Projecting the ontology of your (flawed) internal representations onto reality is a bad idea. “Doing a Dennet” is also not dealt with, except by incredulity.
It’s a fact that the individual shades of color exist, however it is that we group them—and your ontology must contain them, if it pretends to completeness.
This is simply not the case. The fact that we can compare two stimuli more accurately than we can identify a stimuli merely means that internally we represent reality with lesser fidelity than our senses theoretically can achieve. On a reductionist view at most you’ve established “greater than” and “round to nearest” are implemented in neurons. You do not need to have colour.
Let’s unpack “blueness”. It’s a property we ascribe to objects, yet it’s trivial to “concieve of” blueness independent of an object. Neurologically, we process colour, motion, edge finding and so in in parallel; the linking of them together occurs at a higher level. Furthermore the brain fakes much of the data, giving the perception of colour vision, for example, in regions of the visual field where no ability to discriminate colour exists, and cases of blindness with continued concious perception of colour.
Brains compress input extensively; it would be crass to worry about the motion of every spot on a leopard separately—block them up as a single leopard. Asserting that the world must fit with our hallucination of reality lets you see things that are marginally visible, and get by with far worse sensory apparatus than needed. Cue optical illusions: this, this and this, for example. Individual shades don’t exist as you want them to.
It is absurdly clear that the map your brain makes does not correspond to either the territory of your direct sense perception (at the retina) or reality. On precisely what basis do you assert to project from the ontology of a bad map to the territory?
“Blue” is a referent to properties of internal representations, which is translatable across multiple instances of primate brains. You say “X is blue”, and I can check my internal representation of X to see whether I would categorise it as “blue”. This does not require “blue” to be fundamental in ontology. There isn’t a “blue thing” in physics, nor should there be. “Blue” existing means simply that there are things which this block of wetware puts in some equivalence class.
Lets move on to computation:
But if the “computational state” of a physical object is an observer-dependent attribution rather than an intrinsic property, then how can my thoughts be brain states?
Again, you seem project from an internal map of your own brain to the territory. Simply because I can look at a computer at multiple levels, say: Starting Excel, API calls, Machine instructions, microcode, functional units on the CPU, adders/multipliers/whatever on the CPU, logic gates, transistors, current flows or probability masses in the field of electrons, does not in principle invalidate any of the above views as correct views of an operating computer. The observer dependence isn’t an issue if (modulo translation/equivalence classes for abstraction between languages) they all give the same function or behaviour. You can block things up as many low level behaviours or a smaller number of high level ones; this doesn’t invalidate a computational view. What is the computation implemented by starting Excel? What details do you care about? It doesn’t matter to a functionalist, as the computations are equivalent, albeit in different languages or formalisms.
The critique of aboutness is similar to your issues over colour. You percieve “X is about Y” and thus assume it to be ontologically fundamental. Semantic content is a compressed and inaccurate rendition of low level states: Useful for communicating and processing if you don’t care about the details. Indeed the only reason we care about this kind of semantics is that our own wetware implements theory-of-mind directly. Good idea for predicting cognitive agents; not neccessarily a true statement about the world. The “Y” that “X” is “about” is another contraction—an infered property of a model.
“Time” is as flexible as your neural architecture wants it to be. Causality is a good idea, for Darwinian reasons, but people’s perception of the flow of time is adjustable. I will point out that your senses imply strongly that the world is a 2D surface. Have you ever been able to see behind an object without moving your head? I haven’t either, therefor clearly this 3D stuff is bunkum—the world is a flat plane and I directly percieve part of one side of it. Ditto time. Causality limits the state of a cognitive thing to be dependent on its previous states and its light cone at this point in space-time, and you percieve time to flow because you can remember previous brain states, and depending on them (compressed somewhat) is good for survival.
And now for unity of conciousness. It isn’t unitary. Multiple personality, dissociative disorders, blindsight, sleepwalking, alien hand, need I go on? I percieve my own representation of reality to be unitary; I know for a fact that it’s half made up. You claim that the individual issues “just can’t” be the whole story. Why? Personal incredulity isn’t an argument. The brain in the skull you call yours isn’t just running a single cognitive entity. You move before even realising “you” were going to; you are unconcious of breathing until you decide to be. Why is a unitary conciousness fundamental? Why isn’t it just a shortcut to approximate “you” and others in planning the future and figuring out the present?
tl;dr: The side of rationality during Galileo’s time would be to recognise one’s confusion and recognise that the models did not yet cash out in terms of a difference in expected experiences. That situation arguably holds until Newton’s Principia; prior to that no one has a working physics for the heavens.
The initial heliocentric models weren’t more accurate by virtue of being heliocentric; they were better by virtue of having had their parameters updated with an additional 400 years of observational data over the previous best-fit model (the Alfonsine tables from the 1250s). The geometry was similarly complicated; there was still a strong claim that only circular motions could be maintained indefinitely, and so you have to toss 60 or so circular motions in to get the full solar system on either model.
Basically everyone was already using the newer tables as calculational tools, and it had been known from ancient times that you could fix any point you wanted in an epicyclic model and get the same observational results. The dispute was about which object was in fact fixed. Kepler dates to the same time, and will talk about ellipses (and dozens of other potential curves) in place of circular motion from 1610, but he cannot predict where a planet will be efficiently. He’s also not exactly a paragon of rationality; astrology and numerology drive most of his system, and he quite literally ascribes his algebraic slips to god.
A brief but important digression into Aristotle is needed; he saw as key that was made was that the motion of the planets is unceasing but changes, whereas all terrestrial motions ceased eventually. He held that circular motions were the only kind of motion that could be sustained indefinitely, and even then, only by a certain special kind of perfect matter. The physics of this matter fundamentally differed from the physics of normal stuff in Aristotle. Roughly and crudely, if it can change then it has to have some kind of dissipative / frictional physics and so will run down.
Against that backdrop, Galileo’s key work wasn’t the Dialogue, but the Siderius Nuncius. There had been two novae observed in the 40 years prior, and this had been awkward because a whole bunch of (mostly neo-Platonists) were arguing that this showed the heavens changed, which is a problem for Aristotle. Now Galileo shows up and using a device which distorts his vision, he claims to be able to deduce:
There are Mountains on the moon (so that it is not a sphere contra Aristotle)
There are Invisible objects orbiting Jupiter
That the planets show disks
That the Sun has spots, which move across the face and separately change with time
That Venus has phases (which essentially require that it orbit the Sun)
That Saturn has lumps on it (and thus not a sphere—he’s seeing the rings) As an observational program, this is picked up with and deeply explored by loads of people (inc. Jesuits like Riccioli). But to emphasise: Galileo is using a device which distorts his vision and which can only be tested on terrestrial objects and claiming to use it to find out stuff about the heavens, which contemporary physics says is grossly different. Every natural philosopher who’s read Aristotle recognises that this kind of procedure hasn’t historically been useful.
From a viewpoint which sees a single unified material physics, these observations kill Aristotelian cosmology. You’ve got at least three centers of circular-ish motion, which means you can’t mount the planets on transparent spheres to actually move them around. You have an indication that the Sun might be rotating, and is certainly dynamic. If you kill Aristotle’s cosmology, you have to kill most of his physics, and thus a good chunk of his philosophy. That’s a problem, because since Aquinas the Catholic church had been deriving theology as a natural consequence of Aristotle in order to secure themselves against various heresies. And now some engineer with pretensions is turning up, distorting his vision and claiming to upend the cart.
What Galileo does not have is a coherent alternative package of physics and cosmology. He claims to be able to show a form of circular inertia from first principles. He claims that this yields a form of relativity in motion which makes it difficult to discern your true motion without reference to the fixed stars. He claims that physics is kinda-sorta universal, based on his experience with cannon (which Aristotelian physics would dismiss because [using modern terminology] experiments where you apply forces yourself are not reproducible and so cannot yield knowledge). This means his physics has real issues explaining dissipative effects. He doesn’t have action at a distance, so he can’t explain why the planets do their thing (whereas there are physical models of Aristotelian / Ptolemaic models).
He gets into some pro forma trouble over the book, because he doesn’t put a disclaimer on it saying that he’ll retract it if it’s found to be heretical. Which is silly and it gets his knuckles rapped over it. The book is “banned”, which means two things, for there are two lists of banned books. One is “burn before reading” and the other is more akin to being in the Restricted Section; Galileo’s work is the latter.
Then he’s an ass in the Dialogue. Even that would not have been an issue, but at the time he’s the court philosopher of the Grand Duke of Tuscany, Cosimo I de’ Medici. This guy is a secular problem for the Pope; he has an army, he’s not toeing the line, there’s a worry that he’ll annex the Papal states. So there’s a need to pin his ears back, and Galileo is a sufficiently senior member of the court that Cosimo won’t ignore his arrest nor will he go to war over it.
So the Inquisition cooks up a charge for political purposes, has him “tortured” (which is supposed to mean they /show/ him the instruments of torture, but they actually forget to), get him to recant (in particular get Cosimo to come beg for his release), and release him to “house arrest” (where he is free to come, go, see whoever, write, etc). The drama is politics, rather than anything epistemological.
As to the disputes you mention, some had been argued through by the ancient Greeks. For example, everyone knew that measurements were imprecise, and so moving the earth merely required that the stars were distant. It was also plain that if you accepted Galileo’s observations as being indicative of truth, then Aristotelian gravity was totally dead, because some stuff did not strive to fall (cometary tails were also known to be… problematic).
Now, Riccioli is writing 20 years later, in an environment where heliocentrism has become a definite thing with political and religious connotations, associated to neo-Platonism, anti-Aristotelean, anti-Papal thinking. This is troublesome because it strikes at the foundational philosophy underpinning the Church, and secular rulers in Europe are trying to strategically leverage this. Much like Aquinas, Riccioli’s bottom line is /written/ already. He has to mesh this new stack of observational data with something which looks at least somewhat like Aristotle. Descartes is contracted at about the same time to attempt to rederive Catholicism from a new mixed Aristotilean / Platonist basis.
As a corollary, he’s being quite careful to list every argument which anyone has made, and every refutation (there’s a comparatively short summary here). Most of the arguments presented have counterpoints from the other side, however strained they might seem from a modern view. It’s more akin to having 126 phenomena which need to be explained than anything else. They don’t touch on the apparently changing nature of the planets (by this point cloud bands on Jupiter could be seen) and restrict themselves mostly to the physics of motion. There’s a lot of duplication of the same fundamental point, and it’s not a quantitative discussion. There are some “in principle” experiments discussed, but a fair few had been considered by Galileo and calculated to be infeasible (eg. observing 1 inch deflections in cannon shot at 500 yards, when the accuracy is more like a yard).
Obviously Newton basically puts a stop to the whole thing, because (modulo a lack of mechanism) he can give you a calculational tool which spits out Kepler and naturally fixes the center of mass. There are still huge problems; the largest is that even point-like stars appear to have small disks from diffraction, and until you know this you end up thinking every other star has to be larger than the entire solar system. And the apparent madness of a universal law is almost impossible to understate. It’s really ahistorical to think that a very modern notion of parsimony in physics could have been applied to Galileo and his contemporaries.