Be a good little atheist...

[Piscivore]

Exactly. Sometimes it really is red. Sometimes it really is yellow. The color is not whatever someone says it is. It is the result of the interaction of a number of things all of which really happen and really do produce the result that the sky is sometimes really blue.

The implications are that it is not an inherent property of the sky. You won't find some 'blueness' itself in the physical nature of sky. That we assess it as blue results from an interaction between properties of the sky, properties of us, properties of the lighting conditions, and so on. All of this results in the objective result that under certain conditions, to people with normal vision, the sky really does appear blue for reasons that are comprehensible and objective.

That's precisely correct. There is no "green" essence in grass just as there is no "evil" essence in torturing children for pleasure itself. These are emergent properties, not inherent ones.

There probably is no such thing. As I said, morality is not an inherent property but an emergent one, just as "appears blue" is. There is no object that will appear blue or "really be blue" under all circumstances.To make it always true, you have to make it non-universal. For example, "to a person with normal vision, the sky always appears blue on a sunny day unless there's dust in the sky or ..."

You've just introduced subjectivity. What is "normal vision"?

It usually does, you simply pick one thing that it does not make objective and claim that therefore it makes nothing objective.

I didn't say "nothing was objective". Gravity is objective. The speed of light is objective. I said this one thing is not, because it is possible and indeed evident that "moral values" depend on the observer.

With near certainty, we can say that something accounts for the fact that Elvis has a fan base that exceeds the fan bases of most other musicians and that his fans are particularly dedicated. With some investigation, we can surmise that a significant factor has to do with his music, but certainly other things are objectively involved factors as well. These include social factors about the time he was performing, and many other things.

Yes, 10,000 Elivis fans doesn't make "Elvis was the greatest performer of all time" objectively true. But it would be an idiot who would assume that there aren't important objective factors that account for Elvis' popularity.

No one said otherwise. But "involving objective factors" =/= "objective". If the value of or a judgment about depends on an obsever, it is not objective, no matter how many objective factors are involved.

Of course. That doesn't mean it *is* okay for them to do so. Nor does it mean it isn't okay.

Right. It depends on the observer. It's subjective.

I don't dismiss them all as broken because they are evaluating objectively different things in objectively different circumstances.

However, if you are right next to me, I see the sky is blue and the grass is green, and you swear they look the same color to you, all I can do is say that you are either broken or lying.

Your mistakes here are 1) assuming that all humans percieve things the way you do, 2) that your perceptual apparatus is "normal", and 3) "Normal" is somehow superior. What makes your perception "normal" and the colourblind guy's not?

It would be most irrational of me to conclude immediately that the color of things must be subjective and have nothing to do with the things.

That condradicts what you were saying about colour not being an inherent property, but an "emergent" one.

That would leave me unable to explain the agreement on color, the ability of people to pick things based on color, and so on.

Not at all. Regardless of perceptual differences, cultural assimilation explains the first, and it only requires some degree of visual difference be present in order to distingush one from another. Neither requires that perceptions agree.

Besides, the very existence of colourblindness (and regular old blindness) renders both moot- there isn't "agreement on colour", and some people cannot "pick things based on colour"... it depends on the observer.

Stepping out of the metaphor, you and I may agree that "torturing children" is wrong", but I may feel that way because I fear reprisal from relatives (or even the child itself when it is grown and I am old), while you have an emotional, empatheic reaction to the idea. Different perceptions, different resopnses, different perspectives... similar judgement. So while it may look objective, on closer examination it can be seen to be purely subjective.

Then why is there widespread agreement in the United States that torturing children for pleasure is worse than feeding a hungry person? How do you explain it?

Cultural assimilation, common histories, respect for (or fear of) dominant social groups, and other emotional factors. Lots of factors. You're falling for the fallacy of the single cause speculating that there is some inherent "factor" in humans responsible for this judgement.

The only rational explanation is that something objective about how people are constructed, how our society is constructed, how we are constructed, the nature of feeding hungry people and the nature of torturing children for pleasure causes us to detect one as good and one as evil as with grass and sky we detect one as green and the other as blue.

That's not rational at all. It's fallacious.

"How people are constructed" did not prove a hinderance to the Aztecs:
"The ’Atlcahualo’ was celebrated from the 12th of February until the 3rd of March. Dedicated to the Tlaloque, this veintena involved the sacrifice of many children on sacred mountaintops. The children were beautifully adorned, dressed in the style of Tlaloc and the Tlaloque. On litters strewn with flowers and feathers; surrounded by dancers, they were transported to a shrine and their hearts would be pulled out by priests. If, on the way to the shrine, these children cried their tears were viewed as signs of imminent and abundant rains. Children who did not weep could have their fingernails torn off in order to achieve this effect. Every Atlcahualo festival, seven children were sacrificed in and around Lake Texcoco in the Aztec capital. They were either slaves or the second born children of nobles."

People are not "constructed" to "detect" hurting children as "evil".

As for "how our society is constructed"- that is largely by accident, it was never "constructed", anymore than a pile of detrius washed ashore is "constructed". Take a quick peek at our Nambla or CPS records, and tell me again how child abuse is universally seen as "evil".

I'm not sure why you chose to distinguish "how we are constructed" from "people" or "society" (which is just people)... is this "we" you speak of someone other than people?

As for "nature of feeding hungry people and the nature of torturing children for pleasure"- why don't you explian what those "natures" are?

Nonsense. That would make height subjective. That would make sky color subjective.

Measurement of height is objective. Six feet is six feet. Judgments about height are subjective. To a little person, six feet is tall. To Shaq or Michael Jordan... not so much. You've already shown us how sky colour is subjective.

We don't really know yet... The best I can do is make speculations ... Future science may have more to say about this.

So you are presenting your speculations as fact? You're asserting that judgements about "torturing children for pleasure" must be objective because you speculate there are "objective properties of torturing children for pleasure" that you feel "certain" science will discover someday?

Dude, there's like three different fallacies at work there. This isn't "reason" at all.

So it's certainly possible that a better understanding of morality could lead to at least some changes in how we understand right and wrong. Nevertheless, of course, the properties of normal human color vision are also objective facts about reality, so to would be such properties about morality.

Speculation, "possiblity" and assumption is all you've got, then? Do you have even one acutal, testable, scientific fact to support these assertions?

 

[Piscivore]

As I said previously, I suspect we don't have enough of a common reasoning base to have this discussion. I'd be interested to hear what you mean by "assumption" though.

If it doesn't refer to "blessing" a conclusion as immune from doubt and it doesn't mean divorcing a conclusion from the evidence that justifies it, what's left?

Here are a number of definitions of the word "assumption", none of which agree with what you posted.
http://dictionary.reference.com/browse/assumption
"1. something taken for granted; a supposition: a correct assumption.
2. the act of taking for granted or supposing. "

http://www.merriam-webster.com/dictionary/assumption
"5 a : an assuming that something is true
b : a fact or statement (as a proposition, axiom, postulate, or notion) taken for granted"

http://encarta.msn.com/dictionary_1861587326/assumption.html
"1. something taken for granted: something that is believed to be true without proof
2. belief without proof: the belief that something is true without having any proof"

http://www.dictionary.net/assumption
2. The act of taking for granted, or supposing a thing without proof; supposition; unwarrantable claim. [1913 Webster]
3. The thing supposed; a postulate, or proposition assumed; a supposition. [1913 Webster]

And, from the same source, the actual "the logic definition":
"4. (Logic) The minor or second proposition in a categorical syllogism. [1913 Webster]"

Is English your first language?

 

[JoelKatz]

For the record, what I mean by an assumption is something we regard as true despite the recognition that we do not have complete and perfect knowledge of the facts leading up to, or the consequences which will follow, any of our decisions. Each of those decisions rests on a cascade of assumptions, which we have acquired over a lifetime of learning and experience.

I would say this is a very silly definition and looks like one carefully crafted specifically to win a debate at the expense of not saying anything. (Like things like: "You don't believe in God? But God is everything. You don't believe in everything?")

No rational or sane person would ever say that anything remotely resembling "complete and perfect knowledge" is ever needed to justify regarding something as true. So this definition effectively makes all knowledge an "assumption", except for the extremely narrow set of facts conclusively known beyond conceivable question such as "I exist". (In fact, that may be the only thing we know that's not an "assumption" under this definition.)

 

[JoelKatz]

All of these definitions are either covered by the ones I gave, trivially subject to the same analysis as the ones I gave (and thus not in need of distinction) or not relevant to the discussion.

Here are a number of definitions of the word "assumption", none of which agree with what you posted.
http://dictionary.reference.com/browse/assumption
"1. something taken for granted; a supposition: a correct assumption.

These are really all circular and not illuminating. For example, do we take something for granted because we have overwhelming evidence to justify doing so? Or do we take something for granted by not requiring evidence to accept it?

"Supposition" also has many meanings and the most common one is the one that I explained above was a meaning of "assumption" but clearly not relevant -- something we conditionally accept for reasoning knowing that it makes our conclusions conditional on its truth.

2. the act of taking for granted or supposing.

Same thing. Taking for granted is trivially equivalent to divorcing from justification or "blessing". When we "take something for granted" we exempt it from further skepticism, even if that skepticism is later justified.

http://www.merriam-webster.com/dictionary/assumption
"5 a : an assuming that something is true

Again, too vague. Do we do it because evidence justifies it? If so, how is that "assuming"?

b : a fact or statement (as a proposition, axiom, postulate, or notion) taken for granted"

That either means divorced from its justification or "blessed" by being exempted from further skepticism. These are the definitions I was talking about.

http://encarta.msn.com/dictionary_1861587326/assumption.html
"1. something taken for granted: something that is believed to be true without proof

And, of course, this is even worse than the ones I suggested. Clearly my position would be that believing something to be true without proof is error.

2. belief without proof: the belief that something is true without having any proof"

Same thing. These are even worse than my definitions. It is even worse to do these things than to "bless" or divorce from justification. At least in these cases, the assumption was justified in being considered true at some time. These are worse errors, accepting as true things never justified.

http://www.dictionary.net/assumption
2. The act of taking for granted, or supposing a thing without proof; supposition; unwarrantable claim. [1913 Webster]
3. The thing supposed; a postulate, or proposition assumed; a supposition. [1913 Webster]

The first one of these I covered above. The second is too vague to pin down. It can mean the thing I already said is perfectly okay (assuming something is true to see what conclusions it leads to fully remembering that one's conclusions are conditional) but it can also mean that we accept it as true without proof.

And, from the same source, the actual "the logic definition":
"4. (Logic) The minor or second proposition in a categorical syllogism. [1913 Webster]"

That's not relevant here.

Is English your first language?

Yes.

I think the only thing you added that I may actually have missed is "assumption" meaning to accept as true and exempt from any skepticism even though there was *never* any evidence to justify accepting the thing assumed. Obviously, I don't think this is ever justified and I think it is always error. (I mostly left this out because it is obviously the case where my argument is so strong that it barely needs to be made. This is obviously bad. This is flipping a coin to decide what to believe.)

 

[Beth]

I would say this is a very silly definition and looks like one carefully crafted specifically to win a debate at the expense of not saying anything.

No. It looks like a very commonly used definition of 'assumption'. It's what I mean by the term.

No rational or sane person would ever say that anything remotely resembling "complete and perfect knowledge" is ever needed to justify regarding something as true. So this definition effectively makes all knowledge an "assumption", except for the extremely narrow set of facts conclusively known beyond conceivable question such as "I exist". (In fact, that may be the only thing we know that's not an "assumption" under this definition.)

You might find this book review (and presumably the book) interesting: Being Wrong: Adventures in the Margins of Error by Kathryn Shultz
http://scienceblogs.com/webeasties/2011/01/how_being_wrong_can_be_so_righ.php

The reviewer says "I was a bit put off by the characterization of all forms of knowledge as "belief," but that's probably based on my proximity to the gnu atheist arguments. She makes a compelling case, and also acknowledges that some forms of evidence are more reliable than others. In the end, the argument is that ALL beliefs are subject to bias, misrepresentation and error, and I think this is a point well worth making."

I agree with the argument that all knowledge is belief. I disagree that the only conclusively known fact is 'I exist'. I think that mathematics can make statements that are conclusively facts. Of course, mathematics can only do this because it is a formal system that specifies all assumptions up front.

eta: Well, nearly all knowledge. Mathematics can be classified as knowledge and can be conclusively known as 'true'.

 

[Piscivore]

All of these definitions are either covered by the ones I gave, trivially subject to the same analysis as the ones I gave (and thus not in need of distinction) or not relevant to the discussion.

These are really all circular and not illuminating. For example, do we take something for granted because we have overwhelming evidence to justify doing so? Or do we take something for granted by not requiring evidence to accept it?

"Supposition" also has many meanings and the most common one is the one that I explained above was a meaning of "assumption" but clearly not relevant -- something we conditionally accept for reasoning knowing that it makes our conclusions conditional on its truth.

Same thing. Taking for granted is trivially equivalent to divorcing from justification or "blessing". When we "take something for granted" we exempt it from further skepticism, even if that skepticism is later justified.

Again, too vague. Do we do it because evidence justifies it? If so, how is that "assuming"?

That either means divorced from its justification or "blessed" by being exempted from further skepticism. These are the definitions I was talking about.

And, of course, this is even worse than the ones I suggested. Clearly my position would be that believing something to be true without proof is error.

Same thing. These are even worse than my definitions. It is even worse to do these things than to "bless" or divorce from justification. At least in these cases, the assumption was justified in being considered true at some time. These are worse errors, accepting as true things never justified.

The first one of these I covered above. The second is too vague to pin down. It can mean the thing I already said is perfectly okay (assuming something is true to see what conclusions it leads to fully remembering that one's conclusions are conditional) but it can also mean that we accept it as true without proof.

That's not relevant here.

Yes.

I think the only thing you added that I may actually have missed is "assumption" meaning to accept as true and exempt from any skepticism even though there was *never* any evidence to justify accepting the thing assumed. Obviously, I don't think this is ever justified and I think it is always error. (I mostly left this out because it is obviously the case where my argument is so strong that it barely needs to be made. This is obviously bad. This is flipping a coin to decide what to believe.)

Apparently, you're smarter than dictionaries. How special for you. Good luck with that.

 

[Hellbound]

Actually, just htought I'd point out that the entirety of science rest on the assumption that the universe is orderly, homogenous, and understandable.

Carry on.

ETA: And that has been a remarkably useful assumption to make, by the way

 

[JoelKatz]

Actually, just htought I'd point out that the entirety of science rest on the assumption that the universe is orderly, homogenous, and understandable.

If by "assumption" you mean something accepted as true to precisely the extent the evidence justifies accepting it as true and subject to rejection any time the evidence suggests that it is not true, then yes. But by that definition of "assumption", all knowledge and conclusion is an "assumption", except things like "I exist".

There is nothing different about "the universe is understandable" and "gravity is a 1/r^2 force". They are both conclusions that we accept because the evidence justifying them is overwhelming, and they are subject to improvement, modification, or even rejection if the evidence contradicts them.

We needn't really assume the universe is understandable. We simply attempt to understand it, and to the extent we succeed, then it is in fact understandable.

 

[JoelKatz]

Apparently, you're smarter than dictionaries. How special for you. Good luck with that.

If you have any interest in addressing my arguments, let me know. Otherwise, please don't pretend to be responding to me.

 

[Hellbound]

*sigh*.

You can't make a logical argument without an assumption of some sort (also called a premise).

I agree that we've been successful in science, somethign that argues it's assumptions are most likely correct. BUt the assumptions must be made before science itself has any meaning. In other words, scientific method assumes the universe to be understandable, and is developed fromt hat assumption. If the universe is not understandable, then scientific method cannot test that, as it relies on the assumption of an understandable universe that operates according to certain laws.

Take it to an extreme position: How can you prove anythign beyond your own existence? Soliphism, for example, is a prefectly logical conclusion. You really can't disprove that you are the only entity that actually exists, and everything else is some sort of figment/computer program/dream/whatever. However, that's not a useful assumption to make. Experience tells us that it's most useful to accept that there is an external reality, and work from there.

Or another exampel (and yes, these are intentionally silly to illustrate the point), how can you disprove that an object only exists while it is being observed? Logically, it's a consistent stance. And any attempt to gain evidence of it is going to be an observation, thus causign the subject to exist. The scientific method cannot prove thatt he universe does not operate this way. Yet it assumes that this is not the case, because this viewpoint would not be useful.

Utility <> truth.

 

[JoelKatz]

*sigh*.

You can't make a logical argument without an assumption of some sort (also called a premise).

This is true, of course, for formal logic. But human reasoning and human interaction is not formal logic.

In this sense, the "assumption" is carried through to the conclusion and the conclusion is acknowledged to be dependent on the assumption. So if my proof starts "assume x is an integer greater than zero" then whatever conclusion I reach, it is only valid if x is in fact an integer greater than zero.

In actual science and reason, the source of this kind of "necessary assumption" is reality itself. You need them in logic because the reality of any given logic is purely invented.

I agree that we've been successful in science, somethign that argues it's assumptions are most likely correct. BUt the assumptions must be made before science itself has any meaning. In other words, scientific method assumes the universe to be understandable, and is developed fromt hat assumption. If the universe is not understandable, then scientific method cannot test that, as it relies on the assumption of an understandable universe that operates according to certain laws.

These are not assumptions. These are conclusions.

I'll give you a good example. At one time, scientists might well have argued that science is predicated on hard physical determinism -- that state of the universe X+1 can be strictly determined from state X. Some could argue that if not for that, there could be no science at all.

But what happened? When some scientific evidence suggested that hard physical determinism was incorrect, science simply adjusted to the new possibility. Yes, science changed. But new facts and observations *always* change science.

If the universe really is understandable, it is this *fact* that makes science possible. In a universe that was not understandable at all, science would be impossible. But all the assuming in the world wouldn't fix that -- science would still fail.

Take it to an extreme position: How can you prove anythign beyond your own existence? Soliphism, for example, is a prefectly logical conclusion. You really can't disprove that you are the only entity that actually exists, and everything else is some sort of figment/computer program/dream/whatever. However, that's not a useful assumption to make. Experience tells us that it's most useful to accept that there is an external reality, and work from there.

This is why the formal logical notion of proof is not very scientifically useful.

Say there really was no external reality. All the assuming in the world wouldn't help -- scientific conclusions would be false because they wouldn't be about anything.

However, science is useful whether or not there's an external reality. So why do we need to assume that there's an external reality to do science. If science works whether or not there's an external reality, then that assumption is *not* necessary for science to work.

Or another exampel (and yes, these are intentionally silly to illustrate the point), how can you disprove that an object only exists while it is being observed? Logically, it's a consistent stance. And any attempt to gain evidence of it is going to be an observation, thus causign the subject to exist. The scientific method cannot prove thatt he universe does not operate this way. Yet it assumes that this is not the case, because this viewpoint would not be useful.

Same point. If it doesn't, then scientific conclusions are wrong but still useful. So science relies on this to be a fact to be correct and doesn't need this as an assumption to be useful.

And, by the way, some recent QM results suggests that there are some differences in how an object exists when it is not observed. Science is accommodating these new facts perfectly well. We generally act as if objects existed precisely the same when not observed because it is a well-validated conclusion that objects act as if they existed the same when not observed. Now that some evidence calls that into question, we have stopped 'assuming' it. Science is doing just fine figuring out the consequences of this.

 

[JoelKatz]

Here. I'll try to make a peace offering. How about this:

You can say that some things are 'assumptions' in science in the sense that we all perform science as if they were true and we accept that scientific results are only in fact truths if these assumptions are true. However, science is useful whether or not these assumptions are in fact true and you need not actually assume that they are true to produce useful scientific results.

But the important point from my perspective would be that you actually don't ever need to assume them. You can function precisely the same and produce the same useful results whether or not you make the assumptions. And the validity of your conclusions doesn't depend on whether you made the assumptions are not. The validity of your conclusions depends on whether the assumptions are in fact true, which is of course completely beyond your control.

In this case, I would still argue that making the assumptions is error. To the extent you have validated them, they're not assumptions. To the extent you have not validated them, you should accept that your conclusions are useful but not necessarily true unless the things assumed are in fact true.

Science didn't start out by assuming the universe was comprehensible. Quite the reverse, the earliest scientists were definitely unsure of this (and frequently resorted to incomprehensible 'explanations' about gods and tendencies). They simply tried their best to understand the universe, and to the extent they succeeded they proved that it was in fact comprehensible.

 

[bokonon]

Here. I'll try to make a peace offering. How about this:

Keep it.

Recognizing that your personal idiosyncratic definition is simply incorrect, I'll continue to use the word "assumption" as the scientific world does.

I know I promised myself I wouldn't waste more time, but I'm going to give it one last shot anyway. The evidence suggests that it will indeed be time wasted, since you just hand-waved away half a dozen dictionary definitions and went back to your own. Still, you're new here, and may be willing to weigh new information. If you ever decide to reconsider your position based on evidence, here is what one real scientist wrote:

We now assume that:

If two tracts are found to be equal once and anywhere, they are equal always and everywhere.

Not only the practical geometry of Euclid, but also its nearest generalisation, the practical geometry of Riemann, rest upon this assumption. Of the experimental reasons which warrant this assumption, I will mention only one. The phenomenon of the propagation of light in empty space assigns a tract, namely, the appropriate path of light, to each interval of local time, and conversely. Thence it follows that the above assumption for tracts must also hold good for intervals of clock-time in the theory of relativity.

(Albert Einstein, Geometry and Experience)

Anticipating that the reference to "geometry" will provoke a reflexive "sure, a MATHEMATICAL assumption" (though that's not what this is, really), here's another example from the same author:

In this the physical assumption is essential that the relative lengths of two measuring-rods and the relative rates of two clocks are independent, in principle, of their previous history. But this assumption is certainly warranted by experience; if it did not hold, there could be no sharp spectral lines, since the single atoms of the same element certainly do not have the same listing, and since -- on the assumption of relative variability of the single atoms depending on previous history -- it would be absurd to suppose that the masses or proper frequencies of these atoms had ever been equal to one another.

(Albert Einstein, The Meaning of Relativity)

A cursory examination of scientific literature will reveal that scientists use the word as Einstein uses it, and no one but you seems to regard it as a red flag that highlights an error. Science is built on assumptions, and even the most empirical thinkers depend on them to function in an empirical world.

 

[JoelKatz]

It is perfectly fine, in science or any other discipline, to make an assumption in the sense that you assume something is true and then see what conclusions you get, fully recognizing that your conclusions are valid only of the assumption happens to be true.

This what we do when we say "assume X is an integer greater than zero". We don't care whether we have evidence that X is an integer greater than zero or not, it fact, it doesn't matter whether it's the kind of thing we could even have evidence of. (It's not, in this case.) However, we carry through this assumption to the conclusion. That is, we recognize the conclusions is true if (or when, or where) the assumption is true.

We all agree that people do that. We all agree it is fine to do that. Scientists do it. Logicians do it.

Note that this is a formally valid mechanism. It is provable that it is always perfectly fine and safe to make assumptions of this type. There is no harm in making a false assumption. If you assume that 2 is equal to 3, nothing terrible happens, because all the conclusions you reach are explicitly dependent on 2 being equal to 3, which it never is, so the conclusions never apply to anything.

However, when people say that science relies on particular assumptions or that scientists must make assumptions, this is not what they mean. Your reply is equivalent to telling an atheist that because god is everything, he must not believe in everything.

 

[Mirrorglass]

It is perfectly fine, in science or any other discipline, to make an assumption in the sense that you assume something is true and then see what conclusions you get, fully recognizing that your conclusions are valid only of the assumption happens to be true.

<snip>

However, when people say that science relies on particular assumptions or that scientists must make assumptions, this is not what they mean.

<snip>

So in science, it's fine to make assumptions. But when we say that scientists make assumptions, we're talking about something else?

You know, there's something to be said for people who can admit when they've been mistaken.

 

[JoelKatz]

So in science, it's fine to make assumptions. But when we say that scientists make assumptions, we're talking about something else?

Let's go back. The first use of the word "assumption" in this thread, the statement we're discussing all through it when we talk about "assumptions" was this one:

All virtues are practiced in a world in which we never have complete knowledge, but must make assumptions based on what we do know and believe.

Notice the word "but" in there? This sentence says that we don't have complete knowledge and therefore must make assumptions. That is, it's talking about assumptions that we make because we don't have knowledge.

This is the type of assumption that I am saying scientists do not ever need to make and that it is an error to make.

That was my original claim, and I stand by it. It is correct.

There is, however, a completely different kind of assumption that it is perfectly legitimate to make. For example, when we say "assume X is an integer greater than zero" and continue reasoning. This cannot be the type of assumption that was being discussed in this thread (until people tried to play this petty game of gotcha) because it has *nothing* to do with a lack of complete knowledge. We don't assume X is an integer greater than zero because we don't know what X is, we assume X is an integer greater than zero because we are interesting in seeing what the conclusions are for the case where X happens to be greater than zero.

There is another equally important problem with the original claim beyond just the type of assumption it's talking about. The process by which it's saying we use assumptions is wrong to. Here's the original claim again.

All virtues are practiced in a world in which we never have complete knowledge, but must make assumptions based on what we do know and believe.

What this is suggesting is that we may not have enough information to reach a particular conclusion, so we add an assumption, and then we can reach the conclusion. But this is an obviously invalid form of reasoning. If we don't have enough information to reach a conclusion, assumptions don't add information. All they allow us to do is pretend to reach a conclusion which we actually do not know to be so.

What this suggests is that a conclusion can be more certain than the reasoning on which it is based by the addition of an assumption (which 'blesses' an uncertain claim, exempting it from skepticism). This is incorrect, and this is invalid.

Now, if you construe the original claim in completely non-standard and odd way of saying that scientists make assumptions in the formal logic sense, it's trivially true. But that would do nothing to make the point that this was originally stated to make. So it would turn it into a non-sequiter, again equivalent to telling an atheist they don't believe in everything.

 

[Mirrorglass]

Let's go back. The first use of the word "assumption" in this thread, the statement we're discussing all through it when we talk about "assumptions" was this one:

Notice the word "but" in there? This sentence says that we don't have complete knowledge and therefore must make assumptions. That is, it's talking about assumptions that we make because we don't have knowledge.

This is the type of assumption that I am saying scientists do not ever need to make and that it is an error to make.

That was my original claim, and I stand by it. It is correct.

There is, however, a completely different kind of assumption that it is perfectly legitimate to make. For example, when we say "assume X is an integer greater than zero" and continue reasoning. This cannot be the type of assumption that was being discussed in this thread (until people tried to play this petty game of gotcha) because it has *nothing* to do with a lack of complete knowledge. We don't assume X is an integer greater than zero because we don't know what X is, we assume X is an integer greater than zero because we are interesting in seeing what the conclusions are for the case where X happens to be greater than zero.

There is another equally important problem with the original claim beyond just the type of assumption it's talking about. The process by which it's saying we use assumptions is wrong to. Here's the original claim again.


What this is suggesting is that we may not have enough information to reach a particular conclusion, so we add an assumption, and then we can reach the conclusion. But this is an obviously invalid form of reasoning. If we don't have enough information to reach a conclusion, assumptions don't add information. All they allow us to do is pretend to reach a conclusion which we actually do not know to be so.

What this suggests is that a conclusion can be more certain than the reasoning on which it is based by the addition of an assumption (which 'blesses' an uncertain claim, exempting it from skepticism). This is incorrect, and this is invalid.

Now, if you construe the original claim in completely non-standard and odd way of saying that scientists make assumptions in the formal logic sense, it's trivially true. But that would do nothing to make the point that this was originally stated to make. So it would turn it into a non-sequiter, again equivalent to telling an atheist they don't believe in everything.

Let's try this.

- Has anyone ever agreed with you on this matter?
- Have several people disagreed with you?
- Do you believe you are infallible, or at least far more likely to be correct that any other person, despite those other people agreeing with each other?
- If not, why do you insist that you know the real meaning of a word, despite everyone else, including dictionaries and actual scientists, clearly disagreeing with you?

 

[bokonon]

All virtues are practiced in a world in which we never have complete knowledge, but must make assumptions based on what we do know and believe.

Notice the word "but" in there? This sentence says that we don't have complete knowledge and therefore must make assumptions. That is, it's talking about assumptions that we make because we don't have knowledge.

Because we don't have complete knowledge. You keep trying to shoehorn it into a situation where we apparently don't have ANY knowledge and are simply simply asserting something arbitrary - your "assume X is an integer greater than zero" example.

That's clearly not the kind of assumption Einstein is making. He's assuming something about the real world, based on incomplete knowledge. He says his assumption is "warranted by experience" -- the evidence of spectral lines is consistent with the assumption he's making, and making a contrary assumption would lead to a situation he terms "absurd," that is, inconsistent with the reality he's observed. It's still an assumption, not something he can prove, but something that he's willing to consider provisionally true while he explores the implications.

Scientists do this all the time. We assume the spectral lines we see in starlight represent the same elements as the spectral lines we see in the flame of a bunsen burner. We assume gravity operates the same way in the Andromeda galaxy as it does in our own. We assume the speed of light in a vacuum is constant. It is not an error to make such assumptions. Making such assumptions enables scientists to make progress by building on the work of others, rather than spending their time replicating centuries of research.

 

[JoelKatz]

If not, why do you insist that you know the real meaning of a word, despite everyone else, including dictionaries and actual scientists, clearly disagreeing with you?

I'm not talking about the "real meaning" of the word "assumption". It means whatever people mean by it when they use it, and I and others have amply explained the range of possible things a person might mean by "assumption".

However, in this case, it was quite clear what was meant by "assumption". The first person to use it (which wasn't me) put it in a context where it could really only mean one thing -- something you treat as true despite a lack of evidence to justify treating it in that way.

I responded using that same meaning of 'assumption'. Then someone else turned around and said that I was wrong using a different meaning of 'assumption' (something whose truth is not important, but that we suppose is true to find dependent implications which we acknowledge are dependent on the truth of the thing assumed).

This is the same trick a theist might use when an atheist says he doesn't believe in God. "God is everything. You don't believe in everything." Then he finds some dictionary or something that lists "everything" as a possible meaning for god and accuses the atheist of thinking he's "smarter than the dictionary".

It's an utterly dishonest tactic, and you may wish to consider which side of it you'd prefer to be on.

 

[JoelKatz]

How about this peace offering: Yes, I concede it, scientists must make assumptions. These assumptions, however, always consist of either:

1) treating something as true to precisely the extent the evidence justifies treating it as true, or

2) reaching conclusions that are explicitly dependent on the truth of the thing assumed.

I'd prefer not to be bogged down in something nobody thinks it relevant as people continue to try to pursue a senseless and meaningless 'gotcha'.