• Querius
    37
    This is an attempt to get a coherent concept of the laws of nature. What are they? What are they made of? How do they work?
    Paul Davies: But what are these ultimate laws and where do they come from? Such questions are often dismissed as being pointless or even unscientific. As the cosmologist Sean Carroll has written, “There is a chain of explanations concerning things that happen in the universe, which ultimately reaches to the fundamental laws of nature and stops… at the end of the day the laws are what they are… And that’s okay. I’m happy to take the universe just as we find it."
    ...
    Physical processes, however violent or complex, are thought to have absolutely no effect on the laws. There is thus a curious asymmetry: physical processes depend on laws but the laws do not depend on physical processes. Although this statement cannot be proved, it is widely accepted.
    If Davies is correct in saying that laws do not depend on physical processes, does that necessarily imply that laws cannot be explained by physical processes? IOWs laws are irreducible to physical processes?
    Indeed, a bottom-up explanation, from the level of e.g. bosons, should be expected to give rise to innumerable different ever-changing laws. By analogy, particles give rise to innumerable different conglomerations.
    Moreover a bottom-up process from bosons to physical laws would be in need of constraints (laws?) in order to produce a limited set of universal laws.

    Finally a related question: what makes laws work?
    Joel Primack: What is it that makes the electrons continue to follow the laws?
  • andrewk
    1.6k
    When Davies says there is an asymmetry, he is thinking of the laws as being prescriptive, rather than descriptive. Prescriptive laws tell processes what they must do, as opposed to descriptive laws, which simply describe what they do.

    Hence If we think of laws as being Prescriptive, as Davies does, then the laws affect the processes but not vice versa. On the other hand if we think of the laws as being Descriptive, the processes affect the laws, but not vice versa (the patterns in the processes determine what the laws are).

    And lo, the symmetry is recovered.
  • Bitter Crank
    6.7k
    The "laws of nature" seem to be derived from observing many instances of observation from astrophysicists observing the cosmos to nuclear physicists studying sub-atomic particles, and others studying everything in between. So, the laws of nature are descriptive. Sometimes matter and energy behave in some way which effectively contradicts the law, and then the law has to be rewritten. These "legal" challenges don't occur every day, but every now and then they do.

    The same laws that I described as "descriptive" can be treated prescriptively. We know how gravity, force, and mass interact, so when we launch a rocket to Mars, the laws of nature prescribe how much thrust is needed, when, for how long, and in what direction. Think of the Cassini Mission bouncing around the complex gravitational fields of Saturn and its various moons. NASA wouldn't be able to program the on board computers or alter the programs without an exquisite understanding of precisely what the laws prescribe. When NASA scientists' understanding of the laws of nature aren't quite exquisite enough, rockets miss their targets and go sailing away into the brightly light yonder. around the sun.

    If you fall off the roof of a very tall building, be assured that your plunge toward earth is altogether in accordance with laws which will not be amended before you become a large splat! on the sidewalk.
  • Rich
    3.2k
    Before answering a question such as yours, with a high degree of precision, one must first:

    1) Enumerate the laws that one wishes to discuss and

    2) Explain how these laws are invariable through time and are applicable to every possible event.

    I have never seen this done. Proponents of such a concept as laws of nature generally prefer to discuss them in gross generalities which I reject.

    Instead, I prefer a more changeable and evolving universe as Rupert Sheldrake describes. I find this a more realistic view of the universe:

    http://www.sheldrake.org/research/most-of-the-so-called-laws-of-nature-are-more-like-habits
  • apokrisis
    4.4k
    Moreover a bottom-up process from bosons to physical laws would be in need of constraints (laws?) in order to produce a limited set of universal lawsQuerius

    Nice question. I really like Paul Davies but that column is mix of the good and bad.

    The way I would look at it is that the fundamental laws describe mathematical symmetries - which are in effect the limits on un-lawfulness. With a circle, for example, disorder can do its damnedest - spin the circle at any direction at any speed - and the circle will still look unruffledly the same. All that disordering has no real effect as the very form of the circle is indifferent to every kind of action, or attempt to break its symmetry.

    So this is a standard thing. Symmetries are emergent equilibrium states on the larger picture. They are the constraints that can't be broken because there is no possible action that could make a substantial difference. And we can apply this to a dynamical process like a Big Bang universe or other entropic systems.

    An ideal gas has particles going off in all directions, but they can't change the overall temperature or pressure of the system - its global symmetries ... (unless all the particles decide to all go in the same direction - something that can't happen in a Big Bang universe that is always cooling/expanding of course.)

    Anyway. Davies makes the useful point that most laws or constraints are "merely effective" - locked in due to symmetry breaking. It is easy to see that as the Universe has cooled/expanded, bosons have attained stable local identity and so have behaviour that is accounted for in terms of symmetries that got broken. Antimatter and matter were once in thermal equilibrium (a state of symmetry). Now all the antimatter has fizzled away leaving matter as "the law". Effectively we can chuck away the right-handed interactions of the weak force because only the left-handed ones exist to result in physical laws.

    And now my suggestion is to just roll effective law all the way back to the beginning. We don't have to work our way back to a fundamental Platonic state of being which is a perfect symmetry. Instead - if we understand laws to always be the emergent limits of disordering, the dynamical equilibrium balances that must always develop because "continued differencing makes no further difference" - then we can start the whole shebang with both disordering and ordering being the "symmetry" in play. We don't have to pick one over the other - disordering, or the quantum action, over order, or the symmetries of spacetime. Instead the two co-arise as themselves the deep asymmetry. The story is simultaneously bottom-up and top-down.

    So this is synergistic. The laws need disorder (or violent physical action - quantum fluctuations) to exist. They represent the equilibrium limits that regulate the Cosmos in being the effective symmetry states that "just don't care". Disorder loses its teeth because it can spin a circle all it likes and the circle already immanently exists as the limit of that very possibility for action. Try every form of disruption and in the end, what can't be disrupted is what is left as necessarily being the case.

    Of course that still leaves plenty of mystery in trying to track things back to the beginning. Physics can now describe a whole sequence of emergence when it comes to the development of effective laws following the Big Bang. There were a whole series of phase transitions to produce more complex states of order as the energy density dropped and the scale factor increased. However we are still trying to work out whether gravity was part of some vanilla quantum force and so there is some grounding symmetry state for reasons that will seem self-evident once we have its number.

    Yet the metaphysical problem here is that Davies (although he is big on top-down causation) is still too wedded to a Platonic conception of symmetries as "substantial things" - like something that might break like a plate if you drop it on the floor.

    If instead you go the completely effective theory route - where any foundational symmetry would itself have to be emergent along with the disordering it "ignores" (that is, the quantum action that is needed to manifest it as "a real physical thing"), then you have an elegant way past the usual "first causes" and "prime mover" quandries of metaphysics.

    The thing is we absolutely understand the nature of effective law. It is not a mysterious thing. So why not extrapolate backwards from that (as some major metaphysicians, but really no modern physicists, have done).
  • tom
    1.5k

    1) Enumerate the laws that one wishes to discuss and

    2) Explain how these laws are invariable through time and are applicable to every possible event.

    I have never seen this done. Proponents of such a concept as laws of nature generally prefer to discuss them in gross generalities which I reject.
    Rich

    The Standard Model of particle physics. You can take various restrictions of this - quantum field theory, non-relativistic quantum mechanics, in order to simplify the discussion.

    General Relativity. Restricted to Special Relativity in some circumstances.

    Neo-Darwinism.

    The laws are invariant through time because they say they are.
  • Rich
    3.2k
    I if

    1) Is this a complete list?

    2) Can you show that each law applies to every event and is invariant through all time (post and future) and are included within each other without contradiction (e.g. reciprocity of Special Relativity)?

    We are looking for laws nit evolving observations and mathematical symbolism.

    I didn't realize that mathematical equations and generalized, undefinable stuff like neo-Darwinism can say anything. I though only people can say things like what you just said.
  • tom
    1.5k
    1) Is this a complete list?

    2) Can you show that each law applies to every event and is invariant through all time (post and future) and are included within each other without contradiction (e.g. reciprocity of Special Relativity)?
    Rich

    You could leave Neo-Darwinism out, so in terms of physical reality, it is a complete list. There are only two theories. The aim is for there to be only one.

    The laws of physics apply always and everywhere. They work forwards in time and backwards in time. If the theories were contained within each other you wouldn't need two of them. Have no clue what you mean by "reciprosity of Special Relativity".
  • Rich
    3.2k
    Then I suggest that the two laws are not laws at all but rather mathematical equations that have been defined to describe a very strict set of behavior of unrelated ideas. In other words they are incomplete, non-specific, and might very well have changed, or will change over time. They are temporary though useful. Hardly reach the heights of a law.
  • Wayfarer
    6.8k
    This is an attempt to get a coherent concept of the laws of nature. What are they? What are they made of? How do they work?Querius

    I wonder how much of this enterprise is the attempt, in Stephen Hawking's words, to know 'the mind of God'. HIstorically, the notion of 'laws of nature' was grounded in the idea of the 'handiwork of God'; the laws were made by God, in a manner analoguous to how humans (or monarchs) created civic laws. Newton and even Galileo saw it in those terms. But with the decline of religion and the growth of naturalism, there has been an (often impicit) assumption that, as the divine origin of the Universe has been dispensed with, then the laws must in some sense be amenable to a naturalistic explanation. It's almost like 'reverse engineering' - the idea of dissassembling a mechanism to discover what makes it work. It seems to me that there may be insurmountable barriers to such an undertaking, however, and that the motivation might be questionable in the first place.

    'The whole modern conception of the world is founded on the illusion that the so-called 'laws of nature' are the explanations of natural phenomena' ~ Wittgenstein, TLP 6.371

    my suggestion is to just roll effective law all the way back to the beginning.apokrisis

    What if there is no beginning? Buddhists don't believe there is, and that the search for any 'beginning' is rather like the search for 'who shot the poisoned arrow', instead of seeking treatment for the poison. If it turns out that THE Big Bang is simply A Big Bang, then I would think the idea of a single beginning is forever out of reach, anyway - the universe is indeed a cyclic process of expansion and contraction, starting from beginningless time.
  • Wayfarer
    6.8k
    I suggest that the two laws are not laws at all but rather mathematical equations that have been defined to describe a very strict set of behavior of unrelated ideas. In other words they are incomplete, non-specific, and might very well have changed, or will change over time.Rich

    I think it's important to understand why mathematical laws were taken to represent 'timeless truths' in the beginning of the Western tradition. If you study the origins of arithmetic and geometry, they are of course deeply intertwined with mysticism, as in ancient cultures, the idea of 'separate magesteria' was not nearly so pronounced as it is today.

    But, the ancients who discovered such basic concepts as ratio, as geometrical laws, and so on, which is what made science possible in the first place, really believed they were seeing into a higher level of reality than what was visible to the mere senses. And, who's to say that they were not? Imagine the world in those ancient times, when there were no machines, no roads or buildings - the minds that began to understand the principles that allowed the construction of the Pyramids (for instance) would seem to be on a different level altogether.

    That is the 'romance of numbers' which is generally deprecated nowadays in favour of naturalist (i.e. neo-Darwinist) accounts, of counting being 'an adaption'. But I think it is worth remembering why it used to be seen that way, how it could be understood that what could be seen through number and ratio, was on a different ontological level to what was merely seen through the 'eyes of the senses'. That was very much foundational to science itself, and it was the revival of Platonism in the Renaissance that was one of the main ingredients of the so-called 'scientific revolution'.


    //ps//
    Entry on Nichomachus - Introduction to Arithmetic (Ἀριθμητικὴ εἰσαγωγή, Arithmetike eisagoge), the lesser work on arithmetic. As a Neo-Pythagorean, Nicomachus was often more interested in the mystical properties of numbers rather than their mathematical properties.[citation needed] According to Henrietta O. Midonick (1965), he distinguishes between the wholly conceptual immaterial number, which he regards as the 'divine number', and the numbers which measure material things, the 'scientific' number. He writes extensively on numbers, especially on the significance of prime numbers and perfect numbers and argues that arithmetic is ontologically prior to the other mathematical sciences (music, geometry, and astronomy), and is their cause.
  • apokrisis
    4.4k
    What if there is no beginning?Wayfarer

    I prefer to get beyond such claims of definiteness. You can't be radically indefinite unless you abandon a lack of beginning along with the beginning of beginning.

    the universe is indeed a cyclic process of expansion and contraction, starting from beginningless time.Wayfarer

    Yep. So like Tom and everyone else, you are stuck with a classical notion of time as a space in which there is an endless symmetry of succession. And yet we know that time and energy are in a reciprocal relation which the goal of a replacement quantum theory is to explain.

    Cycles are what you end up with if you can't get passed the symmetry of your own mathematical equations. If you can go forward, you can go back. And then from there you can repeat without making a difference.

    So sure, cyclic metaphysics seems very logical. But that's the problem. It shows you aren't ready to break out of the mental box you have constructed for yourself. A final theory is going to have to figure out what time really is. And if the theory is cyclic or reversible, then it still starts your ontology with a Platonic symmetry and not an Anaximandrian potential.
  • Wayfarer
    6.8k
    It shows you aren't ready to break out of the mental box you have constructed for yourself.apokrisis

    Pity that it has to come down to ad hominems, isn't it?

    I think it's a near-certainty that the universe will turn out to be a cyclical process of expansion and contraction, as is everything in nature. How that constitutes 'a mental box' is a bit beyond me.

    But I think it's also eminently possible that there never will be a 'final theory'. After all, if neo-darwinism is true, we're simian, all what we think we know really amounts to a cunning plan by the Selfish Gene in the service of its propogation.
  • apokrisis
    4.4k
    Pity that it has to come down to ad hominems, isn't it?Wayfarer

    You can take it personally but it was the collective "you" I was addressing.

    I think it's a near-certainty that the universe will turn out to be a cyclical process of expansion and contraction, as is everything in natureWayfarer

    Again, on what grounds - except a belief that time symmetric laws support a time symmetric reality, thus ignoring all the evidence that that time symmetry is irreversibly broken back here in reality?
  • Wayfarer
    6.8k
    Sorry for being touchy.

    With respect to the cyclical nature of reality, I think it is one among many speculative ideas being considered. After all, if there can be a single 'big bang' event, what 'law of nature' says that it can't happen more than once? Of course I know I don't have any kind of argument for that.
  • Rich
    3.2k
    As history has shown, nature is constantly changing, our knowledge of nature is constantly changing, mathematics is constantly changing, mathematical equations to describe our knowledge of nature is constantly changing, the ideas that the mathematical equations represent are constantly changing and debated.

    What equations that do exist are limited in their description and are not universal to every event. If laws exist they have yet to be articulated or enumerated which is central to the question at hand.
  • Wayfarer
    6.8k
    As history has shown, nature is constantly changing, our knowledge of nature is constantly changing, mathematics is constantly changing, mathematical equations to describe our knowledge of nature is constantly changing, the ideas that the mathematical equations represent are constantly changing and debated.Rich

    So, sooner or later, 7 will equal 6? Just a matter of time?
  • Rich
    3.2k
    7 is a symbol, not a law. It represents a multiplicity on space that has been learned in some past time, symbolically agreed upon in some past time (but actually quite decent) and this agreement has been passed down via education systems. Agreement about how to assign a symbol to a multiplicity is not a law unless you are claiming a symbolic representation of a multiplicity is a law. In which case we need not only need a complete enumeration of laws but also a definition of what a law is.

    As with God's laws, scientific knowledge and mathematical equations are subject to dispute and change in every instance.
  • apokrisis
    4.4k
    After all, if there can be a single 'big bang' event, what 'law of nature' says that it can't happen more than once?Wayfarer

    The second law of thermodynamics is the obvious one.

    Of course the second law is itself framed rather mechanically in terms of reversible Newtonian motions. And so it is quite easy to "prove" theorems about eternal recurrence ... given that time symmetry is being taken axiomatically for granted.

    Yet meanwhile back here in the real world, the Universe expands and cools eternally. We know that from observation rather than theory - the discovery of the hyperbolic curvature due to "dark energy". So we already had the problem of writing time asymmetry into theories like GR and QM by hand - we have to add a directional time signature that is not to be found in the symmetry-describing equations. And dark energy is another observable that shows we really do have a big hole in current theory.

    But anyway, at the very least, the expanding and cooling is now certain to reach a heat death, an actual Planck limit on entropification. So while it might be highly probable (with a certainty of 1) that a quantum fluctuation as hot and dense as the Planckscale would result in a big bang universe (as argued by spawning multiverse scenarios, for instance), it is matchingly (reciprocally) improbable that a heat death universe would be able to re-produce a Planckscale fluctuation of that requisite magnitude.

    Once you have struck a match and burnt it out, it is "quantumly possible" if you kept striking it that it might eventually catch fire again. Some probability can be attached to anything happening. But I think we could also say that a probablity of "almost surely zero" is zero for all practical purposes, even for metaphysics.

    We can never rule out a story of the universe as the original perpetual motion machine. On the other hand, we can empirically assert that it is screamingly unlikely to be the case. It is far more likely that we just haven't figured out the problem rather than that we can extrapolate from the success of simplifying our models of the world by presuming time symmetry - and writing in the right direction for time in ad hoc fashion to make the models actually fit the world as we experience it.
  • apokrisis
    4.4k
    As history has shown, nature is constantly changing, our knowledge of nature is constantly changing, mathematics is constantly changing, mathematical equations to describe our knowledge of nature is constantly changing, the ideas that the mathematical equations represent are constantly changing and debated.Rich

    You mean history has shown that our scientific models just keep getting remarkably more comprehensive in scope. Our ability to describe the world accurately has been improving exponentially.
  • Rich
    3.2k
    One can use what ever adjectives one wishes. The subject of this thread is laws which is a noun.

    As for accuracy, physics as moved from the Newtonian concrete to the quantum ambiguous and probable. If accuracy is defined by a probability wave then accuracy had taken a left turn. Physics is very useful but hardly precise. What is highly probable is that it will all change - again and again and again.
  • Wayfarer
    6.8k
    What is highly probable is that it will all change - again and again and again.Rich

    I remember you from another Forum, about five years back.

    Your posts haven't changed at all. ;-)
  • apokrisis
    4.4k
    If accuracy is defined by a probability wave then accuracy had taken a left turn. Physics is very useful but hardly precise.Rich

    Huh? Our measures of reality now have such precision that we can even measure the residual indeterminacy that persists despite our living in an era when the Universe is now so large and cold.

    I'll say it again. We can now quantify uncertainty to about as many decimal places as you might require.

    Perhaps you remain unimpressed. I merely then point out that you communicate with me using the resulting quantum technology and not ... telepathy or carrier pigeon.
  • darthbarracuda
    2.9k
    Natural laws are the natural extension of a Cartesian epistemologically-oriented metaphysics, one that rejects teleology in favor of mysterious, immutable forces that exist for whatever reason. One of the alternatives would be a rejection of natural laws as such, in favor of a re-instituted teleology based upon threshold dispositions and power networks.
  • Rich
    3.2k
    The question at hand is not the practicality of quantum physics. Nor is the question whether a probabilistic equation can be considered precise. The question is about laws. That is the topic I was addressing.
  • Rich
    3.2k
    I don't remember you at all. But apparently in all the years that have passed, the only law you've come up with is the number 7 which for me is as much of a law as is the letter M.
  • Wayfarer
    6.8k
    No, I wasn't saying that 7 is 'a law'. The reference was an ironic response to your statement 'mathematics is constantly changing'. There is a sense in which the scope, or the subject, of mathematics is constantly changing, but nevertheless the natural numbers are invariant, not subject to change.

    Natural laws are the natural extension of a Cartesian epistemologically-oriented metaphysics...darthbarracuda

    I'm sure that the basic idea of 'natural law' predates Descartes, although, now you mention that, how he treats it or what he says about it, might make an interesting study.
  • Pierre-Normand
    1.4k
    Natural laws are the natural extension of a Cartesian epistemologically-oriented metaphysics, one that rejects teleology in favor of mysterious, immutable forces that exist for whatever reason. One of the alternatives would be a rejection of natural laws as such, in favor of a re-instituted teleology based upon threshold dispositions and power networks.darthbarracuda

    Yes. I think there is much truth to this. According to Cartesian epistemology, the world can never be known directly through perception. There is a disconnect between the things that we (seem to) know empirically from our temporally situated perspective -- substances that have fallible powers -- and the fundamental (so called) entities posited by the exact sciences, that are subject to exceptionless laws.

    But the exceptionless laws that govern the theoretical entities posited by the exact sciences (i.e. "basic physics" and the special sciences that allegedly reduce to it) are conceived through abstracting away most or the real and relational properties of the entities that we actually encounter in the natural (and human) world and in the laboratory. The focus of physics is the (mere) material constitution of ordinary objects.

    The OP quoted Sean Carroll, a theoretical physicist, who believes that the law of physics express invariant relations quite unrelated to the ordinary time asymmetric notion of cause. The ordinary notion of causality applies to entities that have fallible causal powers -- things that act on one another or that we can make some use of. If we consider a homogeneous set of such entities, seek purely mechanistic explanations of their behaviors and abstract away from their intrinsic teological structure, and also from the practical uses that we can make of them (as real materials or artifacts) then we can achieve some explanations about the manner in which some processes are materially implemented inside of them. But we also lose sight of what those entities are and the real powers that they have. Far from being a fundamental science, physics is a very narrow science. It may appear fundamental to a Cartesian metaphysican who isn't concerned with the fact that the entities that it describes can't be disclosed in experience but rather must be abstracted away from it.
  • Querius
    37
    When Davies says there is an asymmetry, he is thinking of the laws as being prescriptive, rather than descriptive.
    andrewk
    Davies observes that “physical processes, however violent or complex, are thought to have absolutely no effect on the laws” and from this he concludes that “… the laws do not depend on physical processes.” I agree with you that this seems to imply that Davies is thinking of the laws as being prescriptive.

    The "laws of nature" seem to be derived from observing many instances of observation from astrophysicists observing the cosmos to nuclear physicists studying sub-atomic particles, and others studying everything in between. So, the laws of nature are descriptive.
    Bitter Crank

    If laws are indeed Descriptive, and processes affect the laws, then we cannot explain the existence of e.g. an immutable gravitational constant. If a certain gravitational value is produced by 2035 bosons, then another gravitational value would be produced by 1160 bosons.

    The way I would look at it is that the fundamental laws describe mathematical symmetries - which are in effect the limits on un-lawfulness. With a circle, for example, disorder can do its damnedest - spin the circle at any direction at any speed - and the circle will still look unruffledly the same. All that disordering has no real effect as the very form of the circle is indifferent to every kind of action, or attempt to break its symmetry.
    apokrisis

    I like your circle metaphor. However, how does one get from “unlawfulness” to a (perfect) circle?
    Also I don’t see how the circle metaphor elucidates the existence of various fundamental constants, which could have been very different; see the multiverse hypothesis. IOWs in many cases the existence of limits (a la the circle form) is not apparent.
  • mcdoodle
    995
    Natural laws are the natural extension of a Cartesian epistemologically-oriented metaphysics, one that rejects teleology in favor of mysterious, immutable forces that exist for whatever reason. One of the alternatives would be a rejection of natural laws as suchdarthbarracuda

    I agree with Pierre-Normand, coming at this from a more wayward angle. The metaphor of 'law' is, when you stop to think about it, quite an odd one. It was a Roman rather than a Greek concoction, to apply it to 'nature' (an odd idea too) and then 'natural law' was revived in the 17th Century, indeed by Descartes.

    Behind the metaphor, a law qua law - a legal-system law - is not immutable, nor is it something that everything obeys. The laws are what ought to be obeyed, but often aren't, or no-one on the forum would ever have smoked dope. The laws don't last necessarily beyond the next meeting of our lawmakers, praise be their devotion to public duty, although they seem eternal to anyone caught up in infringing them.

    So laws have - for determinists - an annoyingly non-deterministic linguistic cousin. Me I like them that way, but then I'm a non-deterministic sort of a fellow.
  • Querius
    37
    But with the decline of religion and the growth of naturalism, there has been an (often implicit) assumption that, as the divine origin of the Universe has been dispensed with, then the laws must in some sense be amenable to a naturalistic explanation.
    Wayfarer
    Do you hold that such a naturalistic explanation must entail a bottom-up explanation from a lower level of, let’s say, bosons? If so, do you hold that this is in principle possible?

    … the universe is indeed a cyclic process of expansion and contraction, starting from beginningless time.
    Wayfarer
    What does the fact that the universe is ever-changing — cyclic or otherwise — tell us about the nature of immutable laws? Does the fact of change contradict a purely descriptive nature of those laws?
bold
italic
underline
strike
code
quote
ulist
image
url
mention
reveal
youtube
tweet
Add a Comment

Welcome to The Philosophy Forum!

Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.