In response to two recent posts, here and here, Jacques comments:
I'm mostly persuaded by your recent posts about theism and knowledge, but I disagree about your claim that
"Presumably God can prove the existence of God, if he exists, not that he needs to."
Think of your condition 5 ["It is such that all its premises are known to be true."] if you can prove that p then you can derive p from an argument with premises all of which are known to be true. Suppose that God has some argument A for the conclusion that God exists. As you point out, A will either depend on premises taken to be self-evident, or an appeal to the seeming self-evidence of further premises in sub-arguments for the premises in A that are not taken to be self-evident. But now suppose that there's some premise P such that A is a proof of theism for God only if God takes P to be self-evident and P really is self-evident -- in other words, only if P is 'objectively' self-evident and not just 'subjectively'. Of course, P might well appear to God to be self-evident; it might even appear to him that the objective self-evidence of P is itself objectively self-evident, and so on ad infinitum. But how could He really know, or be rationally entitled to believe, that P really is self-evident in the relevant sense rather than just seeming that way to Him? Sure, if He already knows that God exists, and that He Himself = God, then He can infer that the fact that P seems to him self-evident entails its real objective self-evidence. But how can He know that unless He can prove that He = God?
BV: The question seems to come down to whether or not the distinction between subjective and objective self-evidence applies to God as well as to us. It does apply to us. But I don't see that it applies to God. God's is an archetypal intellect, which implies that divine knowledge is creative of its object, whereas our knowledge is clearly not. If God knows that p by making it the case that p, then there is no logical gap between subjective and objective self-evidence for God.
On the other hand, it could be that God isn't even capable of proving anything. Maybe proofs are only possible for ignorant thinkers (who don't know directly, by acquaintance all the facts). But if He could prove or try to prove things I suspect His situation would be no better than ours with respect to His existence. Of course that conflicts with the (definitional?) fact of His omniscience, but maybe the conclusion should just be that the traditional concept of the Omni- God is incoherent.
BV: The divine intellect is intuitive, not discursive. God knows directly, not mediately via inferential processes. To know something in the latter way is an inferior way of knowing, and as such inappropriate to the divine intellect. Does it follow that God can't prove anything? I would hesitate to say that given the divine omnipotence: if he wanted to construct a proof he could. The point is that he doesn't need to. But we do need to employ inferential process to articulate and amplify our knowledge both deductively and inductively.
The main question, however, was whether WE can prove the existence of God. My answer to that is in the negative. The reason is due to the nature of proof as set forth in my definition. But perhaps you have a better definition.
To theists, I say: go on being theists. You are better off being a theist than not being one. Your position is rationally defensible and the alternatives are rationally rejectable. But don't fancy that you can prove the existence of God or the opposite. In the end you must decide how you will live and what you will believe.
About "Don't fancy that you can prove the existence of God or the opposite," Owen Anderson asks:
How would we know if that claim is itself true? Isn't it is possible that one or the other can indeed be proven?
To formulate my point in the declarative rather than the exhortative mood:
P. Neither the existence nor the nonexistence of God is provable.
How do I know (P) to be true? By reflection on the nature of proof. An argument is a proof if and only if it satisfies all of the following six requirements: it is deductive; valid in point of logical form; free of such informal fallacies as petitio principii; possesses a conclusion that is relevant to the premises; has premises each of which is true; has premises each of which is known to be true.
I say that an argument is a proof if and only it is rationally compelling, or rationally coercive. But an argument needn't be rationally compelling to be a more or less 'good argument,' one that renders its conclusion more or less rationally acceptable.
Now if my definition above gives what we ought to mean by 'proof,' then it is clear that neither the existence nor the nonexistence of God can be proven. Suppose you present a theistic or anti-theistic argument that satisfies the first five requirements. I will then ask how you know that the premises are true. Suppose one of your premises is that change is the conversion of potency into act. That is a plausible thing to maintain, but how do you know that it is true? How do you know that the general-ontological framework within which the proposition acquires its very sense, namely, Aristotelian metaphysics, is tenable? After all, there are alternative ways of understanding change. That there is change is a datum, a Moorean fact, but it would be an obvious mistake to confuse this datum with some theory about it, even if the theory is true. Suppose the theory is true. This still leaves us with the question of how we know it is. Besides, the notions of potency and act, substance and accident, form and matter, and all the rest of the Aristotelian conceptuality are murky and open to question. (For example, the notion of prime matter is a necessary ingredient in an Aristotelian understanding of substantial change, but the notion of materia prima is either incoherent or else not provably coherent.)
To take a second example, suppose I give a cosmological argument the starting point of which is the seemingly innocuous proposition that there are are contingent beings, and go on to argument that this starting point together with some auxiliary premises, entails the existence of God. How do I know that existnece can be predicated of concrete individuals? Great philosophers have denied it. Frege and Russell fanmously held that existence vannot be meaningfully predicated of individuals but only of cncepts and propositional functions. I have rather less famoulsy argued that the 'GFressellina' view' is mstaken, but this is a point of controversy. Furtrhertmore, if existence cannot be meaningfully predicated of individuals, how can individuals be said to exist contingently?
The Appeal to Further Arguments
If you tell me that the premises of your favorite argument can be known to be true on the basis of further arguments that take those premises as their conclusions, then I simply iterate my critical procedure: I run the first five tests above and if your arguments pass those, then I ask how you know that their premises are true. If you appeal to still further arguments, then you embark upon a vicious infinite regress.
The Appeal to Self-Evidence
If you tell me that the premises of your argument are self-evident, then I will point out that your and my subjective self-evidence is unavailing. It is self-evident to me that capital punishment is precisely what justice demands in certain cases. I'll die in the ditch for that one, and pronounce you morally obtuse to boot for not seeing it. But there are some who are intelligent, well-meaning, and sophisticated to whom this is not self-evident. They will charge with with moral obtuseness. Examples are easily multiplied. What is needed is objective, discussion-stopping, self-evidence. But then, how, in a given case, do you know that your evidence is indeed objective? All you can go on is how things seem to you. If it seems to you that it is is objectively the case that p, that boils down to: it seems to you that, etc., in which case your self-evidence is again merely subjective.
The Appeal to Authority
You may attempt to support the premises of your argument by an appeal to authority. Now many such appeals are justified. We rightly appeal to the authority of gunsmiths, orthopaedic surgeons, actuaries and other experts all the time, and quite sensibly. But such appeals are useless when it comes to PROOF. How do you know that your putative authority really is one, and even if he is, how do you know that he is eight in the present case? How do you know he is not lying to you well he tells you you need a new sere in your semi-auto pistol?
If your argument falls afoul of petitio principii, that condemns it, and the diameter of the circle doesn't matter. A circle is a circle no matter its diameter.
Am I Setting the Bar Too High?
It seems to me I am setting it exactly where it belongs. After all we are talking about PROOF here and surely only arguments that generate knowledge count as proofs. But if an argument is to generate a known proposition, then its premises must be known, and not merely believed, or believed on good evidence, or assumed, etc.
"But aren't you assuming that knowledge entails certainty, or (if this is different) impossibility of mistake?" Yes I am assuming that. Argument here.
Can I Consistently Claim to Know that (P) is true?
Owen Anderson asked me how I know that (P) is true. I said I know it by reflection on the concept of proof. But that was too quick. Obviously I cannot consistently claim to know that (P) if knowledge entails certainty. For how do I know that my definition captures the essence of proof? How do I know that there is an essence of proof, or any essence of anything? What I want to say, of course, is that it is very reasonable to define 'proof' as I define it -- absent some better definition -- and that if one does so define it then it is clear that there are very few proofs, and, in particular, that there are no proofs of God or of the opposite.
"But then isn't it is possible that one or the other can indeed be proven?"
Yes, if one operates with a different, less rigorous, definition of 'proof.' But in philosophy we have and maintain high standards. So I say proof is PROOF (a tautological form of words that expresses a non-tautological proposition) and that we shouldn't use the word to refer to arguments that merely render their conclusions rationally acceptable.
Note also that if we retreat from the rationally compelling to the rationally acceptable, then both theism and atheism are rationally acceptable. I suspect that what Owen wants is a knock-down argument for the existence of God. But if that is what he wants, then he wants a proof in my sense of the world. If I am right, that is something very unreasonable to expect.
There is no getting around the need for a decision. In the end, after all the considerations pro et contra, you must decide what you will believe and how you will live.
Life is a venture and an adventure. You cannot live without risk. This is true not only in the material sphere, but also in the realm of ideas.
We should anchor our thought in that which is most certain: the fact of change, the nearness of death, that things exist, that one is conscious, that one can say 'I' and mean it, the fact of conscience. But man does not meditate on the certain; he chases after the uncertain and ephemeral: name and fame, power and position, longevity and progeny, loot and land, pleasure and comfort.
Wealth is not certain, but the grave is. So meditate on death, asking: Who dies? Who survives? What is death? Who am I? What am I?
Death is certain, but the when is uncertain. Do not try to make a certainty out of what is uncertain, or an uncertainty out of what is certain.
"What is your life? You are a mist that appears for a little while and then vanishes." (James 4:14)
Thomas Nagel writes that “whether atheists or theists are right depends on facts about reality that neither of them can prove” [“A Philosopher Defends Religion,” Letters, NYR, November 8]. This is not quite right: it depends on what kind of theists we have to do with. We can, for example, know with certainty that the Christian God does not exist as standardly defined: a being who is omniscient, omnipotent, and wholly benevolent. The proof lies in the world, which is full of extraordinary suffering. If someone claims to have a sensus divinitatis that picks up a Christian God, they are deluded. It may be added that genuine belief in such a God, however rare, is profoundly immoral: it shows contempt for the reality of human suffering, or indeed any intense suffering.
Strawson is telling us that it is certain that the God of Christianity does not exist because of the suffering in the world.
How's that for pure bluster?
What we know is true, and what we know with certainty we know without the possibility of mistake. When Strawson claims that it is certain that the Christian God does not exist, he is not offering an autobiographical comment: he is not telling us that it is subjectively certain, certain for him, that the Christian God does not exist. He is maintaining that it is objectively certain, certain in itself, and thus certain for anyone. From here on out 'certain' by itself is elliptical for 'objectively certain.'
And why is it certain that the Christian God does not exist? Because of the "extraordinary suffering" in the world. Strawson appears to be endorsing a version of the argument from evil that dates back to Epicurus and in modern times was endorsed by David Hume. The argument is often called 'logical' to distinguish it from 'evidential' arguments from evil. Since evidential or inductive or probabilistic arguments cannot render their conclusions objectively certain even if all of their premises are certain, Strawson must have the 'logical' argument in mind. Here is a version:
If God exists, then God is omnipotent, omniscient, and morally perfect.
If God is omnipotent, then God has the power to eliminate all evil.
If God is omniscient, then God knows when evil exists.
If God is morally perfect, then God has the desire to eliminate all evil.
If evil exists and God exists, then either God doesn’t have the power to eliminate all evil, or doesn’t know when evil exists, or doesn’t have the desire to eliminate all evil.
Therefore, God doesn’t exist.
It is a clever little argument, endlessly repeated, and valid in point of logical form. But are its premises objectively certain? This is not the question whether the argument is sound. It is sound if and only if all its premises are true. But a proposition can be true without being known, and a fortiori, without being known with certainty, i.e., certain. The question, then, is whether each premise in the above argument is objectively certain. If even one of the premises is not, then neither is the conclusion.
Consider (5). It it certain that evil exists? Is it even true? Are there any evils? No doubt there is suffering. But is suffering evil? I would say that it is, and I won't protest if you say that it is obvious that it is. But the obvious needn't be certain. It is certainly not the case that it is certain that suffering is evil, objectively evil. It could be like this. There are states of humans and other animals that these animals do not like and seek to avoid. They suffer in these states in a two-fold sense: they are passive with respect to them, and they find the qualitative nature of these states not to their liking, to put it in the form of an understatement. But it could be that these qualitatively awful states are axiologically neutral in that there are no objective values relative to which one could sensibly say something like, "It would have been objectively better has these animals not suffered a slow death."
The point I am making is that only if suffering is objectively evil could it tell against the objective existence of God. But suffering is objectively evil only if suffering is objectively a disvalue. So suffering is objectively evil and tells against the existence of God only if there are objective values and disvalues.
Perhaps all values and preferences are merely subjective along with all judgments about right and wrong. Perhaps all your axiological and moral judgments reduce to mere facts about what you like and dislike, what satisfies your desires and what does not. Perhaps there are no objective values and disvalues among the furniture of the world. I don't believe this myself. But do you have a compelling argument that it isn't so? No you don't. So you are not certain that it isn't so.
And so you are not certain that evil exists. Evil ought not be and ought not be done, by definition. But it could be that there are no objective oughts and ought-nots, whether axiologically or agentially. There is just the physical world. This world includes animals with their different needs, desires, and preferences. There is suffering, but there is no evil. Since (5) is not certain, the conclusion is not certain either.
Now consider (2): If God is omnipotent, then God has the power to eliminate all evil. Is that certain? Is it even true? Does God have the power to eliminate the evil that comes into the world through finite agents such as you and me? Arguably he does not. For if he did he would be violating our free will. By creating free agents, God limits his own power and allows evils that he cannot eliminate. Therefore, it is certainly not certain that (2) is true even if it is true. Reject the Free Will Defense if you like, but I will no trouble showing that the premises you invoke in your rejection are not certain.
Pure ideologically-driven bluster, then, from an otherwise brilliant and creative philosopher.
In his magisterial Augustine of Hippo, Peter Brown writes of Augustine, "He wanted complete certainty on ultimate questions." (1st ed., p. 88) If you don't thrill to that line, you are no philosopher. Compare Edmund Husserl: "Ohne Gewissheit kann ich eben nicht leben." "I just can't live without certainty." Yet he managed to live for years after penning that line into his diary, and presumably without certainty.
I would say that the ability to tolerate uncertainty without abandoning the quest for certainty is a mark of intellectual and spiritual maturity. A truth seeker who can tolerate uncertainty is one who will not seek false refuge in dogmas that provide pseudo-certainty. I cannot help but think of Islamo-terrorism in this connection. Had Muhammad Atta and the boys entertained some doubts about the bevy of black-eyed virgins awaiting them at the portals of paradise, they and three thousand others might still be alive.
The trick is to tolerate uncertainty without becoming either a skeptic or a dogmatist.
There is a difference between subjective and objective certainty. If subject S is subjectively certain that p, it does not follow that p is true. That would follow only if S were objectively certain that p. But objective certainty appears attainable only with respect to one's own mental states. I am both subjectively and objectively certain that I have a headache now. This is because the esse of the headache = its percipi. Its being is its being perceived. It therefore cannot be intelligibly supposed that I merely seem to have a headache now, while in reality I do not. With respect to a physical object or state, however, appearance and reality can come apart, and what is subjectively certain can turn out to be false: my seeming to see a mountain is no guarantee that there is a mountain. My seeming to feel elated, however, just is my being elated.
What about states of affairs that involve neither mental data nor physical objects? If S is subjectively certain that torture is always morally impermissible, and T is subjectively certain that torture is sometimes morally permissible, then one of the two must be wrong, which shows that subjective certainty is no proof of objective certainty.
What about this last proposition however, namely, the proposition that apart from mental states, subjective certainty does not entail objective certainty? Is its truth merely subjectively certain, or is it also objectively certain? It is objectively certain. One sees that subjective certainty can exist without objective certainty from the fact that two subjects, S and T, can be subjectively certain of contradictory propositions. Here the mind grasps a truth about a state of affairs transcendent of one's mental state and does so with objective certainty.
I conclude that there are some propositions the truth of which can be grasped with objective certainty even though these propositions are not about such mental data as pleasures and pains. The mind has the power to transcend its own states and not only to know, but to know with objective certainty, truths whose truth is independent of mind. That is amazing.
One some days, existence strikes me as the deepest and most fascinating of philosophical topics. On other days, I give the palm to time: "What, then, is time? If no one asks me, I know; if I want to explain it to someone who does ask me, I do not know." (Augustine, Confessions, Bk. 11, Ch. 14) But today, the honor goes to knowledge.
As Hilary Putnam once said, "It ain't obvious what's obvious." Or as I like to say, "One man's datum is another man's theory."
But is it obvious that it ain't obvious what's obvious?
It looks as if we have a little self-referential puzzle going here. Does the Hilarian dictum apply to itself? An absence of the particular quantifier may be read as a tacit endorsement of the universal quantifier. Now if it is never obvious what is obvious, then we have self-reference and the Hilarian dictum by its own say-so is not obvious.
Is there a logical problem here? I don't think so. With no breach of logical consistency one can maintain that it is never obvious what is obvious, as long as one does not exempt one's very thesis. In this case the self-referentiality issues not in self-refutation but in self-vitiation. The Hilarian dictum is a self-weakening thesis. Over the years I have given many examples of this. (But I am now too lazy to dig them out of my vast archives.)
There is no logical problem, but there is a factual problem. Surely some propositions are obviously true. Having toked on a good cigar in its end game, when a cigar is at its most nasty and rasty, I am am feeling mighty fine long about now. My feeling of elation, just as such, taken in its phenomenological quiddity, under epoche of all transcendent positings -- this quale is obvious if anything is.
So let us modify the Hilarian dictum to bring it in line with the truth.
In philosophy, appeals to what is obvious, or self-evident, or plain to gesundes Menschenverstand, et cetera und so weiter are usually unavailing for purposes of convincing one's interlocutor.
And yet we must take some things as given and non-negotiable. Welcome to the human epistemic predicament.
Some opponents of the death penalty oppose it on the ground that one can never be certain whether the accused is guilty as charged. Some of these people are pro-choice. To them I say: Are you certain that the killing of the unborn is morally permissible? How can you be sure? How can you be sure that the right to life kicks in only at birth and not one minute before? What makes you think that a mere 'change of address,' a mere spatial translation from womb to crib, confers normative personhood and with it the right to life? Or is it being one minute older that confers normative personhood? What is the difference that makes a moral difference -- thereby justifying a difference in treatment -- between unborn human individuals and infant human individuals?
Suppose you accept the general moral prohibition against homicide. And suppose that you grant that there are legitimate exceptions to the general prohibition including one or more of the following: self-defense, just war, suicide, capital punishment. Are you certain that abortion is a legitimate exception? And if you allow abortion as a legitimate exception, why not also capital punishment?
After all, most of those found guilty of capital crimes actually are guilty and deserving of execution; but none of the unborn are guilty of anything.
My point,then, is that if you demand certainty of guilt before you will allow capital punishment, then you should demand certainty of the moral permissibility of abortion before you allow it. I should add that in many capital cases there is objective certainty of guilt (the miscreant confesses, the evidence is overwhelming, etc.); but no one can legitimately claim to be objectively certain that abortion is morally permissible.
There is much popular confusion concerning the topic of relativism. One fallacy I exposed earlier, namely, the mistake of thinking that Einstein's Theory of Relativity implies either moral relativism or relativism about truth. Even more widespread, perhaps, is the notion that one who opposes relativism about truth must be a dogmatist. But there are two distinctions here and they must not be confused. One is the distinction between relativism and nonrelativism, and the other is the distinction between fallibilism and dogmatism. The first distinction has to do with the nature of truth, while the second pertains to the knowledge of truth.
In his magisterial Augustine of Hippo, Peter Brown writes of Augustine, "He wanted complete certainty on ultimate questions." (1st ed., p. 88) If you don't thrill to that line, you are no philosopher. Compare Edmund Husserl: "Ohne Gewissheit kann ich eben nicht leben." "I just can't live without certainty." Yet he managed to live for years after penning that line, and presumably without certainty.