As a general matter, you can't prove a predicate true or false by automatic means. Logic programming is just as "artful" as imperative or functional programming, because they all run into the same problem: it's impossible to tell the difference between long-running and infinite computation. The question of algorithms for general logic was explicitly addressed as the Entscheidungsproblem, meaning decision problem, which was independently proven undecidable by both Turing and Church:
>> As a general matter, you can't prove a predicate true or false by automatic means.
Not in the general case, sure, yet in practice I'm sure we've all written plenty of code that terminates just fine. [Edit: I'm talking about imperative as well as logic or functional programming code].
The question then is- what does it mean when a program terminates? In the case of principled approaches like logic or functional programming, you have a pretty good idea what that means (e.g. a logic program proves a theory true or false). When an imperative program terminates, it's a very hairy affair to say what, exactly, termination means.
[Edit 2: Actually, if you think about it, there's nothing we can really achieve in the general case (including machine learning; see language learning in the limit). In practice, on the other hand, we're doing things, alright - by continuously relaxing principles and fudging limits as necessary (see PAC learning)].
The drawback of hash tables is that they're bad for inexact matching. Likewise, when I go to the library, I usually go to the section I'm interested in and let my eyes wander. So something that pseudorandomly organizes books but lets you find them by exact title quickly is not so good.
Risk of borrowers defaulting is the entire ethical justification for lending with interest. Collateralization reduces the risk of the loan, but doesn't eliminate it; after all, cars lose value over time, and businesses may or may not be able to sell assets for enough to cover their liabilities. Indeed, the closest you get to eliminating the risk of a loan is having the federal government guarantee it, so...
Ironically, the postapocalyptic world will probably still use US dollars. And when it turns out that not enough physical dollars survived the apocalypse, dollars will be the way credit is accounted, with whatever dollars remain being used to periodically reconcile accounts.
In this case it's probably justified: one of the hallmarks of "modern" bubbles, or at least of modern speculative hype that doesn't work out, is that renaming a company based on the hype increases its stock price without any change in the fundamentals. This has a long history, including companies during the dotcom bubble increasing their stock price by giving themselves techy names.
I was playing Pai-Gow poker at a casino with my parents and some friends. The game has side bets, which pay out if you get a good hand, independently of whether you win or lose, and (inversely) proportionate to the probability of the hand. By the numbers they're terrible bets (while Pai-Gow has the, I think, third-lowest house edge, after craps and blackjack), so my friend and I don't bet them, but my parents do. My friend got a great hand, full house maybe, and my dad said, "bet you wish you'd made the side bet," and we both said, "no, we don't."
Keynes sort of sums up this sentiment, just replace economist with philosopher:
>Practical men who believe themselves to be quite exempt from any intellectual influence, are usually the slaves of some defunct economist. Madmen in authority, who hear voices in the air, are distilling their frenzy from some academic scribbler of a few years back.
The bottom line is, all "practical" viewpoints begin from some particular way of looking at the world, which usually gets hammered out in philosophy. In this sense, I find that pragmatism is usually just someone taking for granted the etiology of their own ideas, which makes pragmatism one of the least interesting positions.
Obviously I don't know what you in particular believe, so I'm just talking about the kinds of people who I've personally seen advance these kinds of positions.
A good point. One thing: I've studied philosophy quite a lot, and even I don't know, or have forgotten, the meaning of 'etiology'. So I assume there's no chance the person you're responding to knows what it means. It's technical philosophy jargon.
Let's imagine that I'm a government that reserves the right to be sole issuer of my country's currency (though for political reasons I've delegated that power to a government-sponsored enterprise whose leadership I appoint). Now let's say I also issue securities denominated in that money. From my perspective, what's the difference between money and claims on money? From a holder's perspective, what's the difference between them? Even the obvious difference, one has yield and one does not, is pretty misleading, since the interbank rate tracks the securities rate.
https://en.wikipedia.org/wiki/Entscheidungsproblem