Nocterro wrote: Philosopher William Lane Craig has often stated, as one of the conditions of a good argument, that the premises must be more plausible than their negations. I disagree with this, on the grounds that it does not always apply – there are counterexamples. Consider this:

1. My neighbor’s dog is outside.
2. It is raining.
C. My neighbor’s dog is outside and it is raining.

This argument is valid – the conclusion follows from the inference rule known as “conjunction introduction”: if p is true, and q is true, then the conjunction p and q is true.

Now, it might be quite plausible, when considered alone, that my neighbor’s dog is outside; after all, his dog is almost always outside. It might also be very plausible that it is raining; perhaps I have looked outside and seen that it is raining. However, I might not be very certain at all that the conclusion is true – who would leave their dog outside in the rain? Should I think it’s plausible to accept this conclusion, just because both 1 and 2 are plausible? Surely not.

One might object by saying that 1 is not plausible because it is raining. This, however, is erroneous; and even supports my point. To say such is not to consider the plausibility of 1 at all; rather, one is instead actually commenting on the plausibility of the conclusion.

So, when should we accept the conclusion of an argument? I employ a modification of Craig’s method. First, I check the argument’s validity. If the argument is valid, I put all of the premises on the “left”, and the negation of the conclusion on the “right”. I then ask myself which is more plausible (or, which “side” I am more certain of. If it is the left, I accept the conclusion of the argument. If the right, I do not. For example:

Left:
1. My neighbor’s dog is outside.
2. It is raining.

Right:
C/N. Not (My neighbor’s dog is outside and it is raining).

If I am more certain of the conclusion’s negation (perhaps because I believe that my neighbor is home, and cares for his dog), then I do not accept the argument.

Let’s run through another example, with an argument often proffered by Dr. Craig:

Left:
1. Whatever begins to exist has a cause.
2. The universe began to exist.

Right:
C/N. not (The universe has a cause).

Of course, different people will have many different views on the plausibility of these premises and conclusion. Most people will not be certain at all that “the universe does not have a cause”. However, one may in fact be even less certain of 1. Depending on rough probabilities, one may be justified in rejecting this argument based on the uncertainty of 1 alone. In any case, these subjective probabilities, combined with this analysis of what makes an argument “good”, serve very well to explain why certain arguments are convincing to some but not to others.

Craig responds:

It’s scary how really desperate these people are becoming! Far from raising valid points, Pranav, these objections are just worthless, based on fundamental misunderstandings. The fellas who posted these criticisms on You Tube, if they continue their study of philosophy, are going to be very embarrassed someday about these videos.

Let me back up and take a run at your question. What makes for a sound deductive argument? The answer is: true premisses and valid logic. An argument is sound if the premisses of the argument are true and the conclusion follows from the premisses by the logical rules of inference. If these two conditions are met, then the conclusion of the argument is guaranteed to be true.

However, to be a good argument, an argument must be more than just sound. If the premisses of an argument are true, but we have no evidence for the truth of those premisses, then the argument will not be a good one. It may (unbeknownst to us) be sound, but in the absence of any evidence for its premisses it won’t, or at least shouldn’t, convince anyone. The premisses have to have some sort of epistemic warrant for us in order for a sound argument to be a good one.

This is why question-begging arguments are not good arguments. A person is guilty of begging the question if his only reason for believing in a premiss is that he already believes in the conclusion. For example, suppose you were to present the following argument for the existence of God:

1. Either God exists or the moon is made of green cheese.
2. The moon is not made of green cheese.
3. Therefore, God exists.

Now this is a sound argument for God’s existence: its premisses are both true and the conclusion follows from the premisses by the rules of logic (specifically, disjunctive syllogism). Nevertheless, the argument is not any good because the only reason for believing the first premiss to be true is that you already believe that God exists (a disjunction is true if one of the disjuncts is true). But that’s the argument’s conclusion! Therefore, in putting forward this argument you’re reasoning in a circle or begging the question. The only reason you believe (1) is because you believe (3).

So, soundness is not sufficient for making an argument a good one. Something more is needed concerning the warrant the premisses have for us. Following the lead of George Mavrodes (Belief in God, 1970) and Steve Davis (God, Reason and Theistic Proofs, 1997), I’ve argued that what is needed is that the premisses be not only true but more plausible than their opposites or negations. If it is more plausible that a premiss is, in light of the evidence, true rather than false, then we should believe the premiss.

I trust that this clears up the gross misunderstanding propagated in a You Tube video that when I say that the premisses of a good argument must be more plausibly true than their negations, I’m positing a range of additional truth values in between true and false. No, I presume the classical Principle of Bivalence, according to which there only two truth values, True and False. There are different degrees of plausibility, not of truth, given the varying amounts of evidence in support of one’s premisses.

Moreover, in a valid deductive argument, like the kalam cosmological argument, any probabilities assigned to the premisses are not used to calculate the probability of the conclusion. (I actually prefer to speak of plausibility rather than probability to avoid the problem that it is often difficult to assign probability values to the premisses; but never mind.) If the premisses are true, then it follows necessarily that conclusion is true, period. It’s logically fallacious to multiply the probabilities of the premisses to try to calculate the probability of the conclusion. That’s why you wind up with the clearly wrong results that you did. In a sound deductive argument the most we can say about the probability of the argument’s conclusion is that it cannot be less than some lower bound; but it could be as high as 100%.

So with respect to your first example, we have here a valid deductive argument, since from (2) and (3), we may infer

3*. A&B

and from (1) and (3*) it follows logically that (4). All we need to find out is whether there are better reasons to believe (1), (2), and (3) rather than their opposites. If there are, then you have a good argument for (4). The probability of (4) doesn’t even enter the picture.

As for your second example, this is also, as you note, a valid argument. So you just need to find out whether the evidence makes each premiss more likely to be true than its negation. The misgiving you share is simply evidence that (2) may not be more plausible than its negation. You’re entitled to look at all the evidence relevant to (2). If it’s raining or 40 degrees below zero or you heard your wife say your neighbor was taking his dog to the vet today, etc., you may well have good grounds for thinking (2) is not true. You might know, e.g.,

1*. If it is raining, my neighbor takes his dog inside.

It follows from (1) and (1*) that (2) is false. But if, on balance, the evidence supports (1) and (2) rather than their opposites, then you’ve got a good argument for (3).

So if these are really “the main issues raised atheists and skeptics on the Internet against [my] third criterion,” we’re in great shape, and they are in deep trouble.

There also seem to be some other counter-intuitive implications of the Cartesian view.  Since the body is the property of an immaterial soul, and since property can be bought and sold, prostitution and selling oneself into slavery would seem to be morally permissible.  Moreover, just as one’s stereo, car, and house are his property, debt-collectors and the government may seize one’s body and force him into slavery, given that they have a sufficient reason for doing so.

A better approach (And this happens to be my own view) would be to defend a form of hylomorphism in which one’s body and soul are seen as interconnected.  This view is defended by scholars such as Robert P. George, Francis Beckwith (I think), and J. P. Moreland.

The question of the historicity of Jesus’ resurrection has been repeatedly probed, investigated and debated. And the results have varied widely. Perhaps some now regard this issue as the burned-over district of New Testament scholarship. Could there be any new and promising approach to this problem?

Yes, answers Michael Licona. And he convincingly points us to a significant deficiency in approaching this question: our historiographical orientation and practice. So he opens this study with an extensive consideration of historiography and the particular problem of investigating claims of miracles. This alone is a valuable contribution.

But then Licona carefully applies his principles and methods to the question of Jesus’ resurrection. In addition to determining and working from the most reliable sources and bedrock historical evidence, Licona critically weighs other prominent hypotheses. His own argument is a challenging and closely argued case for the historicity of the resurrection of Jesus, the Christ. Any future approaches to dealing with this “prize puzzle” of New Testament study will need to be routed through The Resurrection of Jesus.

Good God & Evil World (in 18 Minutes) from Paul Copan on Vimeo.

We look forward to seeing you there! If you decide not to join, there will be dire consequences.

Philosophers use the words possible, impossible, necessary, actual, and contingent very differently as opposed to how they are used in popular circles.  In philosophy, these terms are referred to as modalities and are understood in terms of possible worlds.

A possible world is simply a way things could have been.  They’re a fictional heuristic tool used by philosophers to analyze modal notions.¹  It’s important to keep in mind that possible worlds semantics have nothing to do with multiverse theory — the two are completely different.  Whereas multiverses exist in the actual world, possible worlds do not.

For dummies!

The possible world in which we live in is the actual world, whereas a world in which the proposition “John McCain is the 44th President of the United States” is true is a possible world.  Possible worlds can range from being almost completely similar to the actual world, or they can be worlds which are almost completely dissimilar.  For example, there exists a possible world in which planets are triangular and have orbiting teapots as moons; and Bertrand Russell is orbiting the sun.  There are two important distinctions within modality: de dicto and de re.  De dicto (of the proposition) modality applies to propositions, whereas de re (of the thing) modality applies to entities.

A proposition is necessarily true if and only if it is true in all possible worlds.  That is, there are no circumstances under which it can be false.  An example of a necessarily true proposition is “5+5=10.”  There exists no state of affairs in which 5+5 can equal anything other than 10.  By contrast, a proposition such as “A bachelor is married” is necessarily false (or impossible) if and only if it is false in every possible world.  In between these two, a proposition is contingently true if and only if it is true in some possible worlds.  ”There exist bears in Yosemite National Park” is an example of a contingently true proposition.

Similar to de dicto modality, a being is necessary if and only if it exists in all possible worlds.  God, for example, must exist in all possible worlds by virtue of being a maximally great being.  A married bachelor, however, exists in no possible world by virtue of being self-contradictory and hence is necessarily non-existent.  Finally, bears are contingent beings because they exist on some possible worlds.

It’s important to note the difference between de dicto and de re modality.  Let’s say that I am going to bed at 10′o clock.  In this case, the de dicto proposition “The time in which I go to bed is necessarily even” is true.  However, the de re version of this proposition (“Necessarily, the time in which I will go to bed is even”) is patently false.  The differences can be summed up this way:

De dicto: X is necessarily Y
De re:  Necessarily, X is Y

There are of course many other nuances, but I hope this will suffice for a brief introduction to possible worlds.

1. Some philosophers, David Lewis being one notable example, believe possible worlds to actually exist

Part II | III | IV | V | VI| VII

Consider the following case: You are making a solo trip across the Atlantic in your yacht, and halfway there you hear the muffledsounds of a person coming out of a coma. It turns out that this person was conked on the head and tossed into your boat by gangsters, the day you left port. Now your engine breaks so it will take 9 months for you to get back. You have enough food stored to either feed yourself in comfort for 9 moths [sic] or to barely keep both you and the involuntary-stow-away alive. Are you morally obliged to share your food with the involuntary stow away?

Intuitively (and perhaps legally) you are. It would not be morally permissible to let the person accidentally trapped on your yacht starve to death rather than share your food with them. But how does this case differ from the violinist example?  The amount of sacrice required, the fact that you are blameless in creating the situation of dependence, the fact that the space and resources which the person requires belong to you (you bought the food, and the yacht) are all the same.

Perhaps something of importance turns on the fact that the violinist needs ’access to’ your body whereas the involuntary-stow-away merely needs access to your possessions? Firstly, giving this answer requires us to draw a distinction between needing use your body to save someone (if we suppose the stow away is weak enough that you need to use your body to e.g. carry your food over to them or get it down from a tall shelf this does not change most people’s moral intuitions) as opposed to a suffering person needing ‘access to’ your body in some richer sense which applies to the violinist. It’s not clear that this can be done in a principled way.

Secondly, even if can suitably specify the kind of relationship the violinist needs to be in to your body, this doesn’t seem sufficient to drive the intuition that it’s permissible to refuse aid. For example, the violinist needs to cling onto your body for a certain period of time, but intuitively if this isn’t sufficient to make it permissible to refuse aid. For example, if you are naturally buoyant person in a shipwreck and a small person will drown if they don’t cling onto your shoulder for an hour you obliged to let them.

Well, perhaps there’s some morally significant distinction between the inside and the outside of one’s body – so that what prevents you from being obliged is that the violinist would need to use your blood (i.e. have access to the inside of your body)? But, if we suppose that you had to stay in bed back to back with a stranger for 9 months anyway for reasons of your own health, it doesn’t seem like it would be permissible to refuse to let the violinist take this role and plug into your circulatory system as well. If this is the right verdict about the yacht case, and there is no morally relevant difference between this case and that of the violinist we must conclude that Thompson is wrong, and it is not permissible to unplug the violinist.