Classic example: If A is part of B and then B is part of C... C is necessarily part of A. — javi2541997

Start here. Do you see the problems?

Start here. Do you see the problems?

To be honest. No, I do not see it.

If A is part of B and then B is part of C... C is necessarily part of A. — javi2541997

I guess you mean something more like: If A is part of B, and C is part of A, then C is also part of B.

One of my university professors (the same one I mentioned in one of my threads) mentioned a similar syllogism, and put into the mouth of a sceptic the following question: How do you know that all men are mortal?

In the first place, we can't know that with certainty until all men have died, and since that includes us we will never be able to know, since even if everyone else died we'd still be alive. And we can't even know with certainty that it is not the case that someone somewhere in the world is, say, 300 years old.

(...)there is nothing logically self-contradictory about an immortal man. We believe the proposition on the basis of induction, because there is no well-authenticated case of a man living more than (say) 150 years; but this only makes the proposition probable, not certain. It cannot be certain so long as living men exist. — Bertrand Russell

No. I guess I am right because I am speaking about parts of one thing.
A is part of B. (so B has parts of A)
B is part of C. (B which has some parts of A, also has parts of C)
Then, C has parts of A because somehow it was dragged from the original roots.

Also I really like the quote of Bertrand Russel you quoted. Specifically:

but this only makes the proposition probable, not certain. It cannot be certain so long as living men exist.

It is interesting how he explains it. Of course we cannot argue against it while living men exist.

According to that logical structure:

1.Bricks (A) are part of a wall (B)

2.A wall (B) is part of a house (C)

3.Therefore, a house (C) is necessarily part of the bricks (A)

... which is obviously fallacious.

You then changed it to: C has parts of A, which is not the same as: C is necessarily a part of A.

... which is obviously fallacious.

You then changed it too: C has parts of A, which is not the same as: C is necessarily a part of A.

I understand your point here but I guess I was typing the same but with more emphasis. Your example is even better than mine. C (the house) has parts of A (bricks) that have to be connected because they depend each other to build a house. So, C necessarily is part A since the moment where the house was built with the those bricks (A).
It is like a chain where the three parts are necessarily connected to build the house. They are not just parts

A is in B
B is in C
A is in C, not C is in A.

Aristotelian syllogisms have three terms called usually S, P, M, for subject (of the conclusion), predicate (of the conclusion) and m (middle, which appears in both premises but does not appear in the conclusion).

Premises themselves are universal (All S is P), particular (Some S are P), affirmative (All, some S are P), or negative (no S are P; some S are not P).

From memory - I'm not counting - there are 216 ways of assembling a syllogism, only about 24 (still from memory) being valid. From these valid are distilled a few rules for the construction of valid syllogisms.

Yours above seems Barbara - a descriptive name for one of the forms of valid syllogisms (google Barbara Celarent). But on close reading it has four terms. Humans, I, my life, and L&D. You can argue that "I" and "my life" are the same thing, but that's not part of the syllogism: the syllogism is invalid because it has four terms. Which is not to be confused with whether the conclusion is true. Conclusions can indeed be true, even if they do not follow in the syllogism.

There are a ton of good books on the subject, even cheap used. Try your library or ask an instructor for a recommendation. And if the book bores you to tears or is incomprehensible, get another book! This isn't rocket science and can be enjoyable as well as useful

I understand your point here. But you used another example. You are talking about A, B and C as indivisible things. I was trying to put an example of a syllogism which parts are some how related each other. This is why I guess Aristotle called it as perfect one
When I said A is part of B (we have here like a component)
B is part of C.
Then, necessarily C has to be part of A when B is already part of A
Like they end up being together.

There are a ton of good books on the subject, even cheap used. Try your library or ask an instructor for a recommendation. And if the book bores you to tears or is incomprehensible, get another book! This isn't rocket science and can be enjoyable as well as useful

Yes! I am looking for buying more like these but I think the issue here is that I am Spanish so I guess when I try to translate it in English by myself I go wrong. Anyways, I going to share with you a pic where I read it from because literally speaks the same argument as yours.

[img]http://

Then, necessarily C has to be part of A when B is already part of A — javi2541997

No. All A is C, some C is A.

No. All A is C, some C is A.

Why some C is A? I am interested in this argument.

Ok.
All m is P
All S is m
All S is P

This the above mentioned Barbara.
Pictorially - visually - this is clear with Venn diagrams. Google Venn diagrams.

The point is that something is said about all of S. But nothing is said about all of P. By the premises, all S is P. So some P is S. But nothing in the argument prevents there being a P that is not S. So it is an invalid conclusion to say that all P is S (even though it may in fact be true).

This notion of qualifying all of something, saying All is, or None are (or some are not, but this is subtle) is called "distribution" - a word that in this usage you just have to get used to. In order to have a valid syllogism all the terms, the S, the P, and the M, must be "distributed" at least once. That means that in the syllogism something must be said about all of the S, P, and M at least once. Failure is called illicit major, illicit minor, or undistributed middle, depending on which term is not distributed. But this is why you need a decent textbook.

Ok. I understand you now.

But this is why you need a decent textbook. — tim wood

I will follow your recommendations. Thanks for helping me :up:

I want to ask the illustrious members of this forum about other perfect syllogism — javi2541997

Also this question is still opened :sweat:

I want to ask the illustrious members of this forum about other perfect syllogism — javi2541997

I'm illustrious enough so I will answer you.

Some Swedes are not Protestants.
All parishioners are Protestants.
Therefore some Swedes are not Parishioners.

This is the Holy Grail of all luminary syllogisms. This is perfect. Even Plato himself would include it as one of the Forms.

--------------

To be honest, there is no such thing as a perfect syllogism. It is like asking what the perfect two numbers are that you can add together to form a sum.

about other perfect syllogism — javi2541997

If you mean other valid forms, here:

https://www.friesian.com/aristotl.htm

Some Swedes are not Protestants.
All parishioners are Protestants.
Therefore some Swedes are not Parishioners. — god must be atheist

Perfect one but somehow this can be refuted which is the main principle of perfect syllogism. I guess at least one parishioner is protestant. So this is why is not “perfect” enough. Nevertheless, when I put previously this one:
All humans have limit lives and are deadly (higher premise)
I am a human. (lower premise)
Therefore, my life is limited and I am deadly (logic conclusion that cannot be refuted because this literally happens).
This literally happens. This is why we cannot refute it because we all are deadly.

To be honest, there is no such thing as a perfect syllogism. It is like asking what the perfect two numbers are that you can add together to form a sum. — god must be atheist

I think name it as perfect is flawed. I am agree with you. But somehow it is difficult to find another exact syllogism as how deadly humans are. This is why I guess Aristotle named it in this way.

If you mean other valid forms, here:

https://www.friesian.com/aris — tim wood

Thank you Tim for providing to me these documents. I will check it out. Syllogisms are one of the topics I love the most in philosophy