Logic! (And why it is liked/disliked)

[Killer Angel]

Logic is good, but if it's not controlled by moral principles, it can create horrible results.

[Eloel]

That is where it gets to the point that you out logic them when you shouldn't. If you truthfully think you are correct, go ahead. But if there is a sliver of doubt, then tell them you are not absolutely sure, but <insert argument here>. That way, you are telling them that it is only your answer, and not necessarily the correct one.

My argument usually goes, "I think X because Y, which is because Z, which follows from T. If you'd like to disagree with X, please point me to the point where I'm wrong."
Most people can't - even if there's a glaring error in logic.

Perhaps they just stop to escape your, perceived, self-centred nagging?
Sometimes it is just not worth it to argue with someone who you feel never backs down on any issue, regardless how wrong that person is. A bit similar to the racist granddad on family gatherings whom none engages in conversation on said issue to preserve some peace of mind.

I see, you are scared of logical arguments. Happens.

[Elder Tsofu]

I see, you are scared of logical arguments. Happens.

Not really, I just pass on information regarding how people can perceive someone differently than the person in question perceive themself - and as a by-product provided an alternate explanation of the events described.

[Zrak]

My argument usually goes, "I think X because Y, which is because Z, which follows from T. If you'd like to disagree with X, please point me to the point where I'm wrong."
Most people can't - even if there's a glaring error in logic.

So, basically, you are bragging to us about how your interlocutors are poor debaters?

[Killer Angel]

I'll try to explain better my opinion on the matter.

Why i like logic.
It's elegant, it's intelligent, it serves to lead us to the truth. Aristotelian logic is amazing.
So, any debate with logic involved, is to me fascinating.

Why i dislike it.
Cold logic is inhuman. If it's not supported by empathy and moral principles, logic leads to aberrations.
I'll leave aside real life and historical examples (there's plenty of them), and I'll limit myself to fictional ones, just to give a mild idea.
When Spock says that the needs of the many outweigh the needs of the few, it's logical. The possible implications are clear.
If you want to reach an objective, applying only cold and rationale logic to eliminate what's slowing down you, well, you have HAL 9000.
And this speech, shows clearly what happens, when the logic of the profit is involved.

And you know that some applications of "cold logic" in real life are far worse.

[SiuiS]

We have the chore that whenever we have an argument with my girlfriend - and I use a series of logical deductions to prove myself right (worth noting: I don't have to be right, just smarter ), she hits me (she's half my size, so doesn't really hurt). I take it as a cue that she surrenders the argument, so it works out for me.

Also, most of my friends have learned to agree to whatever I'm saying - since arguing eventually gets them proven wrong (again, they don't have to be wrong). That also makes people who tend to like being center of attention with needless blabbering hate me - but so be it.

So you are willing to lie and use deliberate obfuscation to hide it until people learn that trying to have a discussion isn't worth their time? That's immoral. Why would you purposefully do this? Logically, divining the truth of a situation is superior in most if not all aspects, compared to being Right and Winning. The sum total of this method is lower than if everyone worked toward a greater understanding.

[Eloel]

So, basically, you are bragging to us about how your interlocutors are poor debaters?

Basically, yes. And I like to think that my interlocutors are at worst selected randomly from the whole population, thus, the state of the world.

So you are willing to lie and use deliberate obfuscation to hide it until people learn that trying to have a discussion isn't worth their time? That's immoral. Why would you purposefully do this? Logically, divining the truth of a situation is superior in most if not all aspects, compared to being Right and Winning. The sum total of this method is lower than if everyone worked toward a greater understanding.

No, I'm willing to lie till people either improve themselves enough to understand logic, or accept themselves as inferior.
I'm not concerned with sum total, why would I be?

[ufo]

No, I'm willing to lie till people either improve themselves enough to understand logic, or accept themselves as inferior.
I'm not concerned with sum total, why would I be?

So when you mention your friends, that's hypothetically speaking?

[Talya]

Logic is, by definition, the only form of rational thought, as "logical" is a synonym of "rational." Therefore, rational thought is also logical thought.

As such, any conclusion that is illogical, is also irrational. Anyone who disputes the validity or usefulness of logic in a general sense basically has issues with reason and rationality and intellect. Any irrational means of evaluating information is, at best, erroneous, and at worst, delusional or even insane.

With that said, logic cannot provide value or weight to the various end results that it can envision. As humans, there is nothing logical in the slightest about our subjective preferences, and so two people with equal skill at using logic can come to completely different conclusions in many situations, due to differing subjective preferences or different basic premises.

[warty goblin]

Logic, at least in the mathematically pure way I tend to encounter it, is simply a calculus of sets and/or givens based on some simple axioms and definitions. Under these, logic simply produces results that must be true given some true conditions.

For almost any sort of application, a person must needs use a broader set of definitions and assumptions than is available in basic logic. These assumptions are not themselves produced by logic directly, although much of the time they are informed by how the logical calculus will process them. But they themselves are simply assumed true, and not subject to logical verification in the same way the conclusions drawn from them are. Axiomatic geometry is an excellent example of this; you can logically derive both Euclidean and hyperbolic geometry by changing a single axiom; this does not tell you anything about whether Euclidean or hyperbolic geometry is true however.

Which is why I think it a fundamental misunderstanding of what logic is to hold that it cannot say anything about ethics or morality or human subjectivity. If you start with a set of assumptions grounded in ethics, logic will produce a logical result from those assumptions. You can use logic to reason logically from your own subjective views.

I suspect the reason for this confusion is that, as Talya pointed out, logic and rationality are taken to be synonymous*. Rationality is, in modern society, often associated with a certain set of beliefs about an individual's penchant for placing the increase of their own welfare above anything else. This leads to actions often considered immoral, and, under the givens of that belief system, logical. This says nothing about the morality or immorality of logic however, as it may just as well be turned towards compassion and empathy as greed and callousness. The hammer can be used to break a man's fingers in the torture chamber, or build a newborn a crib. The first is not a universal condemnation of hammers any more than the second is a unanimous praise of them. The hammer is the tool, by its use can you know the character of the user.




*A point I would contest. Logic is a tool of rationality, just as a hammer is a tool of a carpenter. It's foolish to say a hammer and a carpenter are the same thing however. And just as many things can be made with a hammer, many rational results can be derived using logic.

[Mx.Silver]

Which is why I think it a fundamental misunderstanding of what logic is to hold that it cannot say anything about ethics or morality or human subjectivity. If you start with a set of assumptions grounded in ethics, logic will produce a logical result from those assumptions. You can use logic to reason logically from your own subjective views.

Pretty much all self-respecting schools of ethical though have to be logical. Killer Angel's implication that the only logical system is some warped form of act-consequentialism would be a slap in the face to any proponent of a deontological or virtue-based system of ethics.

[Eloel]

So when you mention your friends, that's hypothetically speaking?

Would you prefer minions?

[Killer Angel]

Pretty much all self-respecting schools of ethical though have to be logical. Killer Angel's implication that the only logical system is some warped form of act-consequentialism would be a slap in the face to any proponent of a deontological or virtue-based system of ethics.

Not exactly. I'm not saying that ethical processes and reasonings are not logical (they are), and I'm not saying that the only logical thoughts are the ones that leads to personal gain (or to a vision of the world self-centered on your own advantage).
I'm saying that, if your personal convinctions don't have ethical bases, the application of logic, will lead to inhuman results.

(so, i should say that, in truth, I'm not scared by logic itself, but by the lack of moral principles. Sadly, the consequences of moral lacking, are justified with the use of logic)

[Talya]

*A point I would contest. Logic is a tool of rationality, just as a hammer is a tool of a carpenter.

I disagree, as there are no other tools of rationality. A carpenter has many tools, and a hammer is only one of them. There is no other rational way that one can evaluate and analyze the information that is presented to them other than logic. Logic does not suffice when it comes to decision-making, because logic merely analyzes the data. The ultimate goals or purpose of the decisions that logic informs are outside the realm of rationality.

Ethics, morality, personal taste - rationality has no bearing on those things. A genocidal monster is not necessarily any more or less rational than a humanitarian philanthropist. Both can be equally informed by logic. Logic is a filter used to treat the data we receive through our other senses, by which one can be informed to make an "informed decision." What we do with that logic is a matter of subjective opinion, and logic and rationality cannot inform us of what we like best.

[Ravens_cry]

Logic is only as good as the assumptions it is based on, and all logic is based on assumptions that quite possibly can not proven in and of themselves. Garbage in garbage out, and even if you follow things quite rationally by the rules of logic, you can still get to misleading results based on said assumptions.
Still, t's a very useful tool though within its limits.

[Talya]

Logic is only as good as the assumptions it is based on, and all logic is based on assumptions that quite possibly can not proven in and of themselves. Garbage in garbage out, and even if you follow things quite rationally by the rules of logic, you can still get to misleading results based on said assumptions.
Still, t's a very useful tool though within its limits.

Agreed.

Although I'd add that, while some assumptions are required even to function, half of the problems with human society through all of recorded history have been with completely unfounded assumptions being accepted as fact, and then making logical decisions based on those assumptions.

The less we can assume, the better. The only assumptions we truly need to begin rational thought are "What we can perceive around us is real - we do not live a soliptic existence as a brain in a jar," and "The physical laws of the universe seem to be consistent." (And even the latter needs to be taken with a grain of salt.) A few basic assumptions about the necessity of a functional and organized human social structure might be good, too, but lots of people will disagree on those.

[warty goblin]

I disagree, as there are no other tools of rationality. A carpenter has many tools, and a hammer is only one of them. There is no other rational way that one can evaluate and analyze the information that is presented to them other than logic. Logic does not suffice when it comes to decision-making, because logic merely analyzes the data. The ultimate goals or purpose of the decisions that logic informs are outside the realm of rationality.

Rationality has plenty of other tools. Today for instance I'm going to code a Metropolis-Hasting step within my overall Gibbs sampler. This is an entirely rational decision; it can be justified by appeal to general practice and the fact I have no idea how else to sample from a couple of these conditionals. It is not however logical, to the best of my knowledge no proof exists that this will result in a Markov chain that converges at all, let alone to the right distribution.

Reasoning from past experience is rational, but unless you know the situation is exactly the same it cannot hope to be logical. Reasoning by analogy is a form of rational thought, but is not particularly logical.

Ethics, morality, personal taste - rationality has no bearing on those things. A genocidal monster is not necessarily any more or less rational than a humanitarian philanthropist. Both can be equally informed by logic. Logic is a filter used to treat the data we receive through our other senses, by which one can be informed to make an "informed decision." What we do with that logic is a matter of subjective opinion, and logic and rationality cannot inform us of what we like best.

Again I differ. I liked the first three seasons of Game of Thrones a lot. It is entirely rational to expect that I'll like season 4 a lot as well. It's not logical; I certainly can produce no proof about the matter, but I doubt many people would say my anticipation is irrational.

[Talya]

Rationality has plenty of other tools. Today for instance I'm going to code a Metropolis-Hasting step within my overall Gibbs sampler. This is an entirely rational decision; it can be justified by appeal to general practice and the fact I have no idea how else to sample from a couple of these conditionals. It is not however logical, to the best of my knowledge no proof exists that this will result in a Markov chain that converges at all, let alone to the right distribution.

Reasoning from past experience is rational, but unless you know the situation is exactly the same it cannot hope to be logical. Reasoning by analogy is a form of rational thought, but is not particularly logical.



Again I differ. I liked the first three seasons of Game of Thrones a lot. It is entirely rational to expect that I'll like season 4 a lot as well. It's not logical; I certainly can produce no proof about the matter, but I doubt many people would say my anticipation is irrational.

Both of your examples are examples of logical thought, though. Oh, the appeal of GoT in itself is not founded in logic (it's founded in OMFG this is awesome!), but the inference that because you liked seasons 1-3, there is some degree of probability that you will like season 4 is logical. It's a probability equation. Similarly, your coding decision is founded on logic as well - whether consciously or not. It's a cost-benefit analysis of familiarity, functionality, and simplicity, vs. the odds that learning to do it differently might improve the process. Logic is the tool you use to inform yourself of the facts you know, and the probabilities involved to fill in the blanks you don't know, before you make a choice.

[Finlam]

Ethics, morality, personal taste - rationality has no bearing on those things.

Ethics is a system fundamentally based in logic. Unless rationality suddenly has no bearing on logic, then your statement is both overly emotional and patently false.

If by 'Ethics' you meant the emotional attachment to 'right' and 'wrong' that most people use as their personal ethics, then yes, there is no room for logic because it is never applied within that ethos.

In actual ethics, however, an entirely actionable system of morality is derived from the logical implications of a few basic assumptions about reality. Individuals who think about or practice non-emotion based ethics will accept and reject the basic assumptions of a specific ethical system.

Ethics is rigorous in both its application and reliance on logic, however, and most people find it much easier to go with their 'gut instinct' or make choices based off of emotion i.e. they have never given serious thought to ethics and would much rather wing it. Saying that rationality has no bearing on ethics is like saying that rationality has no bearing on mathematics just because most people are terrible at it. That statement could not be more wrong, and that is not a matter of opinion.

[Ravens_cry]

Agreed.

Although I'd add that, while some assumptions are required even to function, half of the problems with human society through all of recorded history have been with completely unfounded assumptions being accepted as fact, and then making logical decisions based on those assumptions.

The less we can assume, the better. The only assumptions we truly need to begin rational thought are "What we can perceive around us is real - we do not live a soliptic existence as a brain in a jar," and "The physical laws of the universe seem to be consistent." (And even the latter needs to be taken with a grain of salt.) A few basic assumptions about the necessity of a functional and organized human social structure might be good, too, but lots of people will disagree on those.

The latter isn't helped by the fact we really don't know what the laws of physics, so much as we have made up lies that fit the found facts so far. As the found facts change, so do the lies. I've mentioned it before, but I think Feynman's chess analogy for science is about perfect. We are observing part of a great game, and we are trying to grok the rules of the whole by watching play.
It is a humbling yet also reassuring thought.

[Talya]

In actual ethics, however, an entirely actionable system of morality is derived from the logical implications of a few basic assumptions about reality. Individuals who think about or practice non-emotion based ethics will accept and reject the basic assumptions of a specific ethical system.

This is the problem. Those "few basic assumptions" themselves are not founded in logic. That doesn't mean we don't need them for society to function, but there's nothing logical or rational about those assumptions. They are ultimately based on, at there core, primal urges and biological imperatives. Again, there's nothing wrong with that, but they are not rational.

Furthermore, I take exception to the stated "logical derivation" of certain common ethical standards. Ethics is not a science, it's a philosophy, no more logical than any of them. Oh, it uses logic, but it is not rooted in logic. The vast majority of ethics is utter hogwash with no logical basis even on those basic assumptions. Ultimately, "Ethics" is just dressed up "morality" - they're blanked assumptions of right and wrong. What people don't understand is those assumptions are entirely personal - even at the most basic level of the philosophy. There is nothing empirical about them - they don't exist except in the human mind, and they exist differently for each and every person in the world. Ethics/Morality and every possible judgement of "right" and "wrong" are nothing more than an individual human opinion construct that is partially shared socially. That's not to say there aren't quite valid reasons for many of the more common opinions - in fact, there are quite sensible evolutionary reasons for many of them. Those reasons are not the same as the reasons people think of when they're trying to figure out why they look at something as "right" or "wrong," however.

[Asta Kask]

There are those who agree with you, and there are those who disagree. I recommend Sam Harris's the Moral Landscape.

[Talya]

There are those who agree with you, and there are those who disagree. I recommend Sam Harris's the Moral Landscape.

Interesting book. I'm having trouble getting through the introduction, when it is filled with factually inaccurate and loaded sentences like this:

In fact, all the research indicates that corporal punishment is a disastrous practice, leading to more violence and social pathology—and, perversely, to greater support for corporal punishment.

While there are competing studies on these issues, even the negative ones make assumptions that are are problematic. "Spanking makes children more aggressive!" Why is this bad? Why are we trying to build a culture of meek and peaceful hippies anyway? What if we liked the world when responding to an insult with one's fists was both legal and socially accepted - when a fistfight in school made you stay in for recess, instead of having you suspended due to "zero tolerance policies." The great irony is that in our more "primitive" social structures of previous decades, kids weren't shooting up schools with guns. The liberal peacenik love & harmony bias doesn't do us any favors.

Earlier in the same introduction he refers to the evolutionary view of morality in a dismissive way, referring to it as "apish urges." This dismisses life and evolution as somehow less than it is. We are apes. There is no wide gulf separating humans from other primates. There is no huge, substantive difference between us and the rest of nature. We have a tiny bit more reasoning ability, which has resulted in all the differences in tool use that separate us. This is not in any way an attempt on my part to denigrate humanity as "mere animals." I find the entire phrase "mere animals" insulting. There's nothing "mere" about nature. We are overly dismissive of the rest of the fauna on this planet and our origins. When I seem to suggest that we are "only" animals, I am not suggesting that we are not so lofty creatures as we assume. I'm suggesting that so are they.

Still, Sam Harris is generally on the same side of most Youtube debates that I would be, so I will try to continue reading beyond the introduction.

[Finlam]

This is the problem. Those "few basic assumptions" themselves are not founded in logic.

Logic is only as good as the assumptions it is based on, and all logic is based on assumptions that quite possibly can not proven in and of themselves. Garbage in garbage out, and even if you follow things quite rationally by the rules of logic, you can still get to misleading results based on said assumptions.
Still, t's a very useful tool though within its limits.

Agreed.

I'm not sure you understand your point.

That doesn't mean we don't need them for society to function, but there's nothing logical or rational about those assumptions. They are ultimately based on, at there core, primal urges and biological imperatives. Again, there's nothing wrong with that, but they are not rational.

This couldn't be more false. Your statement holds true only for emotion based personal ethics, not for any meaningful use of the word 'Ethics'.

Furthermore, I take exception to the stated "logical derivation" of certain common ethical standards.

I think this is both the root and sum of our disagreement. What you call 'ethics' is no more than feel good morality. I've never once mentioned that any rational system of ethics was a 'standard' or that it was 'common', rather just the opposite. Individuals that actually practice ethics are few and far between.

Ethics is not personal, it is not individual, it is a rigorous discipline that most people simply do not have the patience or desire to learn.

If you group every single ethical statement and incomplete ethical philosophy together, then yes the vast majority are hogwash. This is because you are lumping things that are not ethics in with things that are ethics. Equating moral platitudes that rarely get past "drugs are bad m'kay?" to Ethics is like equating my stove to the sun because they are both hot.

If you meant to say that personal morality is bad because it's based on instinct and emotion, then I am in full agreement with you. However, ethics as a discipline is a system of logic.

[warty goblin]

Both of your examples are examples of logical thought, though. Oh, the appeal of GoT in itself is not founded in logic (it's founded in OMFG this is awesome!), but the inference that because you liked seasons 1-3, there is some degree of probability that you will like season 4 is logical. It's a probability equation. Similarly, your coding decision is founded on logic as well - whether consciously or not. It's a cost-benefit analysis of familiarity, functionality, and simplicity, vs. the odds that learning to do it differently might improve the process. Logic is the tool you use to inform yourself of the facts you know, and the probabilities involved to fill in the blanks you don't know, before you make a choice.

Logic is a calculus of truth and falsehood. It does not do probability - I know, I study probability theory, which at the end of the day is about entirely deterministic mathematical constructs. You can build a system of booleans and equations on top of probabilities to be sure.
e.g.

• (If I liked the previous season of GoT, the probability of me liking the next season is .9)
• (If the probability of me liking something is greater than .85, I should buy it).
• (I liked the previous season of GoT)
• (Therefore I should buy the next one).

The conclusion of buy Season 4 next year follows logically, but the if - then statements that justify the result are themselves assumed without proof. Moreover the only support I can offer for them is the standard that it's worked in the past, which is entirely reasonable, but a far cry from true logic.


Cost-benefit analysis is also not logical as such. Logic has no notion of cost. You can create such a thing certainly, and logic will tell you how it must behave, but there's no logical justification for such. Again, I've done this sort of math, the cost/benefit function is explicitly arbitrary and its choice cannot be logically proven optimal. It can be reasonably justified - I can believe it's better to underestimate a variance component than overestimate, and so choose an asymmetric loss function, but the impetus to favor underestimation is not logically provable.

This is the problem. Those "few basic assumptions" themselves are not founded in logic. That doesn't mean we don't need them for society to function, but there's nothing logical or rational about those assumptions. They are ultimately based on, at there core, primal urges and biological imperatives. Again, there's nothing wrong with that, but they are not rational.

The basic assumptions of any system to which logic is applied are not themselves logical. This includes, by the way, the basic assumptions of logic itself. For instance the assumption that contradictions cannot exist is something that has to be assumed and cannot be justified by logic. This is, fascinatingly enough, a provable result. The uniqueness of parallel lines must also be assumed and cannot be proven; a statement which again has been proven.

Furthermore, I take exception to the stated "logical derivation" of certain common ethical standards. Ethics is not a science, it's a philosophy, no more logical than any of them. Oh, it uses logic, but it is not rooted in logic. The vast majority of ethics is utter hogwash with no logical basis even on those basic assumptions. Ultimately, "Ethics" is just dressed up "morality" - they're blanked assumptions of right and wrong. What people don't understand is those assumptions are entirely personal - even at the most basic level of the philosophy. There is nothing empirical about them - they don't exist except in the human mind, and they exist differently for each and every person in the world. Ethics/Morality and every possible judgement of "right" and "wrong" are nothing more than an individual human opinion construct that is partially shared socially. That's not to say there aren't quite valid reasons for many of the more common opinions - in fact, there are quite sensible evolutionary reasons for many of them. Those reasons are not the same as the reasons people think of when they're trying to figure out why they look at something as "right" or "wrong," however.

You're arguing a double standard. There's nothing particularly empirical about my liking Game of Thrones, yet you claim the choice to buy the next season is logical. There's nothing particularly empirical about thinking cannibalism is wrong, yet the same reasoning would suggest it must therefore be logical to state that one should not grill up the neighbors with a nice BBQ sauce.

Actually I think there's a good bit more empirical about stating cannibalism is wrong, since it can be empirically verified as a common (not universal) human belief. I think it also is entirely logical to state that if cannibalism is wrong, BBQing Mr. and Ms. Nextdoor is wrong, since that would, in fact, be an act of cannibalism.

[Asta Kask]

If you meant to say that personal morality is bad because it's based on instinct and emotion, then I am in full agreement with you. However, ethics as a discipline is a system of logic.

Even if it is, you must still get your premises from somewhere. You can get them from an analysis of human nature, from a book, from a philosophy or from somewhere else entirely, but you can't get it from logic.

For instance, Sam Harris takes it as his starting point that morality is about the suffering and well-being of conscious creatures. And he claims to those who disagree are simply wrong on linguistic grounds - they have not understood what the word means. Now, this may or may not be true (I think it's a rather weak argument), but it can certainly be questioned. It is not self-evident, except apparently to Sam Harris. And while you can justify some premises all of the time, and all of the premises some of the time, you can't justify all of them all of the time (because this leads to an infinite regression).

[Talya]

If you meant to say that personal morality is bad because it's based on instinct and emotion, then I am in full agreement with you.

I am not in agreement with this. Oh, i agree that personal morality is based on instinct and emotion. Nowhere have I stated that instinct and emotion are "bad." Instinct and emotion are a major part of of what has gotten us to where we are today at the top of Earth's evolutionary ladder.

There's this assumption that anything not derived from logic or rationality is inferior. There are a good many instinctual/emotional responses that are essential to our survival that have no basis in logic or rationality at all.

I also believe, however, that "ethical philosophy" is just a complex house of cards built, partially through logic, yes, but on a foundation that is still entirely subjective and irrational. It's a pseudo-discipline that has no more validity as a guide to human behavior than any other means at our disposal.

[Asta Kask]

By what standard do you measure validity? What do you mean by it?

[Talya]

By what standard do you measure validity? What do you mean by it?

I believe by "no more validity" I mean to say that it is no more and no less empirically "right" or "wrong". It cannot be tested, it cannot be falsified. We don't even have an empirical means by which to evaluate the results, even if we could know them precisely. It's simply another human construct of behavior.

Logic is a calculus of truth and falsehood. It does not do probability - I know, I study probability theory, which at the end of the day is about entirely deterministic mathematical constructs. You can build a system of booleans and equations on top of probabilities to be sure.
e.g.

• (If I liked the previous season of GoT, the probability of me liking the next season is .9)
• (If the probability of me liking something is greater than .85, I should buy it).
• (I liked the previous season of GoT)
• (Therefore I should buy the next one).

The conclusion of buy Season 4 next year follows logically, but the if - then statements that justify the result are themselves assumed without proof. Moreover the only support I can offer for them is the standard that it's worked in the past, which is entirely reasonable, but a far cry from true logic.


Cost-benefit analysis is also not logical as such. Logic has no notion of cost. You can create such a thing certainly, and logic will tell you how it must behave, but there's no logical justification for such. Again, I've done this sort of math, the cost/benefit function is explicitly arbitrary and its choice cannot be logically proven optimal. It can be reasonably justified - I can believe it's better to underestimate a variance component than overestimate, and so choose an asymmetric loss function, but the impetus to favor underestimation is not logically provable.

Those things are entirely logical. Mathematics is entirely logical -- mathematics is the language of logic. Quantum Physics, for example, is entirely logical (albeit counterintuitive to us macro-beings in many cases), and almost entirely based on probabilities. Logic most certainly has a notion of cost. This can be as simple as calculating the cost in energy to counter the momentum of a moving object.

The basic assumptions of any system to which logic is applied are not themselves logical. This includes, by the way, the basic assumptions of logic itself. For instance the assumption that contradictions cannot exist is something that has to be assumed and cannot be justified by logic. This is, fascinatingly enough, a provable result. The uniqueness of parallel lines must also be assumed and cannot be proven; a statement which again has been proven.

These are mathematics problems, and are therefore by definition logical. It is entirely logical to make an assumption that can be tested, and repeatedly found to hold true. We cannot prove that assumption, but it is logical to hold it as fact until such time as it is contradicted.

Also, the assumption that contradictions cannot coexist has already been disproven (quantum physics.) However, thus far, we've failed to find evidence of such contradictions at the macro level.

You're arguing a double standard. There's nothing particularly empirical about my liking Game of Thrones, yet you claim the choice to buy the next season is logical.

Watching something you like is logical. There is no empirical logic that dictates what you will like, but choosing to watch something you enjoy (a benefit) is entirely logical, while watching something you do not enjoy and gain nothing from is not logical. What is logical is determining a probability that you will like season 4 based on the fact that you liked seasons 1-3. Like all probabilities, you can end up on the outlier (season 4 may suck!), but the decision to watch it is logical.

There's nothing particularly empirical about thinking cannibalism is wrong, yet the same reasoning would suggest it must therefore be logical to state that one should not grill up the neighbors with a nice BBQ sauce.

There is nothing logical about the underlying assumption that cannibalism is wrong. (Or, there may be logic behind that assumption, but ultimately that logic leads back to assumptions with bases that are not logical.) However, there are several other logical reasons behind the decision not to grill up the neighbors with bbq sauce. (EG. "I like the neighbors. If I eat them, they will be dead and I can no longer enjoy their neighborliness." "I like my freedom. I do not wish to go to prison, so I will refrain from murdering.") As I have already stated, EVERY decision has, if you go far enough down the chain, a basis that is not rooted in logic. We simply cannot make decisions based on rationality or logic alone. Even the decision to eat food relies on the desire to not be hungry/continue living, which has no logical/rational basis.

Actually I think there's a good bit more empirical about stating cannibalism is wrong, since it can be empirically verified as a common (not universal) human belief. I think it also is entirely logical to state that if cannibalism is wrong, BBQing Mr. and Ms. Nextdoor is wrong, since that would, in fact, be an act of cannibalism.

Technically, eating them would be the act of cannibalism. Cooking them is something else. Again, commonality of belief has nothing to do with rationality or empirical evidence. It simply indicates some evolutionary reason for us to be endowed with such a sentiment.

There's not even anything empirically wrong with murder. We have laws against it, we have personal morality that keeps us from doing it, but it's not a universal truth that can be evaluated and stated as fact. All our rules - both in the form of societal law and personal morality - are ultimately built from the pressure of evolutionary instincts and natural selection.

[Asta Kask]

I believe by "no more validity" I mean to say that it is no more and no less empirically "right" or "wrong". It cannot be tested, it cannot be falsified. We don't even have an empirical means by which to evaluate the results, even if we could know them precisely. It's simply another human construct of behavior.

Good. Now, I admit that the choice of values does not depend on empirical facts, but different systems may not be equally efficient at promoting a given value. For instance, if we put "health" as a value then a system from the 18th century will probably not be as useful in promoting health as a system from 2010. So the choice between them is not entirely arbitrary - do you agree?