> To call an argument "valid" is to make a normative claim; it is to claim that a rational agent ought to accept it.
Idk, it could just be a claim that the argument can be expressed in a logical system, combined with the normative axiom that rational agents should only trust arguments that can be validly expressed in such a formal system.
Regardless this seems to be missing the forest for the trees. Nobody has put forth any arguments for either position that are emperical in nature. Is there really a practical difference between impossible and possible but nobody knows how?
The term "valid" has both formal and informal senses. I agree some of its formal senses are non-normative, but I think its informal uses have a strong normative element. The original comment to which I was responding wasn't very clear about in what sense it was intending the term, but when people aren't clear, it is not unfair to assume they mean a term informally rather than in some specific formal sense.
> Regardless this seems to be missing the forest for the trees. Nobody has put forth any arguments for either position that are emperical in nature. Is there really a practical difference between impossible and possible but nobody knows how?
What is the proper role of empiricism in human knowledge, including moral knowledge? You seem to be making some assumptions here which you are not making explicit.
If one accepts moral sense theory – that moral intuitions are a form of empirical knowledge – then we can have direct empirical knowledge of the truth or falsehood of moral propositions.
If one accepts pragmatism – that beliefs can be justified by the pragmatic benefits of believing them, and that pragmatically justified beliefs can constitute genuine cases of knowledge – then empirical evidence can be used to establish the pragmatic benefits of a moral belief, and hence (indirectly) to establish its truth.
One may believe that some axioms are self-evidently true, and that one's knowledge of the truth of those axioms is innate rather than empirical – in which case, if one accepts that for non-moral axioms, how about accepting it for moral axioms as well?
You can argue that one will lead to a preferable world than the other.
Of course, we may have different preferences, so we may not agree even if we agree on that extrapolation. But often basic human preferences like not wanting to be the victim of unprovoked public violence do align.
Example of application: Consider "It is always immoral to have children". Obviously, if humanity universally obeyed that principle, human extinction would inevitably and quickly follow. Therefore, that principle is false. From which obviously follows: "It is moral to have children (at least sometimes)".
Now, I would propose we accept that meta-moral principle as an axiom. To me, and to many others, it seems self-evidently and intuitively true. Who seriously doubts or denies this axiom? Well, most of the people who doubt or deny it, do so not due to its specific content, but due to a philosophical objection to accepting any moral axioms at all. The number of people who are happy to accept moral axioms but would refuse to accept this particular one appears to be rather small. It seems as good a candidate to be an axiom as any other. So why not accept it as an axiom?
Initially I claimed, “There are no valid arguments for normative claims.”, I would like to amend my claim.
Def: An inferential system is a tuple of axioms and inferential rules.
Def: An argument is a non-empty ordered sequence of statements. The last statement is called its conclusion.
Claim: If an inferential system produces an argument for a normative claim, the system is either inconsistent or permits inference from positive statements to normative statements or the argument proceeds from normative axioms.
Proof. Suppose S is a consistent inferential system and that A is an argument in S from S’s axioms to a normative conclusion. If S has only positive axioms then A makes inference from positive to normative statements. QED
Corollary: There are no arguments for normative claims that don’t proceed from normative axioms in consistent systems that don’t permit inference from normative to positive statements.
I agree with you there. But you haven't explained how this (obviously true) statement is relevant to the original discussion, about the morality of providing life-saving medical treatment to perpetrators of serious crimes.
My original point was in response to the claim that “the key principle in medicine is to treat anyone who is sick, regardless of who they are”. I took this to be an ought and wanted to point out that its truth isn’t established anymore than the ought indicated by Ed’s family, and that in fact there would be serious difficulties with establishing either one for the reason given by your last post:
> a valid deductive argument with a normative conclusion must either have a normative premise, or else rely on a logic whose inference rules permit normative statements to be inferred from non-normative ones.
But also I think that this poster makes a good point that the doctors are actually making a positive claim.
https://news.ycombinator.com/item?id=30081152
> To call an argument "valid" is to make a normative claim; it is to claim that a rational agent ought to accept it.
I think I had in mind a textbook definition I had read.
An argument is called valid if it is impossible for the premises to be true and the conclusion false. And then we say that an argument is sound if it is both valid and has true premises.
Which seems like a useful pair of definitions, and in that context I was confused about the terms.
I actually haven’t ever thought about or heard of this idea of ‘when is a rational actor committed to accepting claims’. But yeah, seems interesting to me.
I think your overall point is, you are expressing scepticism about claims to know the truth of some particular moral proposition, grounded in a more general scepticism of the possibility of any moral knowledge at all.
I think that kind of general moral scepticism is (usually) a form of normative scepticism. The big problem I see with normative scepticism, is that attempts to argue for it logically and rationally turn out to be self-refuting, because logic and rationality are themselves normative concepts. Furthermore, if one understands knowledge as having a normative component, normative scepticism collapses into radical scepticism (there is no such thing as knowledge), which obviously ought to be rejected.
I don’t have any sense for the various properties of inductive arguments. So to the extent that moral arguments are inductive, I have nothing to say. Thanks for pointing out that I’m assuming moral arguments must be deductive. Any recommendations for an introductory text on inductive arguments?
> That’s why I read your statement as intending “valid” informally rather than formally, since in its informal sense the term is not restricted to purely deductive arguments; and informally it is very much a normative concept (formally, I think it has multiple formal senses, some of which contain more normativity than others)
Understood.
> I think your overall point is, you are expressing scepticism about claims to know the truth of some particular moral proposition, grounded in a more general scepticism of the possibility of any moral knowledge at all.
Yes, that is my point.
> I think that kind of general moral scepticism is (usually) a form of normative scepticism. The big problem I see with normative scepticism, is that attempts to argue for it logically and rationally turn out to be self-refuting, because logic and rationality are themselves normative concepts.
This is the first time that I’ve heard of normative epistemology, which I gather is what you are talking about. One thing I will say though, thinking about this seems smoother than thinking about normative morality because (I think) I don’t have as many childhood memories of people telling me what I ought to think compared to those of people telling me what I ought to do.
You can easily find a lot of resources on this topic, but I can't think of any to particularly recommend. To give my own high-level summary, there are three main types of logical arguments:
- Deductive arguments: from the premises, the conclusion necessarily follows. If the premises are true, and the argument is valid, the conclusion must be true. These are the kinds of arguments found in mathematical proofs, and classical syllogisms such as "All men are mortal, Socrates is a man, therefore Socrates is mortal"
- Inductive arguments: from many particulars, infer a generalisation. If all swans so far have been observed to be white, it is reasonable to conclude that "All swans are white" – and the more observations you make, the stronger the conclusion becomes – but that conclusion can never be certain, only probable, because maybe tomorrow someone will discover a black swan, proving the conclusion to be false after all–which is of course what actually happened, when Europeans came to Australia and found swans which were black. (Also, confusingly, "mathematical induction" is a type of deductive argument, not induction in the logical sense.)
- Abductive arguments: from a situation, infer the truth of its most plausible explanation: If I walk into a room and find toys spread all over the floor, I am going to conclude that our four year old did it. Now, maybe some crazy stranger broke into our house, threw toys everywhere, then left – not absolutely impossible, but far less likely than it being our four year old.
The big difference: in deductive arguments, if the argument is good, and the premises are true, the conclusion must be true; in non-deductive arguments, the argument can be good, and the premises can be completely true, and yet the conclusion can still be false. A deductive argument which produces a false conclusion from true premises is by definition a bad one; a non-deductive argument which produces a false conclusion from true premises can still be a perfectly good one, provided that unfortunate outcome is improbable.
The natural sciences use all three, but rely heavily on induction and abduction. Historians primarily use abduction – induction works best for repeatable events, whereas many of the events historians study are essentially unique and unrepeatable (World War II was in many ways a unique event in human history, nothing quite like it had ever happened before, even World War I was different in many ways, and if World War III ever happens it is going to be very different again).
I think a lot of moral reasoning must be non-deductive, because deductive arguments generally deal with certainties, whereas it is quite natural for people to say about moral issues "I think it is probably wrong but I'm not 100% sure". I think moral reasoning often involves some degree of induction – if you repeatedly encounter particular situations which offend your conscience, you are likely to adopt a moral principle which condemns whatever those particular situations have in common – generalising a principle out of particular cases, which is essentially what inductive reasoning is. But, as in all inductive reasoning, you can never be sure that there will not be some case which might convince you that your generalisation needs an exception – a moral black swan.
> This is the first time that I’ve heard of normative epistemology, which I gather is what you are talking about.
Yes, exactly. A lot of the concepts traditionally used in epistemology appear to be normative. For example, in the classical definition of knowledge as "justified true belief", justification appears to be a normative concept – a belief which is justified given some evidence is a belief which one ought to hold (or, at least, one is permitted to hold) given that evidence, a belief which is unjustified given some evidence is a belief which one ought not to hold given that evidence.
> One thing I will say though, thinking about this seems smoother than thinking about normative morality because (I think) I don’t have as many childhood memories of people telling me what I ought to think compared to those of people telling me what I ought to do.
I think a lot of people grow up exposed to conservative religious approaches to morality, which they often experienced as being pushed on them inflexibly and never with any convincing justification–and it is unsurprising many such people become attracted to the idea that "morality is subjective". However, I wonder, is that "throwing the baby out with the bathwater"? Most of these people would feel strongly that genocide, slavery, apartheid, torture, child abuse, theocratic totalitarianism, etc, are immoral – yet, having accepted "morality is subjective", those moral positions they endorse must be just as subjective as those which they've rejected. Subjective morality weakens their own moral positions. Indeed, once you believe that morality is subjective, you can no longer claim (in any objective sense) that anyone else's morality is wrong, including that of various religious conservatives – the most you can consistently say about their morality is that you don't like it – but why should they (or anyone else) care about what you like?
Can you offer a valid argument for the truth of your own principle, that it is impossible to offer a valid argument for the truth of any normative principle? I think your own position is a normative principle, and hence your position is self-refuting.
To call an argument "valid" is to make a normative claim; it is to claim that a rational agent ought to accept it. To call an argument invalid is to claim that a rational agent ought not accept it. Rationality has as much oughtness as morality does, and hence is a normative discipline just as morality is.