axocanth
Registered Senior Member
and . . .
But that is the nonsense that requires responding to at the level I can respond to....
I was not going to respond again, but it's about time this confusion -- once again the result of philosophical illiteracy -- was straightened out once and for all.
First thing to note: Immediately after making one claim ("Newtonian mechanics are NOT false") Write4U then justifies it with another -- completely irrelevant -- claim ("They work perfectly well when applied judiciously.")
One might as well argue: "It is not false that Glasgow is the capital of the UK. It's a beautiful city."
Whether something is true or false, and whether or not something works, are entirely different questions, and must be addressed individually. It is well known that false theories, as well as true theories, can work very well.
You may have a star-headed screwdriver (or whatever they're called) in your home. It may work very well, at least when applied to screws of a certain size and design. It works far less well with screws that are too big or too small, and it works not at all with regular non-star-head screws. Moreover, and needless to say, it makes no sense whatsoever to speak of a screwdriver -- a tool or an instrument -- being true or false.
No one denies that Newtonian mechanics -- as a tool or instrument (like a screwdriver) -- works very well for certain applications. That is to say, in certain circumstances it yields predictions that are accurate -- indeed accurate enough to send people to the moon. This is not denied!
Note, meanwhile, that other theories that are regarded as false work too, to varying degrees. Phlogiston theory and geocentric theory, just to name two, also yield predictions that are accurate for some applications. The theory "All humans live to be over 100 years old" and "All mammals lay eggs" also work if you hang around with the right kind of people and the right kind of mammals: both will yield predictions that are correct in some circumstances.
Q1: Do you think "All mammals lay eggs" is true or false? How about "All humans are women"?
The latter in particular works extremely well, indeed will yield correct predictions in about 50% of cases, and will yield only correct predictions if you stick to the right "domain" (e.g. a convent for nuns).
We now come to the separate question of truth/falsity. A tool or an instrument such as a screwdriver or Newtonian mechanics, if treated as such, is neither true nor false. Tools, in and of themselves, are not the kinds of things that can be true or false; the terms do not apply. They can, however, work more or less well.
For the question of truth/falsity to even arise, something has to be asserted, you have to state something, you have to make a statement. E.g.
"This screwdriver was made in China"
Wiki states Newton's law of gravitation thus:
"The gravitational attraction force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation distance. The force is always attractive and acts along the line joining them."
The main reason this statement is now regarded as false by contemporary physicists is that the subject term does not refer, they believe there is no such attractive force. The statement therefore is exactly analogous to:
"All massive bodies are pulled towards each other by an invisible unicorn (or Santa Claus or some other fictitious entity -- see below) according to an inverse square relationship"
Here's Albert Einstein saying the same thing (my emphasis):
"We can indeed see from Newton's formulation of it that the concept of absolute space, which comprised that of absolute rest, made him feel uncomfortable; he realized that there seemed to be nothing in experience corresponding to this last concept. He was also not quite comfortable about the introduction of forces operating at a distance. But the tremendous practical success of his doctrines may well have prevented him and the physicists of the eighteenth and nineteenth centuries from recognizing the fictitious character of the foundations of his system."
- essay, "On the Methods of Theoretical Physics"
Perhaps modern physicists are wrong, though, you might reasonably retort. Perhaps Einstein is wrong, Newton is right, and there is such an attractive gravitational force. This still won't do!
Regardless of whichever ontology we nail our colors to, the laws in question do not invariably yield the correct values. This is conceded by all physicists. Some, like yourself, due to philosophical naivete, react by saying "Newtonian mechanics is still true within a limited domain."
Note first: Newton did not propose laws applicable to a limited domain. They were advanced as general laws applicable to all domains. What you are defending, then, is not Newtonian laws or Newtonian mechanics, but a revised version thereof.
What you are doing, thus, is analogous to arguing that "All mammals lay eggs" is true within a limited domain (e.g. certain parts of Australia perhaps, or a sanctuary for monotremes).
Note again: As a matter of simple logic and a little empirical inquiry "All mammals lay eggs" is false - FALSE!! Ask a logic professor at your local uni if you have any doubts. Exactly the same applies to Newtonian mechanics.
The revised version "All mammals in a limited domain lay eggs" is true, but trivially so. It reduces to the assertion that "All Xs are Y in circumstances where Xs are Y". Nicholas Rescher puts the point thus (emphasis in original):
"It may seem tempting to say that later theories simply provide localized readjustments and that the old theories continue to hold good provided only that we suitably restrict their domains of purported validity. On such a view, it is tempting to say: "Einstein's theory does not replace Newton's; it does not actually disagree with Newton's at all but simply sets limits to the the region of phenomena (large-scale, slow-moving objects) where Newton's theory works perfectly well". Such temptations must be resisted. To yield to them is like saying that "All swans are white" is true all right; we just have to be cautious about its domain limitation and take care not to apply it to Australia. This sort of position comes down, in the final analysis, to the unhelpful truism that a theory works where a theory works."
-- Nicholas Rescher, "The Limits of Science", p69
Conclusions:
* It is not denied that Newtonian mechanics works. But other theories widely regarded as false also work. False theories can work too! Newtonian mechanics is now widely regarded as being false.
* To appraise any claim about truth or falsity something has to be asserted. What exactly are you asserting about Newtonian mechanics? State it in plain English. A screwdriver asserts nothing, neither does an uninterpreted mathematical equation. Before we even begin to appraise the latter -- e.g., "h = 1/2 bd", or "e = mc squared" -- for truth or falsity you'll have to tell us first what the constituent terms mean. Meaningless claims have no truth value (T/F), a fortiori cannot be appraised for such.
* Yes, you may hear scientists make the kinds of claims that you are making, but I submit that if you do, it will emanate from the mouths of the philosophically clueless (e.g. Lawrence Krauss, Neil deGrasse Tyson, etc.). You will not, I daresay, hear such claims from more sophisticated scientists. I've noticed that you are an admirer of David Bohm. I am too! He was such a wonderfully clever and philosophically sophisticated man. See what he says on all this below.
To be continued ("message too long") . . .
