Can the existence of God be demonstrated by logic?

[McCulloch]

I believe that the following facets of my faith can be demonstrated by logical deduction
1. There is a God

Can the existence of God be demonstrated by logical deduction?

[dusk]

But, most importantly, we have not yet agreed on the meaning of the word God. All this talk about logic, evidence, syllogism, premises and conclusions is meaningless until we know what it is that we are trying to prove. What does it mean that God exists? What is God? How can we even begin the process of discussing the proof of God's existence if we don't know what God is?

I agree that is the main point.
Absolute truth or not logic does get you somewhere.
Yet any proof is meaningless if all it is is a definition.

God is love -> love exists -> therefore god exists

Does no more than define the word god to mean love. That is what makes the cosmological argument so nonsensical to me, because it effectively aims a something so generic it could really be anything.

The first mover must be something that does move itself as it wouldn't be the first mover otherwise.
"Nothing" fits the description.

[ThatGirlAgain]

The first mover must be something that does move itself as it wouldn't be the first mover otherwise.
"Nothing" fits the description.

In the original concept of Aristotle, the Unmoved Mover did not actually move anything, much less create anything. The world had always existed. Motion (change) in the world was 'inspired' by the Unmoved Mover, not initiated by it. This Unmoved Mover did nothing but contemplate itself and cared nothing about the world. It was Aquinas who turned Aristotle on his head to try to match the Biblical God with rather less than excellent results IMO.


http://en.wikipedia.org/wiki/Unmoved_mover

[jimvansage]

~you have logicaly shown that Socrates should be logicaly viewed as mortal. We can assume he is mortal untill we have an augment and/or evedance that sugests that he is not mortal. IF the premices are flawed we must conclude that the conclusion - even if we know it to be true - is one we can not view as logicaly sound.~

SO we assume it to be true unless evidence (could you define what an augment is?) can be presented to the contrary

~We can know this becuase all knowalge of all men show that all men so far have died - in other words- the scientific method is the one that brings us KNOWING. Logic has its place in science~ Yes, it's called inductive reasoning. Is it an empirical fact that "all men so far have died"?

"All things that exist at all can be observed in some way by the scientific method"
Love? Hate? Ideas? Intellectual property? How do we know these things exist?


"how do you know that is true without any way to test the idea?!" - if it is supported by logic, evidence, and there is no logic or evidence to reject the idea forthright

"Only the scientific method can let us KNOW that something is true" - You really see a difference in logic, inductive reasoning, and rationality?

McCulloch - so a syllogism can demonstrate the most probable solution?
I'm honestly not willing to discuss God until we better understand terms governing rationality, logic, proof, inductive and deductive reasoning, etc.

[jimvansage]

While Aristotle couldn't comprehend how an eternal God could have created an eternal universe, the fact of modern physics (and it just so happens the Bible) that the universe had a beginning solves any rational dilemma Aristotle might have had.
Just sayin'

[jimvansage]

I have 100 boxes. You open fifty of them and find that the other fifty are locked.
How can you determine if the fifty locked boxes are empty or contain something?

[Mithrae]

In my view, n things are necessary to demonstrate the existence of God:

1. A definition of what we mean when we use the term God that is not ambiguous, tautological or contradictory. This is not a trivial step. For example, using
   1. God is love.
   2. I love my wife.
   3. Therefore, God exists.
   I think that we can all agree this does not sufficiently meet the requirement. Similarly, God is a spirit does not help much, since that leaves the term spirit undefined. But clearly, before we can meaningfully begin to discuss the existence of God, we must agree on what we mean when we use the word.
2. A valid argument, where the conclusion is warranted by the truth of the propositions.
3. A demonstration that each of the propositions in step 2 are probably true.

Just out of curiosity, you would also contend that a deductive argument could not be made to prove that God doesn't exist, correct?

Lacking any demonstrated instance of a god, the default position would be that there isn't one. If we were talking about the existence of a unicorn, the debate would be ended simply by saying, "Here is one. " Without an example or an valid argument for the existence of X, we can provisionally disbelieve in the existence of X.

I'm curious if you provisionally disbelieve in the existence of the universe?

After all, how might we define the term 'universe'?
- - Is it everything that can be observed? Then apparently many distant stars, galaxies and so on suddenly have become part of this 'universe' over the last century.
- - Is the universe everything which is? Reality itself? Arguing that everything which is exists would be tautologous and obviously an invalid definition by your criterion 1.
- - Is the universe everything of the same type of things which we've commonly observed for millenia and in more scope and detail over recent centuries? That's both ambiguous and, depending on what is meant, probably tautological.

Do let us know what your unambiguous, non-tautological and non-contradictory definition of 'universe' is, or failing that (since you would therefore obviously have no demonstrated instance of a universe) confirm that you provisionally disbelieve in the universe



Edit: Definitions are useful for clarifying meaning and logic, but precise definitions are not preconditions of knowledge and it seems rather short-sighted to assert that to be the case. In every other case that readily springs to mind, we decide that something is - gravity, morality, love, wealth, earth, laws of nature, causality, time etc. etc. - long before determining precisely what something is, and often what is meant by such things remain disputed, ambiguous or tautological even to the present day.

Perhaps McCulloch can explain why God is to be an exception to this?

[McCulloch]

Do let us know what your unambiguous, non-tautological and non-contradictory definition of 'universe' is, or failing that (since you would therefore obviously have no demonstrated instance of a universe) confirm that you provisionally disbelieve in the universe

The universe is the set of all things that, in principle, could be shown to exist. It can be demonstrated that some stuff exists, therefore, the universe is not an empty set. God, on the other hand, is usually defined as a single instance rather than a set of items. Russell, among other philosophers, showed that applying the logical rules of individual instances to sets leads to absurdities. Unless your definition of God looks something like the set of all divine persons, then logically speaking of the existence of the universe and the existence of God must be done differently.

Edit: Definitions are useful for clarifying meaning and logic, but precise definitions are not preconditions of knowledge and it seems rather short-sighted to assert that to be the case. In every other case that readily springs to mind, we decide that something is - gravity, morality, love, wealth, earth, laws of nature, causality, time etc. etc. - long before determining precisely what something is, and often what is meant by such things remain disputed, ambiguous or tautological even to the present day.

Perhaps McCulloch can explain why God is to be an exception to this?

Until we have either a definition or an example, we cannot talk meaningfully of the existence of anything. I see no exceptions, even though I do see room for dispute and ambiguity. Even though the question of whether a virus is alive can be disputed, life does exist. Even though the true nature of what gravity is is still unknown, gravity can be demonstrated to exist. Economists continue to refine what they mean by wealth, yet wealth does exist.

Can the existence of God be demonstrated by logic, without defining what is meant when you use the term god?

[jimvansage]

Does "dark matter" exist outside the [observable] universe then, or are we to assume that such a thing does not exist?

[McCulloch]

Does "dark matter" exist outside the [observable] universe then, or are we to assume that such a thing does not exist?

Dark matter has been shown that it must exist if our mathematical modeling of the universe is accurate. We call it dark matter because its existence and properties can only be inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe. Dark matter is estimated to constitute 84% of the matter in the universe. If our mathematical models are correct, then dark matter exists. If our mathematical models are incorrect, then dark matter may not exist. Even though we cannot yet directly observe it, it is part of the universe, because it is, in principle, observable.

[Mithrae]

Do let us know what your unambiguous, non-tautological and non-contradictory definition of 'universe' is, or failing that (since you would therefore obviously have no demonstrated instance of a universe) confirm that you provisionally disbelieve in the universe

The universe is the set of all things that, in principle, could be shown to exist. It can be demonstrated that some stuff exists, therefore, the universe is not an empty set. God, on the other hand, is usually defined as a single instance rather than a set of items. Russell, among other philosophers, showed that applying the logical rules of individual instances to sets leads to absurdities. Unless your definition of God looks something like the set of all divine persons, then logically speaking of the existence of the universe and the existence of God must be done differently.

Thanks I'm not very familiar with the idea of sets, but hopefully I've understood you well enough to respond.

Talking about things that might be shown to exist seems quite ambiguous. Shown to whom, for starters? You? Me? Certain scientists in specialised fields? All of humanity? The people who, hypothetically, are there at the right time and place, with the right equipment and observational/interpretational approach? Furthermore what isn't certain or impossible can only have some degree of probability, and since that can only be assessed according certain criteria, we must ask what criteria you're proposing for things to be 'shown to exist'? Is the way of thinking we've evolved, our logic, to be considered a valid basis on which to exclude or deduce facts about reality? What about the bodily senses we've evolved? The instruments we've made? The instincts or intuitions we may have?

All of these questions - this vast scope of ambiguity in your chosen definition - is only increased (as far as I can imagine) by talking about what "in principle" could be shown to exist; either that, or you've made it a tautology. If it exists, then in principle there could be some way to show it exists, even if the capacity were not available to actually do so in any foreseeable future. Even in the Stone Age the dark matter which Jim mentioned could in principle be shown to exist, yes? Likewise there's probably things we can't even imagine yet which might in principle be possibly shown to exist (by whatever standards of 'shown to exist' are deemed fit, of course). To say that "set of all things that, in principle, could be shown to exist" exists is obviously a tautology.

I don't think you've actually said that the universe exists in fairness, so if it's your view that the universe does not exist, fair enough. But if it's your view that the universe exists, I think that either I've grossly misunderstood you, or else your definition seems to be both tautological and exceptionally ambiguous. I note also that your definition of the universe requires either that God (or anything prior to the Big Bang) cannot even in principle be shown to exist, or that God or anything before the Big Bang are part of the universe.

Edit: Definitions are useful for clarifying meaning and logic, but precise definitions are not preconditions of knowledge and it seems rather short-sighted to assert that to be the case. In every other case that readily springs to mind, we decide that something is - gravity, morality, love, wealth, earth, laws of nature, causality, time etc. etc. - long before determining precisely what something is, and often what is meant by such things remain disputed, ambiguous or tautological even to the present day.

Perhaps McCulloch can explain why God is to be an exception to this?

Until we have either a definition or an example, we cannot talk meaningfully of the existence of anything. I see no exceptions, even though I do see room for dispute and ambiguity. Even though the question of whether a virus is alive can be disputed, life does exist. Even though the true nature of what gravity is is still unknown, gravity can be demonstrated to exist. Economists continue to refine what they mean by wealth, yet wealth does exist.

Can the existence of God be demonstrated by logic, without defining what is meant when you use the term god?

Broadly understanding what is meant by a term is necessary; having a definition that is entirely unambiguous is often unnecessary and, as in the case of words like 'universe' or 'reality,' even tautology might sometimes be inavoidable. I'll await your comments regarding a definition for universe, my humble counter-example to your suggestion that such precise criteria in definitions are necessary as a first step, but quite simply I'm not seeing why you made that suggestion in the first place. If God were defined as 'love' - though I imagine very few theists would do so - it'd be a pretty ineffectual and benign deity after all.