Purpose and the Universe

On Sunday I was privileged to give the keynote address at the American Humanist Association annual conference. Even better, people actually showed up for the talk, which for a Sunday morning event is pretty sweet.

The talks were live-streamed, and naturally some enterprising young humanist (thanks Carl Wong!) captured them and put them on YouTube. So here is mine; don’t forget to check out the others (or directly from the AHA site).

My talk was similar to ones I had given before at TAM and at Skepticon, but about half of it was new. The general idea is the relationship between everyday human concerns of meaning and morality and the underlying laws of physics. For this one, I used the framing device of “purpose” — what is it, and where does it come from? The universe itself doesn’t have a purpose, nor is there one inherent in the fundamental laws of physics. But teleology (movement toward a goal) can plausibly be a useful concept when we invent the best description of higher-level phenomena, and at the human level there are purposes we can create for ourselves. All part of the “poetic naturalism” bandwagon I hope to get launched, although I didn’t specifically use that term.

My actual slides aren’t always crystal clear from the above view, so I also put them on Slideshare. Enjoy!

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86 Responses to Purpose and the Universe

  1. Meh says:


    Atheism is in fact the belief that the god described by religion(S), does not exist. Higher order lifeforms that have evolved past us by 1 million years, sure. gods from fairy tales, no. The point you’re missing is that it’s a belief.,

    “but then that’s about as useful as saying Jupiter does not exist on Mt. Olympus, in which case who cares?” a statement which applies to all religions, atheism, and agnosticism. The issue that arises is the mindset of an organization that convinces its followers to burn people at the stake because they are witches. And of course, any dimwitted moron knows that religions don’t do that in 1st world countries anymore; but they still follow that mindset of letting our civilization, laws, and culture be highly influenced by belief rather than observable fact. And that’s the scariest problem ever.

  2. Tom Clark says:

    “All part of the “poetic naturalism” bandwagon I hope to get launched…”

    Terrific, look forward to the launch. You’ll find lots of support from religious, ecstatic and spiritual naturalists (sorry for the cognitive dissonance!) who don’t impute purpose to the cosmos and find that living in a wild unsupervised universe is an existential breath of fresh air.

  3. Doc C says:

    This point of view is just another arbitrary story of the truth that guides us in how we conduct our lives. There is no objective truth available for that goal, and in fact most of the values of this kind of humanism correspond isomorphically with many religious faiths and traditions, except they are attributed to “natural truth” instead of divine truth. You claim that my purpose in life is all about me, as long as it is compatible with the way the universe works. Yet, if I come to believe that my purpose in life is the destruction of human civilization because it destroys so many other life forms on earth, why is that not compatible from the way the universe operates? If I can convince enough people to follow my example, and actually accomplish my goal, killing the last of us in on final Jamestown event, why is that not also compatible with the way the universe operates. According to your scheme, Evolution has no favorites, nor goals, and no values are any more intrinsically valuable than any others, as long as they arise from what we call natural laws, which you claim are purposeless. This is a slippery slope. It does not lead us to a better way to conduct our lives, but rather opens us up to nihilistic chaos.

    I think rather than claim there are no absolute values, we need to come to an agreement about what those absolute values should be. Science can certainly help with that, but even science is helpless without imagination, and so we must be open to our artistic and religious imaginations when we explore the absolutes that we as a civilization need.

  4. Mickey Mortimer says:

    James Cross wrote- “Is there really a way to measure “interestingness”?”

    Well no, it’s subjective, which is why I qualified my reply with “given what most people would view as “interesting””. But given that caveat, I think it’s undeniable having more accessable planets/civilizations/universes would increase the amount of stuff to be interested in, by virtually anyone. Interested in art? A billion cultures to spend your time on instead of however many Earth contains. Interested in biology? A billion biospheres instead of one. Worried no one will have time to appreciate and integrate a billion examples of something? In this universe, people are immortal and don’t require sleep. Or for your example of interplanetary warfare being less interesting, how about a universe where organisms from different evolutionary histories can’t hurt each other? Problem solved. When imagining different universes, literally any problem you could raise could be solved, so no matter how you personally define interestingness, a universe could be imagined with more of it. I think you simply lack imagination as to how things could be different.

    Regarding your game example, games evolve to be more fair and entertaining since versions coexist with each other and are selected by a limited set of people. This is utterly different than the situation for “stars, galaxies, life, and intelligence”. You would need some process or entity to sort civilizations based on interestingness, and that doesn’t seem to exist. At least not for Earth.

    Finally, as I don’t believe in objective morality, I don’t see any choice as “more moral” or “better” than any other. At least not with more authority than I can say a food is more tasty or an activity more fun. And again you would need some sorting mechanism to prefer interestingness even if the universe did have objective morality.

  5. James Cross says:

    “I think you simply lack imagination as to how things could be different.”

    More is not necessarily better or more interesting. A limited life may be more interesting than an immortal one. A life with pain, suffering, and loss more interesting than one with none of those things.

    There was an old Twilight Zone where the criminal gets killed and winds up in a place when everything is wonderful. He always wins at the roulette table. Woman are waiting for him at every turn. He thinks he is in Heaven. Time passes and he begins to grow bored and frustrated. Everything is too easy. Finally his “host” informs him that he is not in Heaven. He is in Hell.

  6. Jarrod CL says:

    “It does not lead us to a better way to conduct our lives, but rather opens us up to nihilistic chaos. ”

    By the same token, developing a universal agreement on what the absolute values is, I would argue, outside of our ability at this point. Any absolutes we defined would be fundamentally flawed, simply because we’re really not that good at some of the essential skills needed to determine absolute values.

    For one, we’d need to work out what those absolute values point to, as they should not be an end in themselves. Values as ends in themselves lead to stupid, unthinking behaviour. Assuming we all agree on what the values should create for humanity (hah!), let’s say “happiness”, and that we understand and reach a concord on what that means, then we need to think really hard about how the values will achieve that. Given their status of absolutes…well, we’d better be right, or we’re going to have some heinous wars.

    The next part is best summed up by “the road to hell is paved with good intentions”. That is, we don’t, as individuals, even know what is good for ourselves, let alone be able to reach some kind of universal agreement. We’re just not there yet. We might be, one day, but for now….I am in a position where absolute values at either end (of the knowingly human inspired, or the unknowingly human inspired) are more dangerous than the middle road of admitting there are no values except what we make, and to expect those to royally screw us over in some unforseen way. We’re children, at this point.

  7. Roland Chiasson says:

    @Frankl: all that bullcrap about absence of evidence and evidence of absence is -sad to say for your sakes- T R U E … live with it … anyhoo one quick question: what does that possibly-yet-to-be-found-god of yours does? … what is its beef against kids that it kills them randomly thru intense torture -famine-? … some fuckin* god if you ax me bubba … anyone on the whole Earth -that is a lot of folks- who believe in anything when there are ways to go the extra mile and actually know/learn about most things physical those persons who choose to sit down and daydream about the future instead of living said future are just plain lazy or incapable of thoughts -not actually their faults for their ‘wrong programming’- … tough shit for them and sad yes … but them/you being sickly mentally deficient religiously/spiritualy is a fact of life … even newton -Isaac hisself- was religiously demented yet still producing … at that point it is a question of how useful to others the sickos are and the intensity of their delusions … that is as clinical as I can get … hope it helps … do not cry, being demented is not that bad/scary after a while … soon that bad dream will go away but the first step is not to look/shy away next time your other voice/self asks a question … shirley you will not try to entrap yourself to the point of hurting the whole where/in which you live… if yes then do not go in public places and try to kill yourself quietly …

  8. FrankL says:

    Meh – When you boil it down, the only motivator is belief, an unexamined value system which provides purpose. There is *absolutely* no rational system of values, there is only behavior given those set of values which may or may not be rational and informed. There is only one value that any evolutionary unit holds and that is propagation. People can agree on the unit, but disagree on tactics, that’s solvable. They can disagree on the unit, and can, through discussion, realize that one or both are wrong, that’s solvable, but if they fundamentally disagree on the evolutionary unit, the only solution is competition, perhaps to the point of war. I’m fuzzy on my evolutionary unit. Celibate priests choose the church as the evolutionary unit, there’s also the gene, the individual, family, ideology, religion, political party, nation, species, the earth, the universe. Don’t come to me and declare that you have found a rational morality, I will ask for whom, for what evolutionary unit? Morality is a code of behavior more or less rationally derived from the fundamental value for a given evolutionary unit assuming its members are able to converse and agree upon something. It can be successfully shared by a number of different units, if it provides an advantage for each, but otherwise, without deception, forget it.

    If atheism is a rejection of the Gods of organized religions, then sure, I’m an atheist too, but I don’t think that’s the definition we are talking about. It seems that science-oriented atheists are people who can’t find a place for God in their equations. Why can’t we look at Sean’s “equation of everything that matters” and see it as a glimpse of God? Anyway, it’s a quantum equation, it deals in probabilities, not certainties. It’s like saying “I have examined the 12th eyelash on your left eye, and I see no face, therefore I conclude you have no face”, which is just arrogant.

    Roland – Atheists who reject God because he “allows” bad things to happen, are just rejecting the God of organized religion(s), invented to give security and purpose to desperate, mortal people. Desperate, mortal people are the motherlode for people who want to control everybody, and when religion is perverted to this purpose, you get what you pay for. Political parties and politicians are subject to the same perversion, they are really just organized religions under a different name. As an agnostic, I don’t demand that God fulfill my expectations, I am just curious about finding out what the hell he has in mind, if anything. We look back on those who wrote the Bible and say “nice try but….” and a few thousand years from now, people will be looking back on us and saying “nice try but…”. It’s arrogant to expect otherwise.

  9. Meh says:


    I agree with (or at least can accept it as rational and respectable ) everything you said. Except for your assumption that evolutionary units hold only 1 value, propagation. I think that’s absolutely wrong and can be proven in human behavior. We control our population; half of us do. It’s one of the few things that separates us from being just regular animals. That idea makes me think that you’re oversimplifying a very complex social process. But hey, doesn’t bother me. Still a good point, I just don’t think it applies to advanced lifeforms.

  10. vmarko says:

    @ Roland:

    “what does that possibly-yet-to-be-found-god of yours does? … what is its beef against kids that it kills them randomly thru intense torture -famine-?”

    Don’t you know the story about Adam and Eve? They wanted to learn the knowledge of good and evil. So God fulfilled their wish by casting them out of the Heaven and into a mortal world, where He would not interfere with their sufferings. Through suffering, they would learn the knowledge of good and evil.

    Figuratively speaking, all people are descendants of Adam and Eve. Literally speaking, all people have the capability of distinguishing between good and evil, unlike other animals. So when a tsunami hits and kills several thousands of people, or when the Inquisition tortures and kills people randomly, or when the US drops a nuclear bomb in Japan, or when a tornado wipes out a town full of people, or when your child dies of cancer or hunger (hopefully not) — that is god’s lesson about the difference between good and evil. We “wanted to know” — so now we are learning! 😉

    On a more serious note — the concept of “god” does not “live” in the material world, but in the world of human relations — humans are social animals, and god operates only at that level (providing solace and peace through interactions with other people), rather than by violating laws of physics. That is, if you believe in god.

    If you don’t believe in god, then when a child dies by a tsunami, the mother might find some consolation for her pain in Sean’s subtitle “in truth, only atoms and the void”, because that’s all that exists for an atheist.

    Even if you consider such concepts — god, life after death, etc. — as just a “delusion”, it can be a very useful one, if only as a placebo. This is understood by most humans on the planet, except by a minority that consider themselves “more rational and scientific” than others. Talk about irony…

    HTH, 🙂

  11. MKS says:


    what a joy it must be to be able to express your unique culture to so many people :3

  12. FrankL says:

    Meh – do you have an example of an evolutionary unit having a value other than propagation, so I can get an idea of what you are talking about. I think the complexity is in the definition, the understanding, of the evolutionary unit. Any evolutionary unit that does not propagate ceases to exist.

  13. Jack M says:

    Thank you very much Sean for a great perspective. I love the idea that the fundamental science of our everyday lives is known and complete.

    I have a question however. I gather that you differ from Alex Rosenberg’s nice nihilism perspective. Alex observes that our moral feelings evolved to solve a survival problem and that there is no basis for asserting any objective truth value to them.

    It seemed as though, near the end of your talk, you were inferring that gay marriage “ought” to be permitted from the fact that there is no law of nature prohibiting it. I share your moral feelings in this regard, but are you asserting some objective truth value to that moral feeling?

    I would be very grateful if you found a moment to reply.

  14. James Cross says:

    Frankl, Jack M

    I think science suggests certain moral values but does not impose them. It suggests that actions that expand possibilities and enhance life are better than those that don’t but this is not objective truth nor can it be said to always to be true. Ultimately humans create their morality both as individuals and groups.

  15. vmarko says:

    @ Jack:

    “It seemed as though, near the end of your talk, you were inferring that gay marriage “ought” to be permitted from the fact that there is no law of nature prohibiting it.”

    I don’t remember what Sean said, but the above inference is very stupid — by the same logic, murder ought to be permitted, since there is no law of nature prohibiting it.

    Laws of nature do not fix moral rules. While some of the rules were established based on objective evolutionary consequences (like incest and gay marriage), other rules (like “love your enemy”) go against any evolutionary preferred behaviour.

    @ James:

    “I think science suggests certain moral values but does not impose them. It suggests that actions that expand possibilities and enhance life are better than those that don’t but this is not objective truth nor can it be said to always to be true.”

    What do you mean by “enhance life”? Promiscuity could be considered as a way of “enhancing life”, though probably it is an overkill example. 🙂

    “Ultimately humans create their morality both as individuals and groups.”

    Agreed. 🙂

    Best, 🙂

  16. Meh says:


    Yep, that’s where the disconnect is. It sounds like you are classifying an evolutionary ‘unit’ as an entire species. I am classifying an evolutionary unit as an individual unit. You are using it as a broad generalized term. In which case, sure, they cease to exist. But maybe existence is not a priority or even understood in some cases. My specific example was that a lot of people have various values other than propagation because they realize that they don’t need to propagate for the rest of the species to survive and thrive. Monks and priests are examples, Stephen Hawking is an example, even Kate Upton’s rather buoyant self. I think people are very different from an oversimplified evolutionary unit. Some people can freak out about having babies leaving others to worry about how to harness the power of nature and others to worry about extending life by learning more and more about biology and others to worry about how to make the worlds best dildo design to date. I would say that most evolutionary units (in the generalized meaning) don’t even understand the concept of ceasing to exist, which is why they become extinct. They’re values are likely more simplistic; hungry, tired, hurting, frightened. So to me, using propagation as a single value for any and all evolutionary units to base their thoughts and beliefs around, is not true. In some instances it’s too complicated, in others it’s to simplified, but it’s not accurate/true either way.

  17. Roland Chiasson says:

    attention all earthlings!!! next mofo who mentions any god(s), possibility of god(s) gets detention … there I said it … the closest thing to any deity you will/can/could ever experience is -and that is a lesser god at that- is perfection that you can live …. a couple of Carroll’s presentations I just saw were just that and you, limited intellects, try to disssect it like scavengers to insert NOTHING to it in it for it … just try to grade one of his performances, that is all you can get from what he does … that will position you … knowing one’s place and strenght is the flow you are writing about … it cannot be dissected it is to be used and fly … I pity you all yet I cannot help you … sowwy …

  18. FrankL says:

    Meh – No, I really mean it when I say the definition of the evolutionary unit is where the complexity lies. “Entire species” is too simplistic.

    Step outside of the situation, as a scientist, and ask “why does the human species continually generate individual dead ends, monks, priests, gays, teen suicides, etc.?”. A corollary of evolution is that any trait that is present in numbers is (or recently was) an evolutionarily positive trait, or is (or recently was) inextricably associated with an evolutionarily positive trait. “Evolutionarily positive” means “enhances propagation”, period. So we have to conclude that the significant occurrence of individual reproductive dead ends is evolutionarily positive somehow, for some unit. No values attached, here. You can draw the same conclusion about the significant number of serial killers and rapists, and lack of significant numbers of people who spend their lives hopping on one foot while reciting the phonebook backwards.

    “a lot of people have various values other than propagation because they realize that they don’t need to propagate for the rest of the species to survive and thrive. Monks and priests are examples, Stephen Hawking is an example, even Kate Upton’s rather buoyant self.”

    Take monks and priests – the way to analyze this is to set up a thought-experiment. If you have two tribes or societies competing for the same resources, and their power is not so much determined by sheer numbers, then the society that generates an organizing force (e.g. a religion) with members who devote their energies to that organizing force rather than raise children will tend to succeed against a society that does not, all other things being equal. The reproductive members of that society are advantaged by generating some monks and priests. On the other hand, if power is in sheer numbers, non-reproductive individuals will be a drain on the society and put it at a disadvantage. Individuals can express different values, but when they conflict with the single propagation value, they are not rational. The tribe unit serves the reproductive unit and vice versa. In a situation where having more than two adults devoted to the success of children, gay members of a family may offer a reproductive advantage for that family. Stigmatizing gays and thereby forcing them into the life of a monk may offer a reproductive advantage to the tribe through the organizing force of religion. Religions as an organizing force rather than political ideologies may have an advantage for a disorganized society, for an organized society, political ideologies may replace religions. There are no various values, there is propagation, and everything else is tactics. Conservativism and progressivism are survival tactics, not values. Conserve too much, you don’t adapt (progress). Adapt too much, throwing away “old” traits, and you are subject to extinction by uncommon events. Don’t take this paragraph as my revealed truth, I’m just speculating. Stephen Hawking is not a good example, he is the way he is by fate, not choice. I don’t get the Kate Upton reference.

    Jack Cross and Doc C – Science suggests nothing. To suggest is to appeal to a value and true science is totally value-free. The only core value of an evolutionary unit is propagation, all other “values” are actually tactics. And to talk about what absolutes “We as a civilization” need, as Tonto said to the Lone Ranger when they were surrounded by hostile indians, “what you mean ‘we’, white man?” Any absolute that disadvantages a rational reproductive unit will be rejected by that unit and it will only conform under coercion. For some (e.g. rapists, murderers), my values make me happy to see them coerced, others not so much. The “absolutes” you talk about will be tactics, and I worry about “absolute tactics” in the face of a changing environment. Too conservative for me.

  19. Ryan Ashton says:

    Dr. Carroll,

    I enjoyed your talk and, like many in your audience, I find you to be an eloquent and entertaining speaker. I would like to comment on your reply to the final question about William Lane Craig’s Kalam Cosmological Argument.

    You say the first premise in the argument–everything that begins to exist must have a cause of its existence–is easily refuted. You go on to “refute” the premise by simply saying it might be wrong. I find this peculiar, though, because a refutation is to demonstrate that something is wrong, not just to doubt that it is true. For example, if Smith claims that all men are mortal, Jones does not refute this claim by asserting that all men may not be mortal. Certainly, Jones can choose to withhold belief in the mortality of men, but this only amounts to a stance of personal incredulity. A refutation, typically, is something much stronger: a refutation shows that a proposition is false. To demonstrate that the proposition all men are mortal is false, Jones would either have to produce a counterexample (e.g., an instance of a man who is immortal) or reduce the proposition to absurdity (e.g., show that the proposition is inherently contradictory, like the concept of a round square). Absent this kind of response, Jones has fallen short of refuting the proposition.

    As best as I can make out, your response to Dr. Craig is parallel to that of Jones’ response. You did not produce an example of a contingent entity springing into existence uncaused, nor did you reduce the proposition that everything that begins to exist has a cause to absurdity. Now, you did reject the principle of sufficient reason (PSR) at the beginning of your talk which, if correct, would rid you of the burden of demonstrating the falsity of Craig’s first premise; but, such a move would also rid Craig of the burden of justifying the first premise of the Kalam. When you say to Craig regarding this premise, “How do you know?” you seem to invoke something like the PSR–namely, you wish to demand an explanation for a proposition. But, if something like the PSR does not hold, as you seem to suggest, then Craig simply has no burden to justify the premise. Both the proposition that everything that begins to exist has a cause and the negation of this proposition would have equal warrant if something like the PSR is not true.

    Conversely, if the PSR were accepted as true, then Craig’s premise would require some kind of demonstration of its falsity in order to be refuted. Much like the proposition that all men are mortal, the proposition that everything that begins to exist has a cause is inductively derived. After a great many observations of contingent entities coming into existence, the finding that each one has had a cause of its coming into existence gives one good inductive grounds for generalizing that all contingent entities must be caused. Inductive generalizations never deliver certainty, but illustrating this shortcoming of inductive generalizations by no means amounts to a “refutation” of any given inductively-derived proposition. For this reason, I suggest Craig’s Kalam Cosmological Argument survives your criticism of it.

  20. Sean Carroll says:

    Jack M– Not sure how you could get that inference; I said pretty much the opposite of that. From nature alone, we cannot judge anything at all about the morality of gay marriage. What I said was that we should base our judgments on reality, in which there is no such thing as the “natural” or “proper” notion of marriage. Once one accepts that, my bet is that most obstacles to gay marriage evaporate, but one still needs to make an argument one way or another.

    Ryan– I’m not demonstrating that Craig’s conclusion is false, only that his argument is faulty. He’s making an a priori claim in a realm where you need to be empirical. The fact that things may or may not have causes simply means we need to build models and test them against data, like any other good scientific question, rather than sitting in our armchairs and drawing sweeping conclusions about reality based on pure thought.

  21. James Cross says:


    Admittedly there is a certain amount of judgment in the term “enhance life”. Basically, however, I am thinking of things that allow more humans to live better and more productive lives. But the concept could also be extended to preserving other life. This would include such traditional things such as “thou shall not kill” , the Golden Rule, and perhaps a modern day commandment to preserve the ecosystem, which makes sense in itself but also makes sense for preserving future human possibilities.


    That is Jim, not Jack, Cross if you want to be less formal.

    I think science does suggest. Evolution is based as much on cooperation within species and human groups as it is on competition and destruction. In our present world, it is even more imperative that actions that destroy other humans or the ecosystem be reduced and replaced by cooperation and stewardship. The alternative is our destruction. Just a suggestion, mind you, not an absolute value. I am certain Nature couldn’t care less if we destroyed ourselves in an absolute sense.

  22. FrankL says:

    Sean – you said “we should base our judgments on reality, in which there is no such thing as the “natural” or “proper” notion of marriage. Once one accepts that, my bet is that most obstacles to gay marriage evaporate, but one still needs to make an argument one way or another.”

    What if we were talking about the right of serial killers to murder indiscriminately? A good defense of their rights would be that there is no “natural” or “proper” notion of why they should be denied that right. You can tell me that’s nonsense, but it’s not. It sounds like nonsense because you unconsciously assume (and correctly) that we share the same values (or propagation tactics, actually).

    Gay marriage is a political football, based on the premise, (accepted by both sides) that the duly elected government has a right to distribute taxpayer money to individuals in a discriminatory way based on a government-defined marriage status. If both sides compromised and agreed that the government had no right to discriminate in any way, that it should be “marriage blind”, and that benefits accrued to any individual that the beneficiary directed, (their pet cat, for that matter), then the issue would evaporate. That won’t happen, though. Political parties are devoted to propagation, and that means to the acquisition of political power. For the republicans to accept your idea would disadvantage them, much as if the democrats accepted that there is no “natural” or “proper” notion of the right to government subsidized healthcare, it would disadvantage them. There is no “natural” or “proper” notion that serial killers should be actively discouraged, but I think both parties would find that that notion fits well with their tactics for the acquisition of power, and so that idea has traction.

    In a situation where sheer numbers are vital to a tribe or society’s survival, gay marriage would be tactically discouraged, and rightly so. In a situation where sheer numbers are counter productive, the opposite tactic would be favored. Political parties draw their power from their constituents. Constituents who see the former condition favor the former tactic (usually confusing it with a “fundamental value”), while constituents who see the latter favor the latter (engaging in the same confusion). I really object to the idea that the issue of gay marriage has some fundamental meaning or value. Or that a philosophical solution always exists to a political problem.

  23. Ryan Ashton says:

    Thank you for the reply, Dr. Carroll, but it seems to me there is further room for dispute. It’s not clear to me which claim you intend to be a priori: the claim that the principle of sufficient reason is true (which means every true proposition has an explanation), or the claim that everything that begins to exist has a cause. If the former, I agree with you that the PSR is a priori, which is to say it is assessed rationally as opposed to empirically. If the latter, though, I do not see why the claim that everything that begins to exist has a cause is a priori. If it is an inductively-derived claim, which is to say it is generalized from repeated observations of the exterior world, then it is not properly a priori; instead, it is empirical or a posteriori.

    To illustrate the point, consider two propositions: a) all bachelors are unmarried, and b) all crows are black. Both are universal claims, but only (a) is a priori, since it is true by definition. Claim (b), however, is only contingently true, and therefore must be confirmed by going into the world to find crows and see if each one is black. Again, as best as I can tell, Craig’s premise in his Kalam argument is parallel to claim (b) rather than claim (a). After observing many instances of contingent entities (or events) coming into existence, and further finding that each one was a consequence of some kind of cause, the generalization from these particulars to the conclusion that all contingent entities are caused is quite reasonably empirical. It may have turned out that we lived in a universe where contingent entities sometimes popped into being uncaused, but the only way we would know if our universe is in fact that way is to observe what our universe is like. This dependence on observation is what appears to make the first premise of the Kalam empirical rather than a priori.

    I do grant that the Kalam argument wholly depends on the truth of the PSR–that is, the first premise of the Kalam is a particular instance of the PSR. Thus, if the PSR is false, then if follows that the Kalam argument fails, and some entities in the universe can exist inexplicably. However, it seems that one must be extremely circumspect about rejecting the PSR since its rejection carries with it enormous consequences for all pursuits of explanation–including empirical science itself. For example, many empiricists are averse to theistic appeals to “God did it” precisely because it is simply too easy to invoke God every time one comes up short of other explanations. In the absence of the PSR (or at least something like it), the appeal to “brute facts” would potentially be just as hazardous as the “God did it” explanation. When you say “we need to build models and test them against data,” are you not assuming something like the PSR in order to justify this normative claim? Would it be possible, for example, to build a model of causeless effects? If each data point potentially holds the value it does reasonlessly, in what way can an empiricist “interpret” the data points to fit the data to a model?

    Should you chose to reply once again, you will have the last word. Thanks again for contributing to this interesting discussion.

  24. Sean Carroll says:

    Ryan– I could imagine taking the claim “everything that begins to exist has a cause” as either a priori or empirical. (You say “inductively-derived,” but I wouldn’t want to put it that way, since there is a crucial distinction between true mathematical induction and empirical methods.) My argument is precisely that it should be taken to be empirical. In which case, we should judge it the same way we judge every other scientific claim, using the hypothetico-deductive method. And in that case, you can’t “prove” anything starting from “everything that begins to exist has a cause”; you simply put forward cosmological models in which things have causes, and other ones in which things don’t, and try to figure out which provides a better explanation for the data. Which is what real scientists do, rather than wasting their time on logical “proofs.”

  25. FrankL says:

    Jim Cross – my apologies for getting your name wrong.

    Ok, then we have a semantic problem, I think, which is really no problem. I prefer to be rigid about science being descriptive rather than proscriptive, but, given the obvious fact that we are all conscious entities of evolution, needing to rationally cooperate or compete as the need arises, I can relax. Maybe Nature (God) does care a little.