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So you believe once you're aware of your own existence nothing else follows?

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bd-from-kg :

It's a claim about claims about the real world? Well, it's basically a claim about how we should interpret the real world, so I think there's a pretty direct relationship between this claim and the real world.

Well first you have to assume Sagan's assertion is true. Then you apply your assumption to all possible worlds. Seems like a non-sequitur.

This is your interpretation of the quote, but the actual assertion in question: "Claims that cannot be tested, assertions immune to disproof are veriditically worthless" - has no mention of evidence at all. He mentions evidence later but the assertion itself is devoid of the concept of evidence. In fact, I can think of a few cases where evidence is irrelevant:

A) Evidence can be found, but the claim is untestable due to lack of repetition: Ie. the big bang

Are claims of this nature "veriditically worthless"? How can you possibly prove it?

B) No evidence is found, but the claim is an objective truth. Ie. Human life is valuable.

How can you prove this wrong? It is an assertion immune to disproof. Is it veridically worthless?

bd-from-kg

Normal:

Of course there is, or it wouldn’t be of any interest. But the relationship is not that it’s a claim about the real world.

As I explain below, on reconsideration it’s not clear just what Sagan is asserting here, so I’m not going to talk about whether it’s “true”. But in any case it’s not a claim about the real world. And therefore it cannot be tested; it cannot be proved or disproved. After all, what is a test in this context? It has to consist ultimately of observing that something is or is not true of the real world. [Note: I include everything that exists, including supernatural entities if there are any, in the “real world”.] But any such observation can only tell us something about which of the possible worlds we live in. And the essential nature of the statement is such that either it’s true in all possible worlds or it’s false in all possible worlds. So no information about which possible world we live in has any bearing on whether it’s true.

You may have a point; this might not be the meaning Sagan had in mind. Earlier he says, “If there's ... no conceivable experiment that would count against it, what does it mean to say that my dragon exists?” The suggestion here is that a statement that cannot be tested is meaningless, in which case the question of whether to believe it doesn’t even arise. Based on this, Sagan seems to be espousing the doctrine of verificationism, which is highly controversial. But he soon continues, “What I'm asking you to do comes down to believing, in the absence of evidence, on my say-so.” Based on this he seems to be expounding the principle that I stated: that it’s irrational to believe something about the real world without evidence. As I commented earlier, this is a fundamental principle of rationality. You cannot reject it without embracing madness.

I guess your point is that one cannot perform an experiment to see whether it happens again. If Sagan were saying that all such claims are "veriditically worthless" he'd be talking nonsense. All claims about what ahppened in the past have this property. Thus, if I claim that the temperature in my back yard reached 90 degrees yesterday, my claim is untestable due to lack of repetition. Since Sagan was a pretty smart cookie, we can safely assume that he didn't mean anything so ridiculous.

But obviously one can imagine evidence that would tend to support the hypothesis and other evidence that would tell against it. This is all that Sagan means by "proof" and "disproof". There's no such thing as absolute proof or disproof in science.

Another easy one. “Human life is valuable” is not an objective truth. Of course I can’t prove it right or wrong because it isn’t right or wrong. It’s immune to disproof in the same way that “Close the door” or “Whoops!” are immune to disproof: these statements do not express propositions. And yes, they’re “veridically worthless” on any reasonable interpretation of what this means.

Clutch

Modulo some ambiguity about what "veridically worthless" amounts to, Sagan's generalization seems eminently open to disproof.

See how many examples can be produced of untestable claims having genuine explanatory or predictive utility (at least a plausible interpretation of "veridical worth"). If you can produce a bagful, then Sagan's claim is undermined.

Or, compare systems of thought or intellectual endeavours, purporting to deliver truths, divided into those that crucially invoke untestable claims and those that do not. Assess the explanatory and predictive successes of the two approaches. If an approach that freely offers untestable claims as explanations also produces correct predictions -- even when counterintuitive -- well, then Sagan's just wrong.

And by the way: 'I think therefore I am' is not, and was never intended as, an explanatory or predictive insight. The insight was supposed to be that this inference must be correct on any occasion of my rehearsing it. And as a universal generalization, that insight is certainly testable by the offering of counterexamples.

Clutch

bd,
I believe that, among the denizens of the real world, are things like sentences, investigations, theories, explanations, predictions, successes, failures, and so forth. Because I believe this, I don't understand your remarks here.

Were there a class of research programmes that explicitly helped themselves to untestable claims in crucial explanatory roles, and were these programmes forever issuing in predictions such that, acting on them, we consistently shot planetary landers past their target planets, produced alleged medicines that were deadly poisons, and never found consilient agreement of outcomes with other, apparently unrelated, disciplines... then we might well formulate Sagan's claim as an empirical explanation for the unfecundity of this class.

It's hard to see why we should even be tempted to say that such an explanation is not be "about the real world".

The fact that it's a meta-level claim about methodology hardly makes it about something other than the real world. Science is part of the real world, in my rather unrevolutionary estimation, as are things like results. In talking about how to do science to get the best results, one talks about the real world.

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bd-from-kg:

While I agree with what you said otherwise, "Human life is valuable" is different then "Close the door" and "Whoops" in that it is an assertion of truth; not only that but it is also immune to disproof. The worth of it's veracity can be seen in the structure of society, and the desire for protection of human life.

Clutch

Cripes, you guys just love branding this and that "immune to disproof". Any chance of getting arguments to this effect?

What do you mean by "valuable"?

Normally the term just means something like, "valued by at least some people". That is, surely it's correct that gold is valuable, even though there's no shortage of people who do not value gold.

In that sense, "Human life is valuable" is certainly open to evidence and counter-evidence: look for people who value human life.

If you had some other notion of value in mind, you must explain it clearly. It would hardly be an interesting development if your version of the statement was "immune to disproof" simply by being ill-defined.

Normal

You are right if veridical and predictive were synonyms, which, unfortunately for you, they are not. Veridical has more to do with truth and influence on the future then actual predictive qualities. "I think therefore I am" has truth and has influence on the future (in terms of rational thought, being aware of existence), so I fail to see how your point about predictiveness is valid at all.

bd-from-kg

Normal:

At this point we're getting into stuff that belongs in the Morality forum. Here I'll content myself with a couple of comments.

(1) "Human life is valuable" could be interpreted as meaning something like "Most humans value their lives" or even "Most humans value the lives of all humans". In either case it's clearly a meaningful statement, and eminently testable. But this isn't usually the intended meaning. It usually means something like "Human life has intrinsic value". When it's used in this sense it's meaningless because there is no such thing as "intrinsic value"; the very concept is logically incoherent.

(2) You're contradicting yourself. You say that "Human life is valuable" is immune to disproof; then you immediately cite supposed evidence in its favor. Presumably, then, if the opposite state of affairs obtained this would be evidence against it. (Otherwise in what sense is it evidence - i.e., how does it tend to support the statement?) But a statement for which it is possible to imagine evidence against it is by definition not "immune to disproof".

Normal

The point is not that it is true or that it is not true. The point is it is immune to disproof. How could you possibly go about proving human life lacks value? You could present a case, maybe, but it is quite immune to any reasonable sense of proof/disproof.

It is almost analogous to the "God/No God" debate, except “Human life is valuable” has definite veridical worth.