Comment by lutusp | Hacker News Reader

Comment by lutusp | Hacker News Reader

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>> There are plenty of equations, but the paper's meaning lies in its logical arguments

> This is the difference I feared. I trust, understand, and take lead of the rigorous math of the paper, you opt to follow in English arguments of what you think it's supposed to mean or apply to.

Excuse me? The articles don't prove their theses with mathematics, they prove them with logic. Equations are assistants, but they're entirely replaceable, as proven by the fact that Church and Turing used different equations in support of their theses -- articles that come to the same conclusion.

How did you miss the significance of the Alonso Church article's final sentence: "The general case of the Entscheidungsproblem of the engere Funktionenkalkül is unsolvable." Where are the equations that you think make the point better than these words? Certainly not in the article. Why didn't Church refer to an equation to support his conclusion? The answer is that his conclusion is a logical one, not a mathematical one.

In the case of Navier–Stokes, the equation is a preliminary, a self-evident statement about energy, inertia, pressure and a few other things. If it were rewritten (as it often is), the problem remained to be solved. Those who solved it didn't post a new equation, they posted a new insight.

In the relativity example, Einstein wrote an equation but didn't understand it -- his math teacher took over. Any number of equivalent expressions would have provided a basis for progress toward a more comprehensive theory. The point was the ideas, not the equations.

> ... the rigorous math of the paper ...

Nonsense. In both papers, the authors use mathematics only to support their points, in the same way that an author uses words to craft a story. If separated from the logical thread, the words (the equations) lose all meaning. This is proven by the fact that the two papers use different mathematics to support the same thesis.

But I see I'm wasting my time. Mathematics is a language, but to use it, you must have something to say.

Church and Turing did not prove their papers with the words, they described the math proving their statements in them and what that math implies (which is why the ending summary would not be math, it must already have been shown to be a summary). In however many comments you have certainly used a lot of words to describe your thought but have given nothing in the way of the math used to base the difference in your claim between that of Church/Turings.

A psychologist could just as well assert the halting problem contains math applicable to any system and therefore blue cars mathematically make us angry. The doubt would then not be on Turing but on the psychologist to show how on Earth they are mathematically linking what they are saying with what Turing actually showed. That they don't see a requirement in having the chain of math rigorously define and prove the claim when they make it is precisely why they are a soft science - they can just claim it seems to relate by less rigorous means. Defend that kind of approach if you wish, it does not make it more rigorous.

I expect we'll soon hear words about more mathematicians and scientist, related to the current problem or not, rather than math. Perhaps I've allowed myself baited by hope again on the mention of what math is needed being discussed.

> Church and Turing did not prove their papers with the words,

THAT STATEMENT IS FALSE. The two articles used DIFFERENT EQUATIONS TO SUPPORT THE SAME LOGICAL ARGUMENT. Church and Turing are jointly credited with the same logical conclusion, even though they used different mathematical arguments. NO ONE said, "Wait, the equations are different, therefore the conclusion must be different." At least no one with an education.

> ... they described the math proving their statements in them and what that math implies (which is why the ending summary would not be math, it must already have been shown to be a summary).

Church and Turing made the same logical claim, using the same words but different mathematical arguments. This places the math in a supporting role, below logical reasoning. This is true in all the examples I provided. Math is a language, but to use it, you must have something to say.

In the Relativity example I gave, Einstein's math teacher used the SAME equation to draw a DIFFERENT CONCLUSION, because EQUATIONS SUPPORT IDEAS, THEY AREN'T THEMSELVES IDEAS.

Just as with words, math equations never stand by themselves -- they support ideas, and the same idea can be expressed by different mathematical arguments. That was the point of all my examples, which clearly fell on the ears of a religious true believer.

This equation -- y = sqrt(1-x*x) -- can be taken to mean (a) pi/4 if integrated on the interval 0 < x < 1, or (b) space and time are separate dimensions, which is what Minkowski noticed and Einstein didn't. But by itself, THE EQUATION MEANS PRECISELY NOTHING -- for that, you must have ideas.

If you possessed the intellectual integrity of the average 12-year-old, you would realize that using the same words as Ernest Hemingway doesn't make you a great writer, and using the same equations as Einstein doesn't make you an original thinker. That requires ideas, not equations.

I post this for the benefit of other readers, who unlike you might have some depth of understanding, some grasp of the relation between ideas and equations.

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