Presentation on theme: "The Existence of God. CLASSICAL PROOFS Classical Arguments There are three ‘classical’ arguments for the existence of God: The cosmological argument."— Presentation transcript:
The Existence of God
Classical Arguments There are three ‘classical’ arguments for the existence of God: The cosmological argument The teleological argument The ontological argument
Cosmological Argument Premise 1: All motion we observe is derived motion; things that move have their momentum imparted by earlier moving things that moved them, which in turn were themselves moved by earlier moving things, etc. Premise 2: This process can’t stretch back infinitely. Conclusion: There must be an ‘unmoved mover’ that started the process. This is God.
Variant Premise 1: All events we observe are contingent (might not have happened) and caused by earlier contingent events, which in turn were caused by still earlier contingent events, etc. Premise 2: A causal chain, all of whose links are contingent, can’t stretch back infinitely. Conclusion: There must be a non-contingent (necessary) first cause. This is God.
The Idea The idea here is that contingent things require explanations. Because they could have not happened, we have to explain why they did happen. There can’t be an infinite chain of explanations that doesn’t “ground out” somewhere. Necessary things, since they must happen, require no explanation: there’s no other way for things to have gone. So a necessary thing must be the original source for all the contingent events.
Common Criticisms 1.God is claimed to have these properties (unmoved mover, necessary existence), but no evidence is offered. 2.An unmoved mover or a necessary being might not be God. The argument doesn’t tell you the unmoved mover loves humanity or even that it thinks at all. 3.There’s no logical reason that a chain of derived motion/ contingent causes can’t stretch back infinitely.
Paley’s Analogy “In crossing a heath, suppose I pitched my foot against a stone and were asked how the stone came to be there, I might possibly answer that for anything I knew to the contrary it had lain there forever; nor would it, perhaps, be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place. I should hardly think of the answer which I had before given, that for anything I knew the watch might have always been there…
Paley’s Analogy Yet why should not this answer serve for the watch as well as for the stone? Why is it not as admissible in the second case as in the first? For this reason, and for no other, namely, that when we come to inspect the watch, we perceive— what we could not discover in the stone—that its several parts are framed and put together for a purpose.”
The Teleological Argument Premise 1. All around the world we see complex aspects of nature that serve a valuable purpose, and could not serve that purpose if they were any different. Example: The human eye is complex, allows us to spatially locate ourselves and other objects in our environment almost instantaneously, and could not function if any of its many interacting parts were different from how they are.
The Teleological Argument Premise 2: It is impossible or at least extraordinarily unlikely that complex purpose- serving adaptations could come about by “blind” unguided natural processes. Conclusion: Therefore, structures like the human eye were consciously designed by an intelligent creator. This intelligent being is God.
Hume’s Criticisms 1.Even if the argument proves a designer’s existence, it cannot prove God’s existence. God is all good, but there are complex purposeful adaptations in nature that do nothing but cause pain and suffering (e.g. AIDS virus). The designer is not all good. 2.Similarly, God is all powerful/ intelligent. But poor design (human sinus) shows that the designer is either incapable or incompetent.
Hume’s Criticisms 3. Nothing in the design argument rules out the universe having multiple, distinct designers. 4. Accepting the conclusion of the argument (the existence of a designer/ God) presents us with a regress. For God presumably has complex parts that work together to serve a valuable purpose. So God too must have been designed by another designer. And that designer too must have been designed, etc.
Darwin The teleological argument suffered most at the hands of Darwin, who showed how complex adaptations could arise by natural means, via a process of random generation and natural selection. Random mutations generate new anatomical structures; if they are beneficial, the genes that produce them proliferate; if they are harmful, a quick death removes them from the gene pool.
The Fine-Tuning Argument A contemporary version of the teleological argument is the “fine-tuning” argument. Premise 1: There are fundamental physical parameters, like the strength of gravity, the strength of electromagnetism, and the strength of the strong nuclear force. If these were only slightly different, life could not possibly exist.
The Fine-Tuning Argument Premise 2: It is highly unlikely that a universe with randomly-selected values for these parameters would support life. Conclusion: The parameter values were selected by an intelligent being that desired life in the universe.
Criticisms The Anthropic Principle: In order for life to observe the fine-tuning of the universe, the universe has to be fine-tuned. We’re not in a randomly selected universe, we’re in a randomly selected fine-tuned universe. Most of the universe contains no life, and complex life on Earth has existed for only a very short period of time. If the creator wanted life, this is a funny way to make it!
The Ontological Argument 1.God is, by definition, the greatest being conceivable. 2.Things that exist are greater than things that don’t exist. 3.If God does not exist, then we can conceive of a greater being: something just like God, but that does exist. 4.But that’s a contradiction with (1). Therefore, God exists.
Criticism: The Perfect Island 1.Define Paradise = the greatest island conceivable. 2.Islands that exist are greater than islands that don’t exist. 3.If Paradise does not exist, then we can conceive of a greater island: something just like Paradise, but that does exist. 4.But that’s a contradiction with (1). Therefore, Paradise exists.
Criticism: Hume on A Priority The ontological argument does not rely on any assumptions about how things actually are. Therefore if it’s a good argument, then the conclusion is true, no matter how things are. Therefore, it should be impossible to imagine the conclusion being false. But it’s trivially easy to imagine our world existing, but with no God in it. So the argument must go wrong somewhere.
Criticism: Kant on Existence Kant’s famous response to the ontological argument was to claim that “existence is not a predicate.” The main idea was that imagining God and imagining something-just-like-God- that-existed was the same thing. To imagine a thing is to imagine its existence. Therefore premise (3) is wrong: even if God does not exist, we can’t imagine anything greater than God.
Types of Reasons There is a variety of types of reasons in the world: Moral reasons: You ought not to kill babies for fun, because it is morally wrong to do so. Prudential reasons: You ought not to cut off your fingers, because it is not in your best interests. Epistemic reasons: You ought not to believe that smoking is healthy, because the evidence says otherwise.
Reasons for Belief Clearly most of our reasons for our beliefs are epistemic reasons. Sometimes we hold beliefs for non-epistemic reasons: I might believe my wife is faithful, despite all the evidence to the contrary, because it makes me feel good. Or I might believe that different races of people were equally smart, even in the face of compelling counterevidence, out of a moral conviction regarding equality.
Evidentialism However, we largely regard holding beliefs for non-epistemic reasons to be irrational. I should not (rationally) believe my wife is faithful, if the evidence says otherwise. And even if it flies in the face of my moral convictions, I should (rationally) believe what the evidence suggests to be true, even if it’s morally wrong to do so. Evidentialism is the philosophical doctrine that only epistemic reasons (evidence) are relevant to what we should rationally believe.
Prudential Reasons for Believing in God There is, however, an interesting argument put forth by Blaise Pascal, that we should believe in God no matter what the evidence says, regardless of what epistemic reasons we have. We have an overwhelming prudential reason to believe in God’s existence, one that trumps any epistemic reasons we might have. Evidentialism is false, if Pascal is right.
Blaise Pascal (1623-1662)
Blaise Pascal Pascal was a mathematician, physicist, and philosopher. Among his many achievements, he invented the mechanical calculator, discovered Pascal’s triangle, and was one of the early pioneers in probability theory and decision theory.
No Epistemic Reasons for God’s Existence “If there is a God, He is infinitely incomprehensible, since, having neither parts nor limits, He has no affinity with us. We are incapable, therefore, of knowing either what He is or if He is. That being so, who will dare undertake to decide this question? Not we, who have no affinity with Him. Who then can blame the Christians for not being able to give reasons for their belief, professing as they do a religion which they cannot explain by reason.”
Decision Theory Decision theory is the mathematical discipline devoted to calculating the prudentially best course of action. While Pascal believes there cannot be an epistemic reason for belief in God, he thinks decision theory can show us there is an excellent prudential reason for such belief.
Problem Specification Solving a decision problem begins with a problem specification, breaking down the problem into three components: 1.Acts: the various (relevant) actions you can take in the situation. 2.States: the different ways that things might turn out, and the probabilities of each. 3.Outcomes: What results from the various acts in the different states.
Example For example, consider a simple decision problem involved in betting on a sports team: 1.Acts: Bet on the Dragons, bet on the Cherry blossoms. 2.States: Dragons win (1-to-4 odds), Cherry Blossoms win. 3.Outcomes: +$500 for successful bet on Dragons, +$300 for successful bet on Cherry Blossoms, -$200 for any lost bet.
Decision Tables Decisions, after being analyzed by a problem specification, can be summarized in a decision table, with the Acts on the left, the States on the top, and the corresponding Outcomes (plus the probabilities of those Outcomes) for each Act, State pair in their appropriate locations.
Example Table: Dragons WinCherry Blossoms Win I bet on Dragons +$500 0.2 -$200 0.8 I bet on Cherry Blossoms -$200 0.2 +$300 0.8
Expected Value The expected value of an act is the weighted average of the values of the outcomes of the act. The outcomes of betting on the Dragons, for example, are +$500 and -$300. How do we weight them? By the probability that we’ll receive each value. If the Dragons have a 20% chance of winning, the EV of a bet on them is: $500 x 20% + -$300 x 80% = -$140
Maximize Expected Value According to decision theory, the act you should (prudentially) choose– the one that’s in your best interest– is the act that maximizes expected value. One way of justifying this is that the Law of Large Numbers says that if you bet on games exactly like this a large number of times, on average you will receive the expected value of each bet.
Pascal’s Wager Here’s the decision problem as Pascal sees it: Acts: Either you can believe that God exists, or you can not believe that God exists. States: Either God does in fact exist or He does not. (Ignore the probabilities for now.)
Outcomes 1.You believe in God, and He exists: an “eternity of life and happiness” in heaven. 2.You believe in God, and He does not exist: some wasted time in church. 3.You don’t believe in God, and He exists: no heaven (maybe hell?). 4.You don’t believe in God, and He does not exist: free time on Sundays (Saturdays).
Decision Table God existsGod does not exist Believe in God+∞-finite amt Don’t believe in God +finite amt
No Probabilities, Numbers Needed There are no probabilities or specific numbers indicated in this decision specification. Why? It doesn’t matter: The maximum expected value of “don’t believe in God” is always going to be identical to the maximum outcome, which is always finite.
The Wager The minimum expected value of “believe in God” is always going to be +infinity, provided that there is a non-zero probability that God exists. Since obviously there’s a non-zero probability of God’s existence, and +infinity is greater than any finite number (the max expected value of disbelief), Pascal says you should always believe in God.
The Other Gods Problem One common response to Pascal’s wager has been that it can’t be correct, because it equally recommends a belief in any other deity (that promises an infinite reward). As such, it recommends belief in no deity at all, because there’s no way of choosing.
Zeus God existsGod does not exist Believe in Zeus+∞-finite amt Don’t believe in Zeus +finite amt
Criticisms Other common criticisms: The wager assumes doxastic voluntarism: that our beliefs are under our control. It assumes God wants us to believe regardless of the evidence. It assumes that it’s possible for prudential reasons to rationally justify a belief. (Assumes that evidentialism is false.)
THE WILL TO BELIEVE
William James (1842-1910)
William James William James was an introspectionist psychologist and an American pragmatist philosopher. (Pragmatism, remember, was founded by Pierce.) James also famously argued against evidentialism, and even quotes Pascal: “Le cœur a ses raisons, que la raison ne connaît point.” The heart has reasons that reason never knows.
Hypotheses and Options James starts out by introducing some terminology: Hypothesis: something we can potentially believe. Option: a choice between two hypotheses.
Properties of Options Living or dead: a living option is one where you can seriously entertain the possibility of believing either hypothesis. Forced or avoidable: an avoidable option is one where you can choose not to believe either hypothesis. Momentous or trivial: a trivial option is one where accepting either of the hypotheses doesn’t affect you very much.
Genuine Options James calls an option genuine if it is forced, living, and momentous. You cannot avoid the choice, both hypotheses appeal to you somewhat, and your decision matters a lot.
Response to Doxastic Voluntarism James concedes that what we believe is not fully under the control of our wills. However, he thinks this has to do with the living vs. dead distinction. If an option is dead, and we can only seriously entertain one of its hypotheses, then we cannot by force of will entertain the other. But belief in either hypothesis of a live option is a matter of will.
Principles of Belief James says there are two principles we try to satisfy when forming beliefs: 1.Believe the truth. 2.Don’t believe false things. We can satisfy (2) by believing as few things as possible, and satisfy (1) by believing as many. It is a balancing act to satisfy both at once.
Most Speculative Issues are Trivial Most speculative issues, according to James, are trivial: it doesn’t matter to our lives, James says whether we: Have a theory of the nature of X-rays. Believe in dualism, that the mind is a different substance than matter. Believe that conscious states can have causal effects.
Warranted Skepticism Because the issues are trivial, James thinks that an aloof skepticism is warranted. We should simply suspend belief in, say, dualism vs. materialism, because it doesn’t matter. That doesn’t mean we shouldn’t keep investigating the issue– it’s just that there’s no particular reason for commitment either way.
Warranted Skepticism “Wherever the option between losing truth and gaining it is not momentous, we can throw the chance of gaining truth away, and at any rate save ourselves from any chance of believing falsehood, by not making up our minds at all till objective evidence has come.”
The Scientific Method On James’ view, scientific matters should be conducted in ways that avoid error, at the cost of being overly cautious– because getting the truth right is not that important. Science has thus codified a method that is overly cautious– and that’s a good thing. However, it is wrong to then apply that method to momentous options. There, avoiding error at all costs is inappropriate.
Faith Creates Facts (Sometimes) James says there are cases “where faith in a fact, based on need of the fact, can create the fact.” An example he gives is friendship. If I don’t believe you like me, because I don’t have any evidence that you do, you’re unlikely to like me. Whereas if I believe that you like me, on faith, then it is more likely to be true that you like me.
Religion What about religion? First, James says, religion presents us with a momentous choice For some it might not be living, but he has nothing to say to those people. It’s forced in the sense that to accept religion or not accept it exhausts the logical options. So whether to accept religion is a genuine option.
Faith Creates Evidence (Sometimes) Clearly, believing in God doesn’t make God exist (although later in life, James came to believe this). However, James thinks only a belief in God opens the door for evidence of God’s existence. If we are too skeptical and scientific, God “won’t like us” and then we will never get the evidence of His existence.
Conclusion James identifies two specific circumstances where he thinks evidentialism fails: self-fulfilling beliefs, where having the belief makes it true/ more likely to be true, and beliefs where having them makes it more likely that you will get evidence for them (if such evidence exists).
Conclusion When the issues are trivial, we might still suspend belief, to avoid falsehood. But when they are momentous, like with religion, suspending belief can be catastrophic. Thus rationality recommends belief in religion even when the evidence does not support such belief.
Criticism The obvious problems with this approach are that James doesn’t really explain how belief in religion is required for evidence for religion, he just gives us a friendship metaphor. Second, James doesn’t describe any of the evidence he’s received for God’s existence after willing to believe in Him.
Criticism Third, the argument again seems too powerful: if contradictory things all have the property (belief in them increases likelihood of evidence), then we’re led to believe contradictions. For example, if I’m more likely to get evidence of Zeus from believing in Zeus, and more likely to get evidence of (the JC) God from believing in God, should I believe in both?
HUME ON MIRACLES
Hume on Miracles As I said last time, Hume’s Enquiry concerning Human Understanding is mostly just a shortened, beautifully written version of Part I “Of the Understanding” of his earlier A Treatise of Human Nature. However, there is one section, Section X, of the Enquiry that is totally new: “Of Miracles.” Hume added this mostly to rile up people and get them to read and discuss his work.
Degrees of Confirmation Different claims are confirmed by out experience in differing degrees: Sometimes they are always confirmed: “An ice cube melts after an hour in the sun.” Sometimes they are sometimes confirmed: “Birds fly.” Sometimes they are rarely confirmed: “Thai food is bland.”
Wisdom Hume says: “A wise man, therefore, proportions his belief to the evidence.” You believe things “more” when there’s more evidence for them.
Example: Testimony For example, suppose you have three friends: Butter, Candice, and Dianne: Butter tells the truth very rarely. Candice tells the truth about half the time. And Dianne usually tells the truth. If Dianne tells you something, and Butter tells you the opposite, you should believe Dianne.
Mixed Evidence Sometimes, we have “mixed” evidence– not just testimony, but testimony AND observation AND theoretical prediction AND… For example, suppose while you’re walking along with a friend, you get robbed. How old was the guy who robbed you?
Example: Mixed Evidence Testimony: your friend was with you and he thought the guy was between 38 and 42. Observation: to you he seemed younger, between 30 and 34. Theoretical Prediction: the police have a suspect– if the suspect is the robber, he was 39. If you have to guess the robber’s age, you need to use all the available evidence.
Karl von Frisch Karl von Frisch was a Nobel Prize winning scientist who studied bees, and bee communication.
Laboratory Studies… “If we use excessively elaborate apparatus to examine simple natural phenomena Nature herself may escape us. This is what happened some forty-five years ago when a distinguished scientist, studying the colour sense of animals in his laboratory, arrived at the definite and apparently well-established conclusion that bees were colour-blind…”
vs. Field Work “…It was this occasion which first caused me to embark on a close study of their way of life; for once one got to know, through work in the field, something about the reaction of bees to the brilliant colour of flowers, it was easier to believe that a scientist had come to false conclusion than that nature had made an absurd mistake.”
Novel Testimony Suppose now that we get testimony concerning something we have never experienced. Hume imagines someone from the equatorial regions being told about frost, and snow, and ice. They have never experienced anything like that before.
Hume thinks this person would have reason to disbelieve stories about a white powder that fell from the sky, covered everything by several inches, and then turned to water and went away. It’s not that they should believe the stories are not true, just that they don’t have to believe they are true. We need more evidence.
But suppose someone tells us an even stranger story. It’s like the snow-story, in that we’ve never experienced anything like it before. But it’s even stranger, because we have always experienced the opposite before.
Miracles For Hume, this is the definition of a miracle. A miracle is a violation of the laws of nature. Every event or process in the world conforms to the laws of nature (for example, the laws of physics like the law of gravity)– except, if there are any, miracles.
Example There are about 100 billion people who have lived and died in the history of humanity (and there are 7 billion more who are alive now). As far as we know, none of the 100 billion people who have ever died and were dead for four days, later came back to life. It’s a law of nature that when you die, that’s the end, there’s no more.
Lazarus Although there is testimony, in at least one religious book– the Christian bible– that such an event occurred at least once in history, when Jesus raised Lazarus from the dead, after he had been dead for four days.
What Should We Believe? According to Hume, we should be wise and apportion our belief to the evidence. Since on the one hand we have 100 billion people who died and never came back, and on the other hand we have an old legend from a book intended to make people believe its religious views, it’s most probable that the raising of Lazarus never happened.
Hume on Miracles “No testimony is sufficient to establish a miracle, unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavors to establish.”
Seeing and Believing So, for example, Hume would even say that if you saw someone die and come back to life, you should not believe that it really happened. Because it’s always possible that what you saw was a trick, or the person was never really dead, or you were on drugs or… Since none of those suppositions are miraculous, you should believe them instead of believing in the miracle. They’re more likely than a violation of nature’s laws.
Problems with Testimony It’s of course possible that the number of independent witnesses to a miracle could outnumber the times we have seen a certain law of nature confirmed. If that were so, Hume would have to accept the miraculous testimony, provided the witnesses were reliable enough. So Hume spends some time arguing that testimony about miracles is not very reliable.
Problems with Testimony Hume gives several reasons why testimony about miracles is problematic: 1.There has never been a well-established, independently corroborated miracle. 2.People have reasons to lie about miracles, to convince others to believe their religion. 3.We have lots of evidence of fake miracles and forgeries (e.g. the shroud of Turin).
Problems with Testimony Finally, Hume argues, if there is at most one true religion (and maybe none) then all of the other religious holy books must contain false testimony of miracles. Therefore, most testimony of miracles is false. So upon receiving testimony of a miracle, the most likely supposition is that it is false.
Summary There are interesting epistemic issues surrounding God and religion. (An interesting one we didn’t cover: if God knows what will happen in the future, does that mean I’m not free to choose what to do?) Some philosophers have argued against evidentialism and for the idea that belief in God can be rational, even if there’s no evidence for God’s existence.
Summary Other serious evidentialists, like Hume, have argued not only that evidence is required for a belief in anything, but that in the case of religion, some putative evidence frequently cited in its favor (testimony of miracles) cannot in principle provide evidence for religion.
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