Talk:Cambridge change

"Just in case"
On behalf of the general audience, I have replaced the misleading and confusing expression "just in case", with its correct, and easily understood equivalent, "if, and only if" (also, in more technical writing, "if and only if"). The following explains the error:
 * Language Log: "Just in Case"
 * Southern California Philosophy for philosophy graduate students: "Just in Case".Dr Lindsay B Yeates (talk) 21:22, 9 April 2014 (UTC)

"Example" section jargon heavy and bloated with discussion that would be unnecessary even if it were intelligible
Here is the first paragraph of the section:


 * Suppose that at t1, person A is 180 cm tall and person B is 175 cm tall, while at time t2 A is still 180 cm tall but B has grown to be 185 cm tall. Since the predicate 'is taller than B' is true of A at t1 but not true of A at t2, A has changed according to the Cambridge change definition of "change"—he has gone from being taller than B to not being taller than B.

This isn't written for the general reader. Why the pseudo-precision of t1 and t2? Why the coyness of A and B? Why the wordiness of "person A" and "person B" and "A has changed according to the Cambridge change definition of 'change'"? And it isn't true that A "has gone from being taller than B to not being taller than B," since "not being taller than" includes both "being the same height as" and "being shorter than." Why use the metric system? Neither Russell, McTaggart, nor Geach would have written that paragraph. They would have written something like this:


 * Last year, 13-year-old John was five feet tall, and so was shorter than his five-foot-four mother; today, 14-year-old John is five-foot-six, and so is taller than his mother. John's mother has undergone a Cambridge change.

The current paragraph is 81 words long; mine is 35. The next paragraph runs:


 * Intuitively, however, it is only person B, and not person A, who has changed: B has grown by 10 cm, but A has stayed the same. This problem with Cambridge changes is usually thought to call for a distinction between intrinsic and extrinsic, or natural and non-natural, properties. Given such a distinction, it is possible to define "real" change by requiring that the respective predicates express a change in an intrinsic property, such as a change in height from 175 cm to 185 cm, rather than a change in an extrinsic property, such as being now taller than B.

What's with this "intuitively" business? You don't need a philosophical argument to understand that B has grown and A has not. "This problem with Cambridge changes" is not idiomatic English, and no "problem" has been identified, only the obvious fact that everybody understands that B has grown and A has not. But the fact that one person has grown and another has not has nothing to do with a Cambridge change; the Cambridge change occurs in the fact that a year ago John's mother was taller than John, and today she is shorter than John, but she has not shrunk. There is no "problem" of a Cambridge change in this instance, either, for the change itself is not problematic—it is a real change; the problem is that it is obviously not the same sort of change as John's growth. Notice that the author refers to two distinctions, "intrinsic and extrinsic, and natural and non-natural properties," but only discusses one. Obviously neither R, McT, nor G would have written such a confused paragraph. I suggest:


 * The Cambridge change that John's mother has undergone consists in the fact that a predicate true of her last year (taller than John) is not true now, and a predicate not true of her last year (shorter than John) is now true; but the change in the predicates’ truth values is not grounded in any change in her height. By contrast, the change in the truth value of last year's and this year's statement about John's height reflects his growth.  Philosophers argue that a Cambridge change is a change in an individual's extrinsic or relational properties; genuine changes involve intrinsic ones.

The current version is 99 words long, and mine 101, but no conceptual confusions occur in mine.

Here are the remaining paragraphs:


 * But this assumes that there "really" are strictly unary (non-relational) properties that, as such, are thus intrinsic. Namely, a property is intrinsic if and only if it is actually (really, analytically, fundamentally, necessarily, ontologically) unary.


 * But imagine that all metersticks as of time t2 have contracted at a rate such that B's height at time t2 would be measured as having increased by 10 cm. Imagine further that A's height has actually (really) shrunk so that it would be measured with a respectively shrinking meter stick as remaining constant from time t1 to time t2.


 * Intuitively, B's height will have remained the same whereas A's height and all ways of measuring height will have changed. In this case, it is A's height and all ways of measuring height that will have changed. The problem with the notion of "Cambridge change" is its failure to acknowledge that B's or anything else's height is relational (relative to ways of measuring height). "Height" is thus not unary and thus is extrinsic, not intrinsic.

As a summary of the matter that occurs in Section 5 of the article "Change and Inconsistency" in The Stanford Encyclopedia of Philosophy," these paragraphs leave much to be desired—I'm a philosopher, but the moment I read the word unary, I couldn't decide whether to puke or to snooze.

More importantly, nothing in these paragraphs has anything to do with any example of a Cambridge change; nothing like this figures in entries on Cambridge change found in either The Cambridge Dictionary of Philosophy or The Oxford Companion of Philosophy. If anyone wants to create a section on controversies about the notion of a Cambridge change, fine—but the matter of controversies is out of place in a section meant only to illustrate the notion and explain one elementary way to understand the example. Wordwright (talk) 19:05, 9 June 2020 (UTC)

Intro definition is too broad
The intro definition runs:


 * A Cambridge change is a philosophical concept of change according to which an entity x has changed if and only if there is some predicate F that is true (not true) of x at a time t1 but not true (true) of x at some later time t2.

But for every being that changes there is a predicate that used to be true but is no longer true. Here are some examples:


 * In 1960 Wilt Chamberlain had not played on an NBA championship team; by 1974, he had played on two.


 * In 1985, Michael J. Fox did not have Parkinson's; in 2015, he did have Parkinson's.


 * In 1964, Paul McCartney was a young man in his twenties; in 2014, he was an old man in his seventies.

The author of the definition is in good company. In The Oxford Companion to Philosophy s.v. Cambridge change the definition runs:


 * If a predicate is true of an object x at time t, but not true of x at a later time, then x has undergone what P. T. Geach has called a "Cambridge change."

I suspect that both authors wished to avoid using a contrast between a real change and a Cambridge change because that would have meant defining Cambridge change with a negative. This definition is free of that problem:


 * A Cambridge change occurs when a predicate P is true of object O at this moment (Chicago is north of me) but is not true of O the next moment (Chicago is south of me) not because O's bodily constitution is no longer the same, but because some difference in the constitution of an object G (I have moved from Atlanta to Toronto) makes logically necessary the passage of the original predicate from true to not true.

The virtue of this definition is that it captures the nature of the change and parenthetical examples help lay readers understand its nature without demanding that they try to understand a technical phrase like if and only if, and without the pseudo-precision of time T1 and T2. Wordwright (talk) 19:49, 9 June 2020 (UTC)