First, with reference to your initial post, presumably all proof requires presuppositions of some sort, and these presuppositions are often philosophical.
There is such a thing as presupposing only what is either selfevident or proven by facts and self-evident presuppositions.
Secondly, geocentricism itself rests obviously on a range of philosophical assumptions derived from ancient Greek philosophy. So I don't think we can get very far with the dichotomy between proof vs. philosophical presupposition.
The functioning of any geocentric model may presuppose Greek Philosophy, the proof not so. Causality and implication are opposite directions in reasoning.
Third, you use the phrase "prove conclusively." (cf. Mr. Y’s use of "know conclusively"). One frequently finds criticisms ofscientific theories amongst creationists to the effect that such and such a scientific theory has not been proven "conclusively."
The difference between conclusive and inconclusive proof, is that inconclusive proof, or rather evidence, does not conclude against any possible doubt. If all steps are strictly logical - like leaving out no possibilities in the enumeration before eliminating, and all input is strictly true, i e either observed or self-evident, then the conclusion is conclusively true. Otherwise the conclusion is not strictly concluded, and the argument is not strictly conclusive for it.
His evidence for heliocentrism starts with three points, that are only evidence - conclusive such - against minor points of Ptolemaic geocentrism. The third also goes into argument about geocentrism:
This observation also undercuts a widely held argument against the earth orbiting the sun, namely that the moon would not beable to keep up with the earth in its revolution. Galileo showed that Jupiter's moons had no problem with this. Hence, it should not be a problem for the earth.
The major evidence (though not conclusive) for geocentrism is the direct one of the senses, which stands without such refutable and refuted Ptolemaic argument.
4) Geocentric cosmology requires the earth to be stationary. But we know now, in a way neither Copernicus nor any of the early modern scientists could have, that it rotates on its axis. ...
We see and - by sense of balance - feel earth is stationary. A stationary earth is not a problem for geocentrism, unless it be disproven. Let's dig into Michael's proof:
a) ... In addition to the 1851 Foucault pendulum experiment, there is ...
Which could be explained without abandoning the stationary earth as, forgery, magic or due to attraction of cosmos rotating around it in opposite direction, from east to west.
b) ... the repeated evidence drawn from the orbits of artificial satellites. Suppose you launch a satellite from Cape Kennedy. It goes 100 miles above the earth moving Southeast, at an angle of 30 degrees to the equator. Once the satellite is launched, the plane of its orbit stays relatively fixed. There is no significant force exerted on the satellite to alter this aspect of its orbit. Now, if the earth is not rotating, the satellite should pass over Cape Kennedy once in every orbit. But it does not. It passes over Alabama after the first orbit, Louisiana at the end of its third, and so on further west at the completion of each successive orbit. This can only happen if the earth is rotating. Hence, geocentricism cannot be true or it must modify its claim about the stationary nature of the earth, which would run contrary to both Ptolemaic and Tychonic geocentricism.
Influence by the cosmic movement westward around earth?
(5) Johannes Kepler's laws of planetary motion (later fine-tuned in Newtonian mechanics) provide a simple explanation for why the planets are in the positions they are at each day of the year on a heliocentric model. Ockam's razor or the principle of economy says that we should not multiple entities or laws beyond necessity. Kepler's "elliptical orbit" did everything and more than Ptolemy's intricate system of cycles and epicycles. It ought to be preferred solely on this basis. And the mathematics is simpler than Tychonic geocentricism. But of course Kepler's position has a distinct advantage elsewhere, namely that it explains *why* the planets move as they do. Brahe's system, even if physically possible, leaves rather inexplicable why it is that the planets have such orbits. What physical laws would explain such motions? None. This brings us to the next point.
Argument of a tired mind. The greater simplicity - or supposed such - in causality of movements is payd by greater complexion in causation of our knowledge, a k a epistemology. Kepler's laws are not of causality. Newton's mechanics is, but is the simplicity is attained by including only non-voluntary causes. And even so Newton admitted he could not explain why there is an unshaken equilibrium between gravitation and momentum, keeping planets in orbit since creation of orbital system. He supposed, if a planet came too close to flying out on a tangent or falling into the sun, God would replace it into orbit. Making that system billions of years older does not diminish the difficulty. Laplace considered it had taken the place of a system of rotating gas, which does neither explain its stability, nor is very explainable in itself, since spirals (of liquids or of gas) are usually rotating because they are set in straights and because they are drawn somewhere faster than the straights would otherwise allow.
(6) Newtonian physics implies that a smaller mass object (earth) cannot be the center of orbit for a larger mass object (sun), much less the sun plus the rest of the planets. Objects will orbit around a common center of mass. Where one object has significantly more mass than another, the center of mass lies to the center of the object with greater mass. Hence, it certainly looks as if geocentricism is inconsistent with Newtonian physics.
A) The mass of either earth or sun has never been directly measured. It has been calculated according to size by materials and massiveness, though earth seems to be crustier towards the continental plates than below, it has also been concluded the other way round, presuming Newtonian heliocentrism to be true, and seeing the orbits, what masses does that imply?
B) The implication, once again, holds true only if limited to involuntary causes, and those to the supposed equilibrium between centrifugal and centripetal forces. A football player has a greater mass than a football, yet he sometimes circles around the ball. Voluntarily. The gravitational attraction of the ball is not his motor.
C) Demonstrably, as occurs in many machines, the moving periphery can have a greater mass than the unmoving centre, if only the parts of the periphery are on opposite sides of the centre, or their action does not hurt the centre.
7 ... Stellar parallax is quite important. The 16th century astronomer Tycho Brahe objected to heliocentric cosmology on precisely this basis. He said we should expect the parallax phenomenon if heliocentricism is true, but we don't observe it. Conversely, if geocentricism is true, we should not expect this. He then noted that his detailed observations produced no evidence of stellar parallax.
If he meant that a parallax of uniform magnitude would prove heliocentrism, he was perhaps right. But parallaxes do not come in uniform magnitude. The greatest angle involved in annual parallax is 0.76 seconds of a circle. This is the angle you get with a needle's eye in the centre of the earth, and the threads piercing earth surface appr. 30 meters apart. Stars have a movement that is not parallactic as well. The greatest such is of 10 seconds of a circle - in one direction. Of course, you may reply that the parallaxes circle around and come back to same point, which is inexplainable by involuntary causes that far away from ... whatever the closer planets circle about. But that is admitting the difficulty of explaining circular or elliptic motions by non-voluntary causes.
If the parallax observed is not, as the terminology implies an optical illusion by parallax (as houses seeming to move when the train starts), which it cannot be with a stationary earth, observed parallax must be supposed proper movements of the stars, and if those are caused by voluntary agents there is no saying what distance, only what angle the parallax is. Therefore no triangulation of distance to a star showing or not parallax.
(8) A final bit of evidence in support of heliocentricism relates to the existence and orbits of extra-solar planets. Astronomers continue to build an impressive case for the existence of planets outside our own solar system but that orbit around their own star. The current number is around 63 (including the 11 most recent candidates discovered last month). The number and details of such planets is likely to increase dramatically in the next 10 to 20 years with the advancement and employment of new telescopic technology. These discoveries, pending further verification, support the idea that heliocentric systems exist elsewhere in the cosmos. Such discoveries provide additional weight to the view that our system is heliocentric.
An argument from a parallel. In Aristotle's logic that is inconclusive. Also, if these systems are closer than concluded from parallactic "measures", the bodies involved are smaller than concluded, and the parallel argument is weakened even as such.
The philosophical assumption involved in proving heliocentrism, as far as ontology is concerned, is that the movements of the heavenly bodies must be explained by non-voluntary actions and reactions, and not by voluntary actors.
Hans G. Lundahl
27 Feb/12 March 2009
Marseille
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This was forwarded to Dr. Michael Sudduth on his Facebook account.
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