How do we approach a new proposition?

Create a topic and discuss! No subject is off limits, but moderators have the right to remove asshat posts. What's an asshat post? Selling stuff, trolling, harassing--the usual stuff you don't want to see either. Happy posting!
Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Thu Oct 18, 2018 5:41 am

So, let us take an example of a real-life proposition, and apply our new tools to it:

In Australia, there is a mammal that lays eggs, has fur, swims underwater, and has venomous spurs.Oh, and it's a marsupial.

Mammals are defined as a warm-blooded creature having fur and giving live birth to its young. So

GP: If it is a mammal then it does not lay eggs.
SP: Platypuses lay eggs.
C: A platypus is not a mammal.

GP: Mammals are not venomous.
SP: Platypuses are venomous.
C: Therefore platypuses are not mammals.

I've used Modus Ponens in both cases here, denying by denying. But for the SPs, I used a double negative, that is, I contradicted the consequent (denying by denying) by making a positive statement, because the consequent was already stated as a negative. It is more common to see the negative in the SP, but so long as the consequent and the specific premise are contradictories, Modus Ponens is properly used, and we have denied the consequent.

"No mammals lay eggs" (strong negation, SEP), is contradicted by "Some mammals (this one) lays eggs" (weak affirmation, SIP).

Now, does this prove that platypuses don't exist? No.
Does it prove that Australia doesn't exist? No.
Does it prove that platypuses are not mammals? yes, GIVEN our definitions of mammals and platypuses, both of which give us our premises.

Remember that a syllogism fails under three conditions:
1.) If there is an ambiguous term,
2.) If the conclusion does not properly follow using modus tollens or modus ponens, OR
3.) If one or more premises is false.

So, do platypuses really exist? Honestly? Really?
EGO TE ABSOLVO, and there's nothing you can do about it.

User avatar
SEG
Posts: 1869
Joined: Tue Feb 27, 2018 1:59 pm

Re: How do we approach a new proposition?

Post by SEG » Mon Oct 22, 2018 4:11 am

Og3 wrote:
Thu Oct 18, 2018 5:41 am
So, let us take an example of a real-life proposition, and apply our new tools to it:

In Australia, there is a mammal that lays eggs, has fur, swims underwater, and has venomous spurs.Oh, and it's a marsupial.

Mammals are defined as a warm-blooded creature having fur and giving live birth to its young. So

GP: If it is a mammal then it does not lay eggs.
SP: Platypuses lay eggs.
C: A platypus is not a mammal.
Echidnas are also mammals and lay eggs
GP: Mammals are not venomous.
SP: Platypuses are venomous.
C: Therefore platypuses are not mammals.
Just like Ed Sullivan, I have a really shrew tonight, in fact I have two:
Eurasian water shrew (Neomys fodiens)
Northern Short-tailed Shrew (Blarina brevicauda)
They are mammals that are venomous.
I've used Modus Ponens in both cases here, denying by denying. But for the SPs, I used a double negative, that is, I contradicted the consequent (denying by denying) by making a positive statement, because the consequent was already stated as a negative. It is more common to see the negative in the SP, but so long as the consequent and the specific premise are contradictories, Modus Ponens is properly used, and we have denied the consequent.

"No mammals lay eggs" (strong negation, SEP), is contradicted by "Some mammals (this one) lays eggs" (weak affirmation, SIP).

Now, does this prove that platypuses don't exist? No.
Does it prove that Australia doesn't exist? No.
Does it prove that platypuses are not mammals? yes, GIVEN our definitions of mammals and platypuses, both of which give us our premises.
No, there are lots more biological criteria that define mammals that you haven't listed, they have a neocortex, three middle ear bones, a lower jaw made of a single bone, a hairy body covering, a thoracic diaphragm, and a four-chambered heart. So you your premises are incomplete. Do I get a star?
Premise One: If a compassionate God exists, then he would do things just as a compassionate person would.
Premise Two: God doesn't do things as a compassionate person would.
Conclusion: Therefore, a compassionate God does not exist.

Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Tue Oct 23, 2018 7:47 pm

SEG wrote:
Mon Oct 22, 2018 4:11 am
Og3 wrote:
Thu Oct 18, 2018 5:41 am
So, let us take an example of a real-life proposition, and apply our new tools to it:

In Australia, there is a mammal that lays eggs, has fur, swims underwater, and has venomous spurs.Oh, and it's a marsupial.

Mammals are defined as a warm-blooded creature having fur and giving live birth to its young. So

GP: If it is a mammal then it does not lay eggs.
SP: Platypuses lay eggs.
C: A platypus is not a mammal.
Echidnas are also mammals and lay eggs
GP: Mammals are not venomous.
SP: Platypuses are venomous.
C: Therefore platypuses are not mammals.
Just like Ed Sullivan, I have a really shrew tonight, in fact I have two:
Eurasian water shrew (Neomys fodiens)
Northern Short-tailed Shrew (Blarina brevicauda)
They are mammals that are venomous.
I've used Modus Ponens in both cases here, denying by denying. But for the SPs, I used a double negative, that is, I contradicted the consequent (denying by denying) by making a positive statement, because the consequent was already stated as a negative. It is more common to see the negative in the SP, but so long as the consequent and the specific premise are contradictories, Modus Ponens is properly used, and we have denied the consequent.

"No mammals lay eggs" (strong negation, SEP), is contradicted by "Some mammals (this one) lays eggs" (weak affirmation, SIP).

Now, does this prove that platypuses don't exist? No.
Does it prove that Australia doesn't exist? No.
Does it prove that platypuses are not mammals? yes, GIVEN our definitions of mammals and platypuses, both of which give us our premises.
No, there are lots more biological criteria that define mammals that you haven't listed, they have a neocortex, three middle ear bones, a lower jaw made of a single bone, a hairy body covering, a thoracic diaphragm, and a four-chambered heart. So you your premises are incomplete. Do I get a star?
You get half a star, for realizing that the premises must be true in order for the conclusions to be accurate.

I'd have given you a full star had you said that the two venomous shrews are examples of SIP (some subject are predicate, weak affirmation) and contradict the SEP (no subject are predicate, strong negation) that no mammals are venomous. But you're on the right track.

You get a smiley face.
EGO TE ABSOLVO, and there's nothing you can do about it.

Humanguy
Posts: 259
Joined: Sun Feb 25, 2018 9:48 pm

Re: How do we approach a new proposition?

Post by Humanguy » Wed Oct 24, 2018 2:05 am

Og3 wrote:
Tue Oct 23, 2018 7:47 pm
You get half a star, for realizing that the premises must be true in order for the conclusions to be accurate.

I'd have given you a full star had you said that the two venomous shrews are examples of SIP (some subject are predicate, weak affirmation) and contradict the SEP (no subject are predicate, strong negation) that no mammals are venomous. But you're on the right track.

You get a smiley face.
It needs pointing out that now that you're assigning grades or stars or whatever to SEG's posts, you've handed SEG the right to do the same to you. If I'm wrong then tell me why.

Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Thu Oct 25, 2018 5:17 am

Humanguy wrote:
Wed Oct 24, 2018 2:05 am
Og3 wrote:
Tue Oct 23, 2018 7:47 pm
You get half a star, for realizing that the premises must be true in order for the conclusions to be accurate.

I'd have given you a full star had you said that the two venomous shrews are examples of SIP (some subject are predicate, weak affirmation) and contradict the SEP (no subject are predicate, strong negation) that no mammals are venomous. But you're on the right track.

You get a smiley face.
It needs pointing out that now that you're assigning grades or stars or whatever to SEG's posts, you've handed SEG the right to do the same to you. If I'm wrong then tell me why.
Well, the star and the smiley-face are facetious, and were assigned because he asked for them.

But if I err in either fact or in application, I urge anyone reading to point out my errors; I am like the clerke of Oxford, of whom Chaucer said, "Gladlye wolde he lerne, and gladlye teche."

I may appeal, and I may choose not to wear the assigned grade if I perceive it unjust, but I will willingly listen to any criticisms of my posts, most especially in the subject of logic proper.
EGO TE ABSOLVO, and there's nothing you can do about it.

User avatar
SEG
Posts: 1869
Joined: Tue Feb 27, 2018 1:59 pm

Re: How do we approach a new proposition?

Post by SEG » Thu Oct 25, 2018 12:44 pm

Og3 wrote:
Thu Oct 25, 2018 5:17 am
but I will willingly listen to any criticisms of my posts, most especially in the subject of logic proper.
You will willingly listen to ANY criticisms of your posts? Isn't that a hasty generalisation? How about if Claire wants to criticise your posts citing all of Maria Valtorta's works as evidence?
Premise One: If a compassionate God exists, then he would do things just as a compassionate person would.
Premise Two: God doesn't do things as a compassionate person would.
Conclusion: Therefore, a compassionate God does not exist.

Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Thu Oct 25, 2018 7:29 pm

I will listen, and then politely ignore it all.
EGO TE ABSOLVO, and there's nothing you can do about it.

Claire
Posts: 1155
Joined: Fri Mar 02, 2018 8:25 am

Re: How do we approach a new proposition?

Post by Claire » Sat Oct 27, 2018 6:08 am

Og3 wrote:
SEG wrote:
Og3 wrote:...but I will willingly listen to any criticisms of my posts, most especially in the subject of logic proper.
You will willingly listen to ANY criticisms of your posts? Isn't that a hasty generalisation? How about if Claire wants to criticise your posts citing all of Maria Valtorta's works as evidence?
I will listen, and then politely ignore it all.
Because?

Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Tue Oct 30, 2018 8:46 am

So this leads us to the next point, and that is the reliability of our premises. Without reliable premises, we cannot deduce.

Unfortunately, at the very lowest level, we are building on quicksand. We cannot build anything through deduction without laying a foundation through induction. Induction is the process of making an observation, and from this, assuming an axiom. For example, I see the sun rise today. I know that the sun has risen, on average, 365.248 times per year while I have been alive. From these observations, I assume that the sun will continue to rise in a recognizable and orderly pattern for the foreseeable future, into perpetuity.

Is this a reliable axiom? Well, most likely, because we have never known it to be wrong.* But not certainly, because there are similar axioms, similarly constructed, that are not reliable. Bertrand Russell, mathematician and atheist, used to recite the example of a man who owns a hen-house full of chickens. One particular hen observes that the farmer chooses a chicken each night and wrings its neck, so that he can pluck it and eat it for dinner. But the hen assumes that in every observation she has made, she has not been chosen. Therefore she believes that she is safe, and will never be chosen for dinner. Clearly, you see how this is not a reliable conclusion.

So then, we need solid inductive observations, or solid axioms, upon which to build. And here we fall into an abyss. If we assume, as did Kant, that every man is reasonable and will act reasonably with respect to moral issues, and if we assume that reasonable secretly means "Christian" in the broad sense, then we wind up with a Categorical Imperative. Or we can suppose that "I think, therefore I am" and we wind up with Descartes. Or we can assume that "Esse est percipi" (To be is to be perceived) and if we apply it ontologically, we become idealists; if we apply it socially, we become shallow fashionistas.

The assumptions determine the outcome.

This is a critical point, because we may not realize that we have made underlying assumptions in our reasoning. And this is our Achilles Heel, because, in the words of Duhem, “if the predicted phenomenon is not produced, not only is the questioned proposition put into doubt, but also the whole theoretical scaffolding used by the physicist.” That is to say, when we find that we have reached a dead end in our reasoning, it is not sufficient to go back to the last cross-roads and try a different direction. We must question every assumption we have made to that point, right down to our inductive axioms.

That's a lot to digest, so I'll leave that for now. But as an exercise, you are encouraged to apply Duhem's Thesis Against Falsification (the bold line, above) to my Australian Conspiracy theory.

____________________________________________
*cf. Og's Principle of Induction, "As observation increases, the reliability of an induction approaches 100%." (Keep, Og, Caveman Apologetics, 2013, Rock and fire Press).
EGO TE ABSOLVO, and there's nothing you can do about it.

Og3
Posts: 965
Joined: Wed Sep 26, 2018 6:41 am

Re: How do we approach a new proposition?

Post by Og3 » Sun Nov 04, 2018 7:59 am

One interesting phenomenon occurs when our opponent in a discussion raises an argument without using either Modus Tollens or Modus Ponens: We can actually grant the premises ad argumentum and then show that the argument is still wrong.
EGO TE ABSOLVO, and there's nothing you can do about it.

Post Reply