Disproving Odin - An Experiment in arguing with a theist with Theist logic

[SteveII]

We are rehashing things already discussed. I cannot possibly know what posts you have read. Here is the very first paragraph under the article of Inductive Reasoning:



Just about everything in that paragraph is wrong--starting with your requirements about premises in a syllogism. Read the link above to learn more about an inductive argument. 

As to the percentage question, you do NOT multiply probabilities together to come up with a net probability in a syllogism. The conclusion's probability is equal to the lowest of the premise probabilities. Think about it--the more premises you have that are likely true would reduce the net probability if you multiplied them together. 

The proposition you have stated is:

All things that begin to exist have a cause
The universe began to exist
Therefore the universe had a cause

That is a syllogism.  Syllogisms use deductive reasoning from two or more propositions to reach a conclusion.  If the logic is sound, and all of the propositions are true, the the conclusion follows.  If any proposition is false the  syllogism  fails.  https://en.m.wikipedia.org/wiki/Syllogism  https://www.merriam-webster.com/dictionary/syllogism  http://philosophyterms.com/syllogism/  https://www.britannica.com/topic/syllogism  Look it up.

I should have been clearer. The premises themselves are derived inductively. The syllogism is in the form of a deductive argument. This means exactly what I have been saying. The conclusion is based on the probability of the premises being true. In the case of the argument, it is the vast majority of scientists, philosophers, and regular people that both premises are likely true. Therefore it follows that the conclusion is probably true. There is no logical fallacy or problem with the structure. 

To determine the probability of two or more things all being true you multiply to probability of each thing together.  And yes the probability of both propositions being true will be the same if all chances are 100% nd lower if they are not.  https://www.mathplanet.com/education/pre...-of-events.  Look it up.  It's Pre Calc 101.

If you roll a pair of dice the chance of rolling a six is one in six for each die.  If you want to know what the chances are that at least on of the die will come up six, you add the probabilities together.  So, 1/6 + 1/6 = 1/3. But, if you want to know what the chances are of both die rolling 6, you multiply the probabilites.p 1/6 × 1/6 = 1/36. 

Since both proposition 1 and two must be true for the conclusion to follow, it is correct to multiply the probability of the propositions together to determine the probability that the conclusion is proved as stated by the syllogism. 

The probability that your syllogism proves that the universe has a cause is dependant on both (1) everything that begins to exist having a cause, and  (2) the universe beginning to exist.  So to determine the likelihood that the syllogism proves that the universe has a cause we multiply the probability of the first two propositions together.

That reasoning will not work for inductive reasoning. It just does not. Using your method, the more reasons you list that something might be true, the probability of it being true goes down. That is simply not logically possible, so the principle cannot apply. 

[Edit: Polymath correctly notes that the computation of the probability of the two propositions both being  true would be affected  if the the truth of one proposition makes the other proposition more or less likely.  I agree.  ]

Notice that I did not say that that gives us the absolute probability of whether the universe has a cause because there might other evidence besides your syllogism, that the universe has a cause.  Perhaps you might have inductive evidence that the universe has a cause?

A premise in any syllogism has to have support. If could have a 10 pages of arguments that support a 10 word premises. Fleshing out the KCA alone takes like 40 pages in my reference books (philosophers are very careful in their published works). 

That the universe began to exist can be argued on scientific grounds as well a metaphysical grounds. The most promising models for 50+ years have posited the beginning of the universe. All recent observations continue to confirm it and NEVER undercut it. Of course you can find a fringe theory that says otherwise. Metaphysically speaking, there is no way to rationally believe that an infinite number of events could have already happened. This (and more) translates into premise (2) being much more likely true than not. 

Listen, if you want to hang onto the % of uncertainty in the argument and say it is not convincing, fine. That is the only option open to you. What you cannot show is that the argument is wrong or fallacious.