J Thomas wrote:
Pfhorrest wrote:It sounds like we agree completely. How then can you say that everything is reducible to physics, and maintain that there are questions which are not the domain of physics? Are you just dismissing those questions?
I am kind of dismissing them as an area of science.
...whether you should publish the rules for a new chess is not part of physics.
...it is not in the domain of physics to say whether people should try to maximize their income.
Yes, I agree completely. But the question I'm posing then is: if these things are not the domain of physics (and all [natural] science reduces to physics), what are they the domain of? Possible answers are "something not physics (and thus not [natural] science)", or "nothing". Which is your answer?
I guess when philosophy-of-science describes how people actually do science, it is part of physics.
Yes, and thereby not really part of philosophy, but more sociology.
It still looks to me like philosophy tells you how to choose the rules for science, and that when you choose to play by those rules you're doing philosophy. But I found a metaphor that might fit your way. When you play basketball you have to learn enough of the rules of the game that you don't embarrass yourself. But to become a basketball referee you have to learn the rules well enough that people who second-guess you about them will be wrong. And the referee at a basketball game isn't exactly playing the game. So maybe scientists don't have to understand how to do science as long as they can limp along adequately, while the people who learn in great detail how science should be done are not actually scientists but some special kind of kibitzer.
That seems like a pretty appropriate analogy, though not perfect. Referees of a sport don't have extensive debates about what the correct rules of the sport are or objectively should be, about what sports are objectively better and should or shouldn't be played in what circumstances and why; they just have some authoritative reference to what the arbitrary rules of this arbitrary game definitively are, and are tasked with knowing and applying them. They are, to mix metaphors, an executive branch, not a legislative branch. Then again that metaphor doesn't fit too well either because unlike real legislatures, philosophers don't think that whatever a majority of them decide is right magically becomes right because they decided it to be... they're more like scientists in that they're looking to find answers, not looking to make them up. Except they're more like mathematicians than scientists in that their search is conducted entirely a priori. Except...
Yeah, not a perfect analogy. But the "player:ball::referee:rules" part is nicely illustrative.
I thought you said that since it's possible to build a Turing Machine in the real world, everything a Turing Machine can do is part of physics. I have an analogy that might seem far-fetched to you. I say that if it's possible to build a physics using philosophy, then anything the physics can do is part of philosophy.
I've already agreed that the natural sciences are all sort of "applied philosophy". The only point I'm arguing is that the things physicists study do not reduce to the things philosophers study, the way chemistry relates to physics, etc.
A psychological process is something biological processes do, and a biological process is something chemical processes do, and a chemical process is something physical processes do, but a physical process is not
something philosophical processes do, any more (to adapt your sports analogy) than 'hit fly balls' is something the infield fly rule does. Hitting fly balls is a subject which batters study; the infield fly rule is a subject that umpires study; the infield fly rule applies to the fly balls which the batters hit, but an infield fly ball (the actual event of an actual ball flying through the air in a certain way) does not reduce to the infield fly rule; rather, the latter says something about
Physics is the process of telling what physical processes there are and what they do, and it -- physics, not the physical processes it studies -- is a philosophical process. Chemistry is the process of telling what chemical processes there are and what they do, and it -- chemistry, not the chemical processes it studies -- is also a philosophical process. The same one, in fact -- some kind of critical, empirical, realist epistemology that we call "the scientific method" -- applied to a different subject matter. Likewise biology, psychology, etc. Their subject matters may reduce to one another down to the subject matter of physics, but their methodologies all equally share the same core principles, which are the subject matter of philosophy, and to which the subject matters of the various sciences to not reduce, any more than an infield fly ball reduces to the infield fly rule.
Yakk wrote:Your reduction of software to hardware is in error.
(This is highly tangential, but I found it amusing and thought you might too: for some reason, I can't help but read your post in the voice of Tuvok from Star Trek: Voyager).
Hardware requires physical existence. Software doesn't. You can reduce programs to mathematical theorems, and software can "run" on abstract mathematical objects.
You seem to be driving at a philosophy of mathematics issue, e.g. "In what sense can numbers be said to 'exist'?" That's an interesting question that I have opinions on, but I think we can sidestep it for now.
In the sense that software is abstract mathematics, and abstract mathematical objects can be said to "exist", then every program that could ever be written, including ones which will never be written (if any), already exists, has always existed since before "computer" was even a term for someone who did arithmetic for a living, will always exists even if physical reality was somehow unmade, and could not have helped but exist in any possible reality. In that sense of "existence", possibility is actuality.
I don't think that's the sense anybody means when they talk about software. There are programs which haven't been written yet, which we'd say "don't exist yet". I need a program to demux an old proprietary video container on a modern operating system, but there is no such program; it does not exist. It could, someone could write it, so in the abstract mathematical sense "a program exists" like "a theorem exists" even if nobody's worked out the details yet -- but that's not the sense people use when they talk about software.
Any program which has been written and is actually executing in the real, physical world, has no more ontological import than some hardware doing something.
On top of that, you claim that physics has things that exist. I don't see how you came to that conclusion. What experiment would distinguish a mathematical construct from something that exists?
The (in)ability to run experiments to test them is what distinguishes a pure mathematical construct from an actually existing instantiation of that mathematical structure. You can't observe an Abelian group floating out there in space somewhere; but you could perhaps observe some physical phenomenon that can be modeled as an Abelian group.
It is generally supposed that if you built a simulation of reality that was sufficiently accurate, the beings inside of it would experience consciousness. And they would experience their environment and could create laws of physics, and dictate what "exists" from what does not. Yet the same simulation might store as much information about what does not exist as what does exist. The physics of the simulated consciousnesses would be the rules of what they experience -- a set of compression rules to describe their environment and predict what will happen next -- not rules about what exists or what does not exist.
You don't have to suppose this is actually happening to realize that there is nothing about physics that requires what it describes to exist. Physics is a compression algorithm on our sensory experiences that works because we seem to exist in a reality with non-maximal information content (ie, non-maximal Entropy). In fact, we seem to exist extremely far from maximal information, which implies that we can build compact compression laws that can, with high reliability, predict the state and evolution of our sensory apparatus using very little information in at least some circumstances.
Physics is applied information theory.
I agree with most of this, except this part: "there is nothing about physics that requires what it describes to exist". There very much is. We can come up with an infinite variety of mathematical models all day every day forever, but only some of them will match up with observations. Those observable things exist, and may instantiate some mathematical model; but the models are still only models of things which might exist, and have no ontological import themselves.
To put it in a more information-theoretic way: the information that constitutes the universe will compress to certain patterns and not to others. That information is what exists; the patterns it compresses to are another representation of the same information and therefore also exist. The patterns it does not compress to, on the other hand, do not.
(And on the subject of simulated realities: even if we are all in the Matrix, brains in vats, deceptions of an evil genius, dreams, or whatever, everything we're experiencing still exists and is still real; there's just more to reality than we think there is, in that case. If the apparently physics of this "reality" are radically unlike the physics of the broader reality, then we have a big topic to study: what are the physics of the broader reality, and how did they give rise to the system which we mistook for reality?)