Time for another update of the MTW!

The MTW Reformulated

1. Necessarily, two possible propositions that do not yield a contradiction when in conjunction with one another are compossible. (Premise)

2. Possibly, something presently exists. (Premise)

3. Possibly, there was a past time at which nothing contingent existed. (Premise)

4. Necessarily, if there was a past time at which nothing existed, then nothing would presently exist. (Premise)

5. The conjunction of (2) and (3) does not yield a contradiction. (Premise)

6. Possibly, something necessary exists. (Implied by 1 - 5)

7. Therefore, something necessary exists. (From 6 and S5)

The Argument's Validity

Assume (8): something necessary does not exist. (8) and S5 imply (9): it is not possible for something necessary to exist.

However, we know from (1) and (5) that (10): "something presently exists" and "there was a past time at which nothing contingent existed" are compossible. Let's call this possible world w1. In conjunction with (4), it follows from (10) that (11): there was never a past time in w1 at which nothing existed. Since the only remaining entity that could exist at the time that all contingent things failed to exist is something necessary, it follows that (12): something necessary exists in w1. Because (12) contradicts (9), we may conclude that (9), as well as (8) by extension, are false. Therefore, something necessary exists.

Q.E.D.

A Pro Same-Sex Marriage Argument Refuted in One Sentence

Pro same-sex marriage argument

Response: you can't justify one type of behavior by pointing to other types of bad behavior.

Evolution and the PSR

1. Fundamental entities evolve into more complex entities. (Premise)

2. If the PSR is false, evolution is most likely inexplicable. (Premise)

3. Evolution is explicable. (Premise)

4. Therefore, the truth of evolution implies that the PSR is most likely true. (From 1 - 3)

Since a denial of evolution leads to a conclusion incompatible with naturalism, the naturalist will almost certainly accept (1). In fact, it's hard to think of any contemporary naturalists who would reject the first premise. (3) is true on any realistic account of Darwinian natural selection. This leaves us with premise (2).

Take an inductive form of the PSR: if X exists, then X most likely has an explanation of its existence. If most things do not have explanations, then evolution prima facie has an explicability likelihood of <.5. However, evolution is explicable according to (3). This entails that the PSR is most likely true prima facie.

Possibility Premises in the Modal Third Way

It's no surprise to some of you that the Modal Third Way (MTW) is my favorite contemporary argument for God's existence. What has occurred to me in discussing the argument with those of a skeptical persuasion is that many people are often willing to accept the premises individually, but not in conjunction with one another. Let me explain.

1. Necessarily, if something exists right now, then there was never a past time at which nothing existed. (Premise)

2. Something exists. (Premise)

3. Possibly, there was a past time at which nothing contingent existed. (Premise)

From these three premises alone, along with some definitions, we can begin an argument for the existence of a necessary entity. Assume that a necessary entity does not exist. This implies: Possibly, there was a past time at which nothing existed. However, this contradicts the implication of (1) and (2) - namely, that there was never a past time at which nothing existed.

One way to avoid this conclusion is to deny that (1) and (2) are compossible with (3). In this case, it is contended that while there was never a past time at which nothing existed, it is still possible that there was such a past time. It just so happens that the actual world includes presently existing entities. However, if it had ever been the case in the past that everything contingent failed to exist, then nothing would exist at present.

On the face of it, this objection appears consistent, although perhaps a bit contrived. Nevertheless, the objection does help us to better formulate the argument in such a way that it avoids this conclusion. Let's simply add an additional premise:

4. The states of affairs entailing 1, 2 and 3 are compossible. (Premise)

From this we can infer:

5. Possibly, a necessary entity exists. (Implied by 4)

Then, of course, our modal buddy S5 comes along:

6. Therefore, a necessary entity exists. (From 5 and S5)

Obviously, (4) cannot simply be asserted without support. The skeptic may just dismiss it as impossible. The problem is that there is a good rule of thumb to follow when gauging whether or not a set of states of affairs is compossible, which is that conjunctions of individually possible states of affairs yield a possible conjunction, unless a contradiction is derivable.

For example, p1: "the Boston Red Sox won the 2004 World Series," and p2: "the Chicago White Sox won the 2005 World Series." These propositions are compossible (in fact, we know they're actual). So now, let's take p3: "the Boston Red Sox did not win the 2004 World Series." Both p1 and p3 are possible, but they are not compossible. We know this because their mutual instantiation entails a contradiction.

I suggest that apart from the skeptic's ability to derive a contradiction from the conjunction of (1) through (3), he should admit their compossibility and therefore conclude that a necessary entity exists.

Can the kalam argument be defended inductively?

By "induction," I'm not referring to the scientific evidence, although much can be said about that. Rather, are there inductive philosophical grounds for affirming the KCA's key second premise?

1. Whatever begins to exist has a cause. (Premise)

2. The universe began to exist. (Premise)

3. Therefore, the universe has a cause. (From 1 and 2)

I suppose that (1) can be supported through induction in addition to the ex nihilo principle. Our experience of things that begin to exist leads us to believe that they are caused. As far as (2) is concerned, one could point to the other known aspects of the universe. Are the universe's limitations the result of finite characteristics or infinite ones? The universe's finitude is almost built into the very concept of its having limitations.

With this in mind, what is the probability given the background information and our knowledge of the universe's other qualities that the universe's past is infinite? It would appear to be very low, unless of course we have compelling evidence to believe that it's infinite. But, there just aren't any arguments for the universe's having an infinite past. Skeptics spend almost all of their time trying to answer arguments for the universe's finite past.

Another Revised ACA

I'm not sure which one I prefer:

1. Every dependent entity has a sustaining cause. (Premise)

2. Either there is an independent first cause, or the regress of dependent sustaining causes is infinite. (Implied by 1)

3. The regress of dependent sustaining causes cannot be infinite. (Premise)

4. Therefore, an independent first cause exists. (From 2 and 3)

This version of the ACA does not require the PSR, but only supposes that there are, in fact, some entities that are causally dependent on others.

The Aristotelian Cosmological Argument (ACA) - Revised

I like to revise and rephrase these arguments from time to time, so please forgive me if you've read something similar here a hundred times before.

1. Every contingent entity has a sustaining cause. (Premise)

2. Either there is a necessary first cause, or the regress of contingent sustaining causes is infinite. (Implied by 1)

3. The regress of contingent sustaining causes cannot be infinite. (Premise)

4. Therefore, a necessary first cause exists. (From 2 and 3)

This "necessary first cause" is synonymous with the "ground of being," which is God to those of us with a theistic persuasion.