Re: Goldilocks world

From: Bruno Marchal <>
Date: Mon, 28 Nov 2005 16:04:10 +0100

Hi John,

> Bruno,Hi,
> thanks for your speedy and considerate answer. Your
> examples are so simplistic, as only the science of
> logic can provide. Let me try better examples:
> --- Bruno Marchal <> wrote:
> " For example you can know that "1+1 = 3" is false,
> but
>> in that case you know the *truth* of the proposition
>> " "1+1=3" is false".
> Could we figure anything beyond 101 elementary school
> arithmetics?

Why? The point is just to agree (or agree that we disagree) on some
definition. The point is that nobody can know "something false", as
opposed to knowing that some proposition is false. It is better to
illustrate such nuance with elementary propositions nobody (really)
doubt about (of the kind 1+1 = 2, or "1+1 = 3" is false).

> E.g.: People and scientists, priests, etc. KNEW for
> many centuries, including the early medieval ages that
> the Earth is the center of the world and everything
> rotates around it.

They knew that? Or they believed that ? I don't think it makes sense
to say they knew that, unless you have another definition of knowledge.
It is up to you to explain the difference between belief and knowledge.
Epistemologist generally agree that knowledge verify the

Bp -> p

formula (If I know p then p is true). This is just because the truth is
put in the knowledge by definition. If not, it means we talk on
beliefs. Of course many people pretend that they know some proposition,
and occasionally they are wrong: but then they say (if honest): "ok I
was wrong but I believed it", they does not say "ok I was wrong but I
knew it".
And I do think our definition should be coherent with the way we talk,
unless there is a big reason to depart from the traditional use.

> Then came Copernicus and said: this
> is wrong, the sun is the middlepoint. And people
> though reluctantly, believed it. Then came
> cosmologists and said that is wrong, there is NO
> center, everything - including the Sun is moving
> around. And people believed it finally, in droves.
> Until Eistein came around and procalimed: nothing
> moves around anything, because all movement is
> relative to the others, ---
> the notion that everything rotates around the Earth is
> just as true as any other belief put forward ever
> since. (Warum habe wir die Kröten gefressen?)

But this oscillation is a quite complex things, and the usage of the
word "knowing" here is quite sophisticated (that is why I did limit
myself to very elementary arithmetic exemple).
All what I can say is that if the earh is at the center of the world
then the priest knew it, and poor of us, we believe (wrongly) the
contrary. If the earth is not at the center of the world then the
priests did believed (wrongly) that, and we know better.
But your example includes a notion of relativity which limits its use
for making clear the difference between the notion of belief and

> Popper had the idea that
> nothing in science can be proven as true, only
> falsification is possible, does that mean that all
> science is false?

It just means that all (empirical) science is uncertain.
Actually a large part of analytical science is also uncertain but for
different reasons (and then with comp it can be shown that there are
relations between those different sort of uncertainties), but it would
be senseless to mention them before we agree on the basic vocabulary.

Received on Mon Nov 28 2005 - 11:08:13 PST

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