Truisms 1

Seems to me that such a truism is just renaming everything that "is" with the word "physical", which no one can really argue with. It's just a definition. The deeper question then becomes an ontological one: what is everything that "is"? Information? Theories? Consciousness? Sensations? Dreams? Spacetime? Other Universes? etc...

You forgot the qualifier, "As far as we know."

You forgot the qualifier, "As far as we know."

How would you do it with a Venn diagram? The average scientist would probably place the epistemological circle inside the ontological one. For a solipsist, they might be one in the same. However, it all really depends on what "is" means for you. Some might have the epistemological circle intersecting the ontological one - i.e. not everything that is "known" actually "exists", and vice versa. And for QM Many Worlds, ontological circles might be completely useless.

Personally, this very wells sums up a similar truism I've always held regarding the meaninglessness of the term "supernatural". What is, is natural, necessarily so.

I haven't read Wittgenstein since high school, but I knew there was a reason I liked him.

You forgot the qualifier, "As far as we know."

How would new knowledge affect this truism? I don't really understand your point.

We know what we can measure. Mostly. How can we know if there is what we cannot measure? I refuse to say if I believe that to be true or not.

I agree with Jeff. This is not so much a truism as a definition. You are defining "that which is" as "that which is part of the physical world".

What, for example, do you make of love, mercy, ennui, and the feeling of unease you get when sitting on a seat that is still warm from someone else's bottom? Do these, and other emotions, "exist"? Does truth "exist"? Can you put playfulness in the "proper domain of physics"?

Yes, Peter, that is why I said "truisms in my opinion". They are truism to me and in this case is a definition that I find true after much reflection. The reason why I think it is a truism is that whenn I was around 18 I decided to see what conceptual commitments I needed to get by were, and started with "the physical world". I have not yet needed to add a single thing. Yes, playfulness is in the domain of physics. It's in that art of the physical domain known as "terrestrial chemistry", the part that is "biology", and particularly the part that is "behavior".

I go with Susan's comment - we know only that which we can measure. Science is the process of learning how to describe the greatest amount in the fewest measurable terms. And the world is what we know, or may one day know.

Three almost spontaneous reactions to the challenge posed above:

One: What's to discuss?

Two: In my misbegotten, drug fuelled, truth-questing youth I, as a quasi Taoist/Buddhist, spent a lot of time and energy trying to discover the reality behind reality till I came to the realisation that the reality behind reality is reality.

Three: What we cannot speak about we must pass over in silence. Ludwig Wittgenstein, Tractatus Logico-Philosophicus, 7.

Footnote: For once I am not trying to be humourous or clever.

" ... What, for example, do you make of love, mercy, ennui ..."

I make them to be interpretations of the world.

"All that is the case is the physical world."

Thought experiment: Consider a blind fish philosopher in a dark, still pond that has reached thermodynamic equilibrium, in a sealed underground cave. This fish has all fish senses except sight. The fish conducts every physical experiment that is possible using its senses (but remains necessarily ignorant of colour, temperature variation, etc.) and concludes that the fish world is the entirety of existence. The fish declares that only the physical fish world exists.

Questions: Is this fish a physicalist or a solipsist?
Is it possible (assuming one of the Many Worlds models - QM, eternal inflation, string theory, etc. - obtain in the sense that they are a necessary part of a sufficient physical theory.) that we are analogues of that fish?
If we are fish analogues, are the "other worlds" physical (given that they are, even in principle, beyond our ability to detect by any conceivable physical experiment)?

we know only that which we can measure.

I cannot directly observe someone else's consciousness, qualia, or internal knowledge - does that mean they don't exist? What a strange way for reality, all knowledge, and being to be structured - around one consciousness and one alone. And even what you think you do "know" can never be given any absolute ontological reality (phenomenal vs noumenal). For example, many people still walk around with a billiard-ball conception of the universe, which was proven inaccurate long ago.

And what determines what you will measure in your next scientific or life adventure? To a large extent, intentionality or free will - you will know what you want to know - what you want to discover, read, and learn. Your will. Seek and ye shall find. And what you do not know, you cannot and will not speak about, and must necessarily pass over in silence, as per Thony and Wittgenstein.

I know most folks have so far focused on the Truism, but I am having a hard time understanding the Corollary. What could it possibly mean to find something that is not physical? By what method would one find it? If what is meant is just that if you observe a phenomenon that appears to be at a different "level" than atoms and molecules, then that phenomenon can be specified in purely physical terms, then it's just reductionism. Nothing wrong with that, necessarily, but it isn't particularly interesting about reductionism(although I guess since it is meant to be a corollary of a truism, maybe it's designed not to be interesting). Though this would answer some of the objections raised in other comments about love, playfulness, etc. If it is meant to imply that it is possible to discover something that is not physical, it would seem to contradict the truism.

"whenn I was around 18 I decided to see what conceptual commitments I needed to get by were"

Jesus H Christ! At 18 I didn't know what "conceptual" or "commitments" meant. I knew that the only thing I needed to get by was to leave my family home, my intolerant father, and the xian BS. Which I did without hesitation.

That was decades ago, and unfortunately I have never had a good relationship with my parents since.

Yes, playfulness is in the domain of physics. It's in that art of the physical domain known as "terrestrial chemistry", the part that is "biology", and particularly the part that is "behavior".

Sorry to dig up an old bone of contention, but some might say that observable behavior is not equivalent to the corresponding first person experience. The two may be ontologically different - and not simply an apparent difference due to different vantage points of observation. That includes playfulness, love, ennui, and all qualia.

For example, if you are having a dream, is that first-person dream experience identical to the sum total of all physical behavior that an external observer might record (neurons firing, neurochemistry changes, etc)? The experience may appear to supervene on, and be correlated with the physical, but is it ontologically identical? That is the million-dollar question.

Qualia? Never actually encountered one. All I know is that observer systems have perspectives and machinery. All the rest is just physics...

You've never experienced anything subjective? If an observation doesn't fit into a model you like, do you ignore the observation?

Oh yes, lots of subjective stuff. Never a quale to be spotted, though. Just me in my head experiencing the world in physical ways.

As to the second question, I don't know why you ask that. Of course I change models to suit observations and not the other way around (but that's another Truism - I now have six lined up).

Hmmm, I always thought quale = subjective experience. In fact quale = experience, since all experiences are subjective (at least, I cannot conceive of an objective experience). So if you are experiencing the world in any way whatsoever, that sounds like qualia to me. I'm glad you're not a zombie! (I'm just curious though, how is having an orgasm "experiencing the world in physical ways"?)

If subjective experiences are just physical dynamics, then anything physical should be experiencing something, and you should be able to write a program or build a simple machine that has experiences, and find some way to prove it. Since physical things interact, so should experiences. Should be simple, right? Hmmm, but there is this little problem of subjective experiences being stubbornly "subjective". Otherwise, reality would be experienced as the entire universe, and for some odd reason that's not happening. I wonder what the physical reason for that is?

A quale is the "what it is to be like" having some experience over and above the mere experience itself. I deny that we need these mysterious, indefinable and ultimately useless objects in our ontology. As you state it, these things are merely defined into existence, and so are a lot like the ontological proof of god.

As to what it is to experience something, I suspect the term "experience" is meaningless, and hence the folk ontology it relies on is false. Things affect other things causally. Some of these things affected are systems that are capable of knowing things in sufficiently recursive ways ("I know X, and I know that I know X") that we say they "experience" them, or are "conscious", but it's all just physics.

This is a fruitful Truism, isn't it?

Experience is meaningless? Not to me, it isn't. See, that's what I mean by ignoring observations to try to shoehorn reality into a preconceived model. That's what consciousness deniers do, because it simplifies everything for them. In my opinion, they bury heads in the sand. As Einstein said, make things as simple as possible, but no simpler.

That's not what I wrote, Jeff. I said the term is meaningless. Whatever the term was applied to exists as much as it ever did. I still do whatever things it was that were denoted by that term, but the term has no simple denotation, no intension, no natural reality. It's like a term "frue", which applies to flies in the daytime, and pebbles no bigger than 15mm after sunset.

Four: WYSIWYG

Things affect other things causally. Some of these things affected are systems that are capable of knowing things in sufficiently recursive ways ("I know X, and I know that I know X") that we say they "experience" them, or are "conscious", but it's all just physics.

No, see.. this is example of what I just said: fitting the phenomena to the model rather than the other way around.

There is a fundamental difference between objective and subjective. All of the properties of a normal physical system are open and inspectable to multiple independent observers. But subjective experience is closed to everyone except the subject. Outside observers can make guesses about the subjective state of the subject based on its correlated objective physical states, but they can never really know it or observe it like the subject does. It is cut off from them like a black hole. How can those hidden subjective states exist in an open physical universe? They are qualitatively different things. The only way you can get around it is to just flat-out deny that consciousness and experience exist at all. To me, that is ignoring an observation, and is traveling down the road to insanity.

It's like a term "frue", which applies to flies in the daytime, and pebbles no bigger than 15mm after sunset.

Well, it means something to me and others. Experience is everything that I am continuously aware of. It is the continuous state of the universe relative to me, and therefore necessarily subjective. You said that you have subjective experiences as well, so it must mean something to you.

What, for example, do you make of love, mercy, ennui, and the feeling of unease you get when sitting on a seat that is still warm from someone else's bottom?

These are all the result of electro-chemistry - the physics of the brain. Emotions are physical in the same way acidity is physical.

The only difference between a subjective observation and an objective observation is that the mechanisms of objective observations are known. If the brain making a given subjective observation were sufficiently well understood, said observation would be rendered an objective observation through rigorous analysis of said brain.
If neuroscience stays on the path it is on now, scientists will gradually learn more and more about how subjective observations are made - and thus how to translate them into objective observations.

If the brain making a given subjective observation were sufficiently well understood, said observation would be rendered an objective observation through rigorous analysis of said brain.

I have to disagree. No matter how much you know about a physical system correlated with a subjective experience, you will never actually be the subject and experience it from that perspective. It is a different order of knowledge.

Jeff, #3

What I see is that you don't understand, and you have no desire to understand. It is not in you to comprehend, to desire comprehension, to gain comprehension. You need relativism, for with out relativism you would need to confess to your ignorance.

Can we know completely? No. Can we know perfectly? No. For we are imperfect beings living in an imperfect universe. We have limitations and we cannot change that.

But you'd rather insist on perfection. Perfect knowing, perfect understanding. Perfection we can never achieve, for living as limited creatures in a limited realm we will always be made imperfect by our limitations.

And you complain and kvetch because this all means that wonderful you will be imperfect now and into the foreseeable future. You can't stand that, for you need the admiration that comes from being seen as perfect. To acknowledge your limits means having to live with those limits, and you're not mature enough to do that.

"As far as we know." means just what it says. As far as we know, because we don't know everything, because we can't know everything. There will always be more to learn, new things to learn. Our knowledge will expand and our old knowledge will pass away. And all your money won't another minute buy. You shall pass. Your knowledge will pass with you. New knowledge will replace what you knew, supplant what you knew. You will be no different that anyone before you, or anyone after you.

Enjoy what you can of your game, for it is a useless game that teaches nothing, amuses no one. Enjoy the chains you burden yourself with, as they retard your progress while your contemporaries make progress.

For you are but an ape, and a cowardly ape into the bargain.

Alan, #26 ??? I concede. I'm having a hard time comprehending your post.

On a second reading... Relax Alan, have a beer. This is just a blog (not to detract from it's coolness or anything). But I think you may have an excellent point. Philosophy can be a heavy thing. Maybe the evolutionary explanation for it has something to do with an overdeveloped survival instinct - trying to understand too much around you. I'm just some guy spending way too much time trying to figure out what he's involved in. That's what happens when you forget to buy beer (Fosters Bitter for me). We should get more into Epicurus, I think.

Jeff, some things are just beyond the pale. One ought never on this blog mention a preference for Foster's Bitter (*ptui*!). It's Cooper's Pale Ale (which is the pale that FB (*ptui*!) is beyond).

I know FB isn't a real aussie beer, buy I can't get Cooper's Pale Ale. And have you ever tried Coors or Bud? Nasty. Some places actually pay you to drink that swill. The beer situation over here is desperate. It's like alright, bag of otter's noses then, and I'm forced to take FB. Except when there's some decent german beers around.

Re. Tim E (No. 10)

We are like your blind philosopher fish in a much more mundane way. Consider the radio I'm listening to right now: it uses a phenomenon (radio waves) that until the discovery of radio transmitters/receivers, was impossible to us to perceive at all. And yet, we have no doubt it is part of the physical universe.

The fish would be insufferably arrogant to claim that it knew everything about the whole world. But the fish philosopher would not be overreaching to claim that, were it to discover something radically new, like light, or places above ground, or anything beyond its cave, that those new things would be just as physically real as the things it knows from the cave.

Suppose we discovered tomorrow that Harry Potter was non-fiction, that there really were people who, with the right words and gestures and force of will could do things that defy our current understanding of the universe. There are two possibilities regarding our understanding of magic: either we can characterize it in a repeatable, communicable way, or we can make no testable assertions about it at all.

If we can characterize it, then it is just a new, strange form of physics (and surely Hogwarts is not as weird as quantum mechanics). If not, then our "knowledge" of magic sounds more like confusion: neither demonstrable, nor reproducible, nor teachable.

Re. MPL (#31)

The problem here is: What do mean by "physical universe", and "physical reality"?

I assume that by physical universe you mean, like many physicist (but not all; consider the Copenhagen interpretation of quantum mechanics which posits that the wave function "collapses" only when an observation is made and thus the observer "creates" his reality by observing), what Tegmark calls the "external reality hypothesis": that is that there exists an external physical reality completely independent of an observer. Tegmark argues that the External Reality Hypothesis implies that, given a sufficiently broad definition of mathematical structure, our external physical reality is a mathematical structure.

When you assert that "There are two possibilities regarding our understanding of magic (physics analogue): either we can characterize it in a repeatable, communicable way, or we can make no testable assertions about it at all." you are, I assume, asserting that this phenomenon, magic, can be measured in some sense and from these measurements we can eventually arrive at a theory that will allow us to make predictions of its behaviour, etc. In short we can express this magic as a mathematical structure. Indeed, many theoretical physics seek to find a complete and inclusive mathematical description of the universe sometimes referred to as a "Theory of Everything", or "TOE", and it can be argued that all of physics is simply an attempt to measure all phenomena and describe these phenomena mathematically.

Herein lays the problem: if physical reality is isomorphic to a mathematical structure - there exists a one to one correspondence between the mathematical structure and all physical phenomena - then it can be argued that they are one and the same thing. But, if "physical reality is a mathematical structure then we must answer the question: Is mathematics discovered, or is it a creation of the mathematician(s). If discovered, precisely where were they looking? If created, then why can they not create a mathematics where 1+1 = 5?

So, how do we define physical reality? Does it exist beyond the mind of the observer (mathematician), i.e. is there an external reality?

I would maintain that the statement "...All that is the case is the physical world" is a hypothesis rather than a truism.

Re No.32

I'm not insistent on creating a mathematical model of magic as proof of knowing about it. Something that is cogently explainable and repeatable (e.g. "When a wizard makes this gesture, that happens") is sufficient.

More seriously, I think the characterization of an isomorphism as showing that two things are "one and the same thing" is a misrepresentation. An isomorphism is a demonstration that two different things share one kind of structure. For instance, the logarithm is an isomorphism between the real numbers under multiplication and the real numbers under addition. That is, log(a*b) = log(a)+log(b). However, I think it would be silly to call addition and multiplication "one and the same thing".

The mathematical structures that model scientific theories are isomorphic to the things they describe because they were constructed that way. I don't think it's any more mysterious than the fact that the planetarium is isomorphic to the sky outside---it was built that way on purpose.

Lastly, it's not necessary for the purpose of this argument to define physical reality, or whether it is external to the observer or not. All that is needed is to show that whatever physical reality is, everything new we discover is also physical. Demonstrating that discovery of something new has the same character as the discovery of things old is sufficient, I think, to demonstrate that.

The mathematical structures that model scientific theories are isomorphic to the things they describe because they were constructed that way. I don't think it's any more mysterious than the fact that the planetarium is isomorphic to the sky outside---it was built that way on purpose.

Well said, sir!

Well said, sir!

Hear!Hear!

If created, then why can they not create a mathematics where 1+1 = 5?

As stated your question borders on nonsense, firstly you are not talking about 'a' mathematics (a meaningless concept as there is only one mathematics, the sum total of all of the mathematical disciplines) you are only talking about an arithmetic. As you have written it, substituting arithmetic for mathematics, the answer is simply; you can't by definition! The number, operation and relation symbols in your arithmetical statement are so defined that this statement is per definition false. If your question is, why can't we create alternative non-isomorphic arithmetics the answer is we can and have done so many times, take for example matrix algebra. Moving to another group of mathematical disciplines geometry, it is well known that a central question in astro-physics is, is space Euclidian or Non-Euclidian and if the latter hyperbolic or elliptic? Or then again maybe it's Riemannian! We create different arithmetics, algebras, topologies and geometries to describe different aspects of reality and often as our knowledge of reality changes and evolves then we change the mathematical language that we use to describe it.

First: John, thanks for this. It has provided me with encouragement to more deeply consider many of the speculations by theoretical physicists that (not being a theoretical physicist) I would have otherwise simply glossed over as interesting but not relevant to an observationalist (and sometimes experimentalist) like me.

Thorny C: "If created, then why can they not create a mathematics where 1+1 = 5?" Sorry, the "a" was a slip of my pinkie, it seems to insert itself accidentally - perhaps due to my typing style. The point I was trying to make is that all mathematics seems to be as valid as universally (and perhaps more universally valid than) physical theories.

MPL: All mathematical structures are just special cases of one and the same thing: so-called formal systems. A formal system consists of abstract symbols and rules for manipulating them specifying how new strings of symbols (theorems) can be derived from given ones (axioms). Supposedly the wizards magic incantations are the symbols and his gestures are the rules for manipulating them, or something like that.

To be fair to Tegmark, he claims that mathematical structures "are "out there" in the sense that mathematicians discover them rather than create them, and that contemplative alien civilizations would find the same structures". If I understand you correctly when you assert that "The mathematical structures that model scientific theories are isomorphic to the things they describe because they were constructed that way" you would disagree with Tegmark and claim that mathematics is created, not discovered.

The planetarium is not isomorphic to the sky outside because the planetarium projector displays a one to one correspondence to only some of the objects and phenomena that are present in the sky; it is limited both by magnitude (astronomical) and by the astronomical knowledge available to the maker of the projector. there are many (perhaps infinitely many) astronomical objects that no projector displays.

To many theoretical physicists the mathematical equations that would comprise a "theory of everything" describe not merely some limited aspects of the physical world, but all aspects of it. It means that there exists some mathematical structure that is isomorphic to our physical world, with each and every physical entity in the universe(s) having a unique counterpart in the mathematical structure and viceversa. Tegmark claims that there would be, therefore, no way of distinguishing the mathematical structure from the physical world.

There are two tenable but diametrically opposed paradigms (I would claim they are hypothesis but will use Tegmarks language) regarding physical reality and the status of mathematics, a dichotomy that arguably goes as far back as Plato and Aristotle, and the question is which one is correct. I would characterize these as the
ARISTOTELIAN PARADIGM: The subjectively perceived perspective is physically real, and the mathematical formalism is merely a useful approximation. (Physicalism?)
or the
PLATONIC PARADIGM: The mathematical structure is physically real, and the subjectively perceived perspective and the language we use to describe it is merely a useful approximation for describing our subjective perceptions.
I suggest that neither can be called a "truism" but either can be accepted as a working hypothesis.

When MPL you observe that:

"Lastly, it's not necessary for the purpose of this argument to define physical reality, or whether it is external to the observer or not. All that is needed is to show that whatever physical reality is, everything new we discover is also physical. Demonstrating that discovery of something new has the same character as the discovery of things old is sufficient, I think, to demonstrate that."

I concede.

Even for an Aussie, it's a bit cheeky to follow "The world is all that is the case" with "All that is the case is the physical world". As I recall, Saint Ludwig said "The world is the totality of facts, not of things," so perhaps out of respect one ought to say "All that is the case is the totality of physical facts."
Pedantically yours....
Happy New Year (bleatedly)

Demonstrating that discovery of something new has the same character as the discovery of things old is sufficient, I think, to demonstrate that.

Interesting. But I think that may model the mental more than physical. One of the properties of knowledge is that it is always incomplete. Past knowledge serves as a filter or a lens through which future knowledge is created and perceived. Neural nets model that by assigning weights. However, the neural net model is also knowledge. For what we call knowledge, it is not only objects that exist, but objects and subjects. The fundamental problem is that none of us actually lives in a physical world. We live in a mental world, whether we like it or not.