A wonderful lecture by Lawrence Krauss


BaalChatzaf

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Lawrence Krauss is the niftiest lecturer in physics since Richard Feynman. Have a look!

Ba'al Chatzaf

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Really good so far, I'm halfway through. While I'm thinking of it, any thoughts on David Harriman’s contention that “space is not a thing which can curve”? And that Kant is the father of modern physics?icon_rolleyes.gif Reference his lecture The Crisis in Physics-and its cause… I don’t think a free transcript is available unfortunately.

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Here's a great (brief) excerpt:

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BTW the Harriman lecture is freely available here: http://www.aynrand.org/site/PageServer?pagename=reg_ls_physics

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? And that Kant is the father of modern physics?icon_rolleyes.gif Reference his lecture The Crisis in Physics-and its cause…

this is total nonsense of course. Kant held that Newtonian Physics was a synthetic apriori certainty. Modern physics has many "fathers" among whom are Maxwell, Boltzman, Planck and Einstein. None of them were explicit Kantians, certainly not Maxwell. As far as science goes, Kant stopped at the east side of the English Channel.

Some advice: Do not take anything by Peikoff or Harriman as serious physics.

Ba'al Chatzaf

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Some advice: Do not take anything by Peikoff or Harriman as serious physics.

I don’t think they’re particularly helpful for understanding Kant either. They just trot him out as an all purpose bogeyman, it gets embarrassing. Schrodinger_warning.png

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Some advice: Do not take anything by Peikoff or Harriman as serious physics.

http://www.solopassion.com/node/7373

http://www.amazon.co...ASIN=0451230051

Be afraid. Be very afraid.

Why? I recall what Karl Freidrich Gauss once said (in German of course): Where the metaphysicians are original they are wrong, and where the metaphysicians are right they are unoriginal.

Nothing these two loo loos say will change the fact that induction is not a universally valid or sound means of inference. At best, it is a heuristic.

My remark about Messers Harriman and Peikoff still stands until proven wrong.

Ba'al Chatzaf

Edited by BaalChatzaf
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Nothing these two loo loos say will change the fact that induction is not a universally valid or sound means of inference. At best, it is a heuristic.

My remark about Messers Harriman and Peikoff still stands until proven wrong.

Ba'al Chatzaf

I took a quick trip in the TARDIS, and all I can say is that within five years Harriman will have won the Nobel prize, and his acceptance speech will make specific reference to “that loser schmuck Bob Kolker, alias Bald Chutzpuff[sic]” and other “Kantian Popperian Fruitpies” in terms I can only characterize as opprobrious. Thence comes, at last, your Warholian quarter hour.

tardicon2.gif

BTW there’s another Krauss lecture up, it’s pretty similar but different enough to be worth a watch.

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Edited by Ninth Doctor
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Nothing these two loo loos say will change the fact that induction is not a universally valid or sound means of inference. At best, it is a heuristic.

My remark about Messers Harriman and Peikoff still stands until proven wrong.

Ba'al Chatzaf

I took a quick trip in the TARDIS, and all I can say is that within five years Harriman will have won the Nobel prize, and his acceptance speech will make specific reference to “that loser schmuck Bob Kolker, alias Bald Chutzpuff[sic]” and other “Kantian Popperian Fruitpies” in terms I can only characterize as opprobrious. Thence comes, at last, your Warholian quarter hour.

Tell that to the guys who discovered black swans and albino crows.

Ba'al Chatzaf

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Tell that to the guys who discovered black swans and albino crows.

Ba'al Chatzaf

Funny you bring them up, they're part of Harriman's target audience:

blackswan.jpgalbinocrow.jpg

But mostly:

lamb.jpg

They picked out focus group members from confirmed fans of James Valliant's The Passion of Ayn Rand's Critics.

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Here's a great (brief) excerpt:

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BTW the Harriman lecture is freely available here: http://www.aynrand.o...=reg_ls_physics

That is so fracking brilliant! Krause is a marvelous lecturer.

Ba'al Chatzaf

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"... the fact that induction is not a universally valid or sound means of inference..."

How was this truth arrived at? Induction? Deduction? Sensory perception? Some other method?

I came up with one (count it) induction with true premises and a false conclusion. The old one, you know, about white swans, but there are black swans. That is sufficient to falsify the proposition that all inductions with true premises lead to true conclusions.

Do you have any idea how a universally quantified proposition is falsified? Apparently not.

Ba'al Chatzaf

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Oh, god. And you want for an example of nonsense from philosophizing physicists?

What parts are nonsense?

Just the title.

Give it a watch, it’s really good, much easier to understand than Hawking. Apparently he doesn’t think much of string theory.

http://www.amazon.com/Hiding-Mirror-Alternate-Realities-Wonderland/dp/0143038028/ref=sr_1_4?ie=UTF8&qid=1291254703&sr=8-4

His Star Trek book is great, even if you're not into Star Trek (I'm not, too unintentionally Pythonesque).

Not that old Dr. Who is any better...

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I came up with one (count it) induction with true premises and a false conclusion. The old one, you know, about white swans, but there are black swans. That is sufficient to falsify the proposition that all inductions with true premises lead to true conclusions.

Whoop-de-do. Who has claimed that all inductions with true premises lead to true conclusions?

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"... the fact that induction is not a universally valid or sound means of inference..."

How was this truth arrived at? Induction? Deduction? Sensory perception? Some other method?

I came up with one (count it) induction with true premises and a false conclusion. The old one, you know, about white swans, but there are black swans. That is sufficient to falsify the proposition that all inductions with true premises lead to true conclusions.

Do you have any idea how a universally quantified proposition is falsified? Apparently not.

Ba'al Chatzaf

Once again, Bob refuses to address the fact that just as there are valid and invalid forms of deductions, there are valid and invalid forms of induction. This has been pointed out to him repeatedly.

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"... the fact that induction is not a universally valid or sound means of inference..."

How was this truth arrived at? Induction? Deduction? Sensory perception? Some other method?

I came up with one (count it) induction with true premises and a false conclusion. The old one, you know, about white swans, but there are black swans. That is sufficient to falsify the proposition that all inductions with true premises lead to true conclusions.

Do you have any idea how a universally quantified proposition is falsified? Apparently not.

Ba'al Chatzaf

Once again, Bob refuses to address the fact that just as there are valid and invalid forms of deductions, there are valid and invalid forms of induction. This has been pointed out to him repeatedly.

In other words when an induction is right it is right an when it is wrong it is wrong.

In the case of the famous white swan induction, what error was made in forming the generalization that all swans are white? What rule of generalization was violated?

Contrast this with Wiles proof for Fermat's Last (so-called) theorem: It turns out when his first proof was vetted he had slipped in an assumption that was not in the hypothesis of the theorem. When then was pointed out he want back to the workshop and banged out a proof the following year that the vetting committee has found to be correct. We are not talking about simple proofs here. Wiles acceptable proof ran several hundred pages long and it required specialists in number theory and modular group theory to comb through it looking for fleas.

When deductions go wrong it is because

1. A rule of inference was misapplied or

2. An assumption as made that is logically equivalent to the thing to be proved (begging the question).

Competent mathematicians almost never commit the type 1 error but even the best mathematicians slip in an assumption that begs the question. This is almost always inadvertent.

Let me give you a simpler example. Prop I in Book I of Euclid's Elements. This theorem says an equilateral triangle with a side equal to a given line segment can be constructed. The proof comes down to drawing two circles that intersect, the point of intersection is the third vertex of the desired triangle. What is the problem. No where in the axioms or the postulates is it assumed that when two circles apparently intersect there is a common point which lies on both circles.

Another example in in the proof of the congruence theorems for triangles. Two triangles that agree on two sides and the angle between them are congruent. (Side Angle Side). What is the problem. The proof assumes the triangles can be moved in the plane in such a way that the sides and the angles are preserved under the motion. True enough, but what is the problem? No where in the postulates or the axioms is it assumed than any objected (point, line etc) can be moved in a plane without distortion or change. In short, Euclid begged the question.

THAT is how deductions go wrong. Not because the logic was bad (generally) but because an assumption, an additional hypothesis is brought in unconsciously or inadvertently.

In the case of the white swan generalization the general conclusion reached (all swans are white) was strictly according to the rules, so we have a "legal" induction which starts out with true instances and ends up being factually incorrect. Which proves that a kosher induction can sometimes lead to an incorrect conclusion.

Here is a more "scientific" example of an incorrect induction: Heat. Heat was originally thought to be a very lightweight non-dense fluid that was not visible to the eye but occupied the little spaces between the parts of solid or liquid bodies. This fluid went by the name Caloric. It was assumed to flow spontaneously from where it was to where it wasn't. Was this a silly idea? Not really. We do perceive the transfer of heat as a kind of flow. Furthermore the hypothesis that heat is a substantial but not readily perceivable fluid accounts for the expansion of liquids and solids when they get hot. The caloric the liquid or solid gets oozes into the small spaces between the particles of the substance and pushes them apart. So the hypothesis that heat is a fluid has some consequences and these check out on observation. So what is wrong with Caloric. The first indication that Caloric was not conserved as it would have to be if it were a substance (a substance cannot come out of nowhere) was an observation made by Count Rumford in 1789. The boring of canon barrels heated them up. The barrels could be bored again and again and they would heat up again and again. Where is the heat "fluid" coming from. This line of investigation lead to the motion theory of heat. Heat is the motion of the particles (molecules) that make up matter (solids, liquids and gases). The alternative to Caloric was part and parcel of the atomic or molecular theory of substantial matter, a hypothesis which we accept today and is very well supported.

To make a long story somewhat shorter the motion theory of heat accounted for everything that caloric did and did not lead to the embarrassment of heat coming from Nowhere. The conservation problem was ultimately solved by people like Joule who realized that heat was a form of energy and energy is conserved. Did the people who created the Caloric theory commit any gross illogic? Not on the face. The theory of caloric was reasonable to the extent that it made some predictions that were verified empirically and could be grasped by anyone who could feel the heat "flow" from a hot body. It was only by looking more closely at the matter that the conservation problem arose and was eventually fatal to the caloric theory.

More examples of perfectly reasonable inductions that were wrong: The phlogiston theory of combustion. It was believed that when combustion occurs a substance, phlogiston leaves the body. Is the theory unreasonable? No, not on the face of it. When a piece of wood or paper is burned it shrivels, shrinks and crumbles to ash. Something that gives the body its rigidity or shape has departed. How was phlogiston disproved? By measuring very, very carefully. The French chemist Lavoissier measured all the products of combustion -- not only the ash, but the water vapor and other combustion residuals. He weighed them carefully and found the sum of the stuff to be greater than the weight of the original body prior to burning. In short, something was added, not subtracted from the stuff that was burned. The English chemist Priestly discovered what the something was. It was a gaseous stuff that was released by some chemical reactions involving mercury. This gas when exposed to burning stuff made it burn faster and brighter. Further more the air we breath contains this stuff and that is what accounts for combustion. The stuff is Oxygen which not only supports combustion and the release of heat from burning material but also accounts for rotting and souring of organic matter. In German the name of Oxygen is SaurStuff (sour-stuff). Recapitulate: Lavoissier discovers something is added by burning (not lost) and Priestly found out what the stuff was. So the phlogiston hypothesis was displaced by a better hypothesis that accounted for more facts. Again, there was nothing illogical about the phlogiston hypothesis. It fitted some of the observed facts about burning. There is a loss of moisture and the production of heat when something burns. But careful measurement reveals that in burning there is a net gain of material. Oxygen accounts for the gain in the weight.

I have produced several examples of "reasonable" inductions. Inductions based on some evidence that on later examination turned out to be wrong. In these inductions, reason was never violated outright. And there were facts that supported these erroneous inductions. What does that show us: Induction, even when done reasonably and logically starting with with true assertions can lead us to false general conclusions. Ergo induction lacks the main virtue of deduction. When deduction starts with true premises it ALWAYS ends up with a true conclusion.

Ba'al Chatzaf

Edited by BaalChatzaf
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Geez, Ba'al, is this going to be your Introduction, or your Chapter One?

Tony

No. I just wanted to present some "scientific" examples of induction that went awry. Not all induction is of the simple minded enumerative type, as in the "all swans are white" kind of induction.

I rest my case. I have presented two "scientific" inductions that were perfectly kosher in terms of the reasoning and the evidence available at the time they were made. They were "good" inductions that led to false conclusions. Hence induction is not a valid form of inference. It can start off with true assertions and end up with false conclusions. I further showed how deductions can go wrong. Among competent mathematicians the error is the introduction of hypotheses or assumptions not previously stated, a common form of "begging the question". At no point was there a step contrary to the rules of logic, yet the proof is rejected. Why? Proofs must state what assumptions are being made. No fair sneaking in an extra assumption, even if it is done by mistake. The examples were of perfectly valid deductive inferences but improper proofs of theorems (improper for the reasons stated).

Ba'al Chatzaf

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In other words when an induction is right it is right an when it is wrong it is wrong.

It has been pointed out to you repeatedly on multiple threads that induction by enumeration is an invalid method since it fails to distinguish between causal/essential/necessary and accidental attributes. The example all swans have necks was provided to you as a valid induction. Your repeated refusal to acknowledge such corrections to your position is evasion. What is your motivation for refusing to listen to people who attempt to communicate with you and for insisting on attacking straw men? Fear? Laziness? The comfort of an easy target? You are moderately intelligent, Bob. Surely you could have something more interesting to say if you were to deal with the actual position being argued for rather than some silly bogeyman. Or no?

Edited by Ted Keer
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