On 13 Oct 2011, at 22:50, benjayk wrote:
Bruno Marchal wrote:
By saying that no flaw has been found, while people have pointed out
If you are really humble, just don't make any statements about
reasoning is valid or not.
I don't defend any truth but I am still offering a reasoning to you.
If you find it invalid it is your task to find the flaw. That's is by
definition of reasoning.
that you just don't accept as such (whether valid or not is not even
On the contrary, once we are genuinely interested in the topic, that
is what is important. The rest is meta-discussion distracting from the
It seems to me "purely" rational arguments are only especially
arguments, like arguments purely based on belief.
Rational argument are always based on belief, that is, by people ready
to be shown false.
Irrational arguments are based on knowledge, which is never rational,
nor even a rational notion, because it is based on truth. That is why
in science, there is only beliefs, at least if we accept Popper idea
that a scientific proposition has to be refutable. I am not talking on
human scientists, who falls in the trap of believing non fallible, but
on sort of ideal science.
But in some case the reasoning itself cannot be seperated from the
If I don't share the premise that 1+1=2, I can still see that 1+2=3
from that. This may not be the case with all arguments, and it seems
*All* reasoning suppose their premise true for the sake of the
this is the case with COMP.
Comp, on the contrary, warns explicitly that it might be false, and
that: if it is true, this cannot be shown by a rational argument. If a
doctor pretended that science has proved that the brain is a computer,
you better run away, because, IF the brain is a computer THEN no one
can show it to be a computer. This is a subtle point. It is like
"consistency" for a LUM (or for Peano Arithmetic). Peano Arithmetic
can prove that if Peano Arithmetic is consistent, then Peano
Arithmetic cannot prove it.
COMP is very similar with a notion of self-consistency, and it
provides a sort of rational near inconsistency experience.
Bruno Marchal wrote:
A common technic to prove that A entails B consists in supposing A
getting B from that. This does not prove that A is true, it proves
only that IF A is true then B is true.
In many-world terms it means that in all words were A is true, B is
also true. It means there is no world in which A is true and B is not
true. But it does not mean that A is true in all world.
A common technic to prove that A is false, for example, will consists
in assuming A and getting a contradiction from it (like 0 = 1), and
then deducing NOT A, from that, despite the reasoning worked by
supposing A to be true.
So the validity of a reasoning is completely independent of the true
or falsity of the premise.
This may be the case for formal arguments,
It is the case with informal argument too.
but yours isn't strictly formal
(necessarily so because "Yes" doctor, including correct substitution
is not formal and the reasoning has to reference that), and so no
contradiction can be found - or even no contradiction at all.
You can get informal contradiction. That's what Stathis shows up with
Craig's theory. Stathis' reasoning is informal but valid. Craig's
reply is informal but non valid, as Stathis patiently points out.
If you were true, no discussion at all would make sense.
In fact rigorous/non-rigorous has nothing to do with formal/informal.
imply that the reasoning is valid. Otherwise all informal arguments
valid, which is clearly not true.
Of course. But if you find a reasoning non valid, it is up to you to
say where and why specifically.
Bruno Marchal wrote:
Don't bother. You are just wasting your time, frankly I have no
PS I might comment other paragraph, but I am unfortunately very busy,
so I will limit to answer only one paragraph which I might find more
important, or summing up others.
this discussion anymore.
You did really lost me. I did not see your point at all in some of
your late posts. I have begun to answer one, but then some remarks you
did made me realize it would make no sense of trying to answer the
post. I was enjoying discussing with you, but then, all of a sudden,
you lost me through a labyrinth of negative and emotional remarks,
which cannot really been answered.
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