post.  Making the distinction is part of my attempting to put in my own words the argument that Tagalog lacks a subject.

In the previous post, I argued (or claimed, or made the completely unsupported, nay, spurious assertion, as the case may be) that the semantics of Maganda si Robert Pattinson can also be given by the following statement in the database language Tutorial D:

GORGEOUS_EQUALS_GORGEOUS{THIS_ONE, THAT_ONE} where THIS_ONE = PERSON(NAME(‘Robert Pattinson’))

This statement includes the Selector PERSON(NAME(‘Robert Pattinson’)).  Let me unpack a bit what this is. Before I start, I’d like to point out that I THINK that it is  legal in Tutorial D to nest one selector inside another…

NAME(‘Robert Pattinson’) is a operator or function that takes the string ‘Robert Pattinson’ and selects one and only one name.  I will take the concept ‘selects’ as primitive here.  Any implementation of this selector in a physical computer would involve shuffling around ones and zeros until the computer spits out, i.e., returns, one member of the set NAME.  NAME would include strings, but subject to certain limitations.  For example, I assume a  name would have to be, at least, less than 1 billion characters long.  NAME would also include more than strings (that is, representations of text):  a name can be selected by a sound.  So NAME(<<some representation of a sound>>) could also select the name Robert Pattinson. (The reader will notice that I have not yet decided on how to represent, in the absence of a formal selector, a name as opposed to a string as opposed to the person himself…)

PERSON(NAME(Robert Pattinson)) would take the name selected by NAME(‘Robert Pattinson’) and return a member of the set PERSONS, i.e., Robert Pattinson himself.  I don’t know how a computer would implement this operator, but a human being would be implementing that operator in the following type of circumstance:  say, I am sitting in a restaurant.  Someone in the table next to me says:

 I hereby officially declare myself to belong to Team Edward because Robert Pattinson is just too gorgeous.

One part of that utterance, the part that I hear as the word ‘Robert Pattinson’, is the end point of a long causal chain that begins, say, when the parents of Robert Pattinson, after endless wrangling and indecision, finally agree to call their baby ‘Robert’; the doctor in the Maternity Ward crosses out the ‘baby boy’ in ‘baby boy Pattinson’ and writes in  ‘Robert’ on the birth certificate (call this the ‘baptismal event’) … endless events … a director or producer chooses the person named by ‘Robert Pattinson’ to play Edward Cullen in TWILIGHT … endless events…the person sitting at the table next to me sees TWILIGHT…he reads in a magazine he buys at the supermarket that Robert Pattinson played the part of Edward Cullen…he emits a set of soundwaves at the table next to me, which in turn trigger God-only-knows what processes in my brain, until I hear ‘…Robert Pattinson….’  That entire causal chain, ending up in the wetware of my brain, selects the person Robert Pattinson.  THAT’s the implementation of the selector PERSON(NAME(<<some representation of certain sound waves>>)).  Speaking metaphorically and a bit picturesquely, the selector spits out, or returns, Robert Pattinson himself, the flesh-and-blood Robert Pattinson who lives in (I would say ‘Valencia, California’, but that is where Taylor Lautner lives)…. Speaking literally, the selector selects Robert Pattinson himself.

(See Saul Kripke, who apparently never explicitly endorsed this causal theory of reference aka selection.  Gareth Evans would apparently deem this theory, as stated by me, to be naive, but it seems perfectly intuitive to me.)

Invocations of selectors produce literals (more accurately, I guess, are literals).  So whatever else Robert Pattinson himself may be, he is a literal value.

Let me take the liberty of allowing selector invocations as arguments supplied to the parameters of functions, so that we can replace x with the argument PERSON(NAME(‘Robert Pattinson’)) in the function x EQUALS x to produce a true proposition.  Below, I have identified, ala Chisholm, propositions with states of affairs in the world:  here, with Robert Pattinson being identical with Robert Pattinson.  This proposition gives us the semantics of the utterance “Robert Pattinson equals Robert Pattinson.”

I will therefore call the invocation of PERSON(NAME(‘Robert Pattinson’)) a semantic argument.  By contrast, the invocation of NAME(‘Robert Pattinson’), occuring inside an utterance, spoken or written, is a syntactic argument.  In this way, I make sense of the semantic arguments vs. syntactic arguments distinction I puzzled over in a previous post.

I do not know, of course, whether this is the distinction that Beatrice Santorini wanted to make.

I will end by making another homage to Plato’s SYMPOSIUM, according to which interest in Robert Pattinson, Taylor Lautner, Kellan Lutz et al ultimately leads to interest in the Relational Algebra, and from there, to the Form of Beauty itself:

Robert_Pattinson_2

Wow, I love that slightly-unshaven look…(the reader may  hear a rapturous sigh…)

Now, having briefly lapsed into a lower form of eros, I will go back to eros for the Relational Algebra in connection with Semantics….

Update:  After hitting the publish button, I saw this quote from the first Jewish Prime Minister of Great Britain:

The best way to become acquainted with a subject is to write a book about it.

Benjamin Disraeli

Or blog about it at length.