Talk:Theory of impetus

Untitled
From my research, it is not likely that Jean Buridan DID reject the Aristotelian concept of the first diagram. In fact, the translation that we have linked to states: But because of the resistance of the air (and also because of the gravity of the stone) which strives to move it in the opposite direction to the motion caused by the impetus, the latter will weaken all the time. Therefore the motion of the stone will be gradually slower, and finally the impetus is so diminished or destoyed that the gravity of the stone prevails and moves the stone towards its natural place. This does not indicate that there is an intermediate period, as the article suggests. It is more likely that Buridan stuck with the Aristotelian concepts, especially since he did not appear to devote any serious time to clarifying this supposed break between himself and Aristotle. —Preceding unsigned comment added by Arathon (talk • contribs) 17:12, 12 December 2007 (UTC)

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Contradiction between this article and the 'Avicenna' article and 'Inertia' article
This article currently mistakenly claims

"In the 14th century, Jean Buridan rejected the notion of Avicenna that a motion-generating property, which he named impetus, dissipated spontaneously (a two stage theory)."

whereas the article on Avicenna contradicts this and correctly claims

"In mechanics, Ibn Sīnā developed an elaborate theory of motion, in which he made a distinction between the inclination and force of a projectile, and concluded that motion was a result of an inclination (mayl) transferred to the projectile by the thrower, and that projectile motion in a vacuum would not cease.[46] He viewed inclination as a permanent force whose effect is dissipated by external forces such as air resistance.[47] His theory of motion was thus consistent with the concept of inertia in Newton's first law of motion.[46] Ibn Sīnā also referred to mayl to as being proportional to weight times velocity, a precursor to the concept of momentum in Newton's second law of motion.[48] Ibn Sīnā's theory of mayl was further developed by Jean Buridan in his theory of impetus."

It was the Hipparchus and Philoponus evanescent or self-dissipating impetus theory that Buridan rejected, not Avicenna's theory which he adopted. To be corrected...--Logicus (talk) 15:49, 20 January 2008 (UTC)

Logicus made the following corrective edit on 21 January:

"The Theory of impetus was an auxiliary or secondary theory of Aristotelian dynamics introduced to explain projectile motion against gravity, first by Hipparchus in antiquity and subsequently by Philoponus, and was the ancestor of the concept of momentum in classical mechanics.

Trajectory according to Avicenna, rejected by Buridan[citation needed]

In the 14th century, Jean Buridan rejected the Hipparchan-Philoponan notion that the motive force, which he named impetus, dissipated spontaneously, and adopted the Avicennan impetus theory in which (i) it is only corrupted by the resistances of the medium and of gravity in the case of anti-gravitational motion, but would otherwise be permanently conserved in the absence of any resistances to motion, and in which (ii) gravity is also a downward projector and creator of downward impetus, unlike in the radically different Hipparchan-Philoponan theory in which gravity only destroys impetus but never creates it."

--Logicus (talk) 16:13, 22 January 2008 (UTC)

Impetus dynamics is not well explained here, and so I propose to add the following text after the first paragraph immediately above as a provisional improvement that can be expanded on:

'The problem for Aristotelian dynamics posed by the continuation of projectile motion against the resistance of gravity post-projection, such as a stone thrown upwards, was the question of what is the mover that keeps it moving upwards against gravity after the original projector stops pushing it, given the core principle of Aristotelian dynamics that all motion against resistance requires a conjoined mover, but there is no visibly apparent mover in such 'detached' motions. Whereas Aristotle had tentatively suggested the auxilary theory that the propellant is the medium which is endowed with an incorporeal motive force impressed within its parts by the original projector as they also excite the medium in the original action of throwing the projectile, impetus theoreticians found this theory empirically inadequate and refuted. So they replaced it with the alternative theory that the impressed motive force is impressed directly within the projectile itself by the original projector rather than in the medium, thereby dispensing with the intermediary propelling agent of the medium in Aristotle's theory as redundant. Thus impetus dynamics was a secondary theory of Aristotelian dynamics that saved its core principle from refutation by projectile motion and observed it by identifying an internal impetus as its conjoined mover rather than the external medium. What all variants of impetus dynamics had in common was the theory that an incorporeal motive force - be it called an impressed force, mayl or impetus - is impressed within the projectile by some projector.'

--Logicus (talk) 19:02, 22 January 2008 (UTC)

Projectile trajectory diagram's unsourced
Projectile trajectory diagrams of Philoponus and Albert Saxony have been flagged as unsourced, and most likely mistaken. Probably only Galileo ever represented projectile motion as zero elevation horizontal projection, as part of his celestial dynamics and cosmogony in which the planets are put into orbit by a 90 degree deflection into the horizontal by God after a period of free-fall from their point of creation beyond Saturn.

The error here may well be that what were intended as vertically upward projectile trajectories in their textual discussions implicitly referred to here may have been misinterpreted as horizontal trajectories by reading history backwards through Galilean spectacles. For whilst it is certainly the case that it can be mathematically demonstrated that the resultant of a downward uniform acceleration due to the vertical gravitational inclinatio ad contraria and a horizontal uniform deceleration to a state of rest due to the horizontal gravitational inclinatio ad quietem in some scholastic dynamics can produce the two and three stage projectile scholastic projectile trajectories for oblique projections depicted in Rupert Hall's PhD thesis - published as Ballistics in the 17th century - which are more realistic than Galileo's mistaken parabolic trajectories, nevertheless these would not produce any more than two-stage trajectories at most for horizontal projections, namely a curvilinear stage and also a second vertical stage for those special cases when the horizontal impetus is wholly destroyed by gravity before the projectile reaches the ground.

The current diagrams of Philoponus and Albert of Saxony projectile trajectories should be deleted as false and unsourced in order to avoid the misleading impression that scholastic dynamicists were silly fools and that Galileo was not grossly mistaken about projectile trajectories.--Logicus (talk) 19:59, 2 February 2008 (UTC)

tags
I added the tags based on a number of sources best summmaized here The history of science from Augustine to Galileo Alistair Cameron Crombie. Philoponus is not tied to the earlier theories Concepts akin to those deployed in Philoponus' impetus theory appear in earlier writers such as Hipparchus (2nd c. BCE) and Synesius (4th c. CE), but Philoponus nowhere intimates that he was influenced by any one of them. there is more but Ive got to go J8079s (talk) 20:26, 10 November 2009 (UTC)

Grammar
"It was introduced by Jean Buridan (14th century), which became an ancestor to the concepts of inertia, momentum and acceleration in classical mechanics."

This is not a sentence. Let's get things cleaned up. --- Dagme (talk) 17:37, 8 April 2012 (UTC)

The tunnel experiment section is horrible
The entire section is near uncomprehensible, and in places appears downright sensless. It is full of undefined, unclear, and possibly meaningless constructs. "The oscillating motion of the cannonball was dynamically assimilated..."; "the macro-cosmological paradigmatic dynamical model of the pendulum..."; etc. Worse, the section is littered with nonencyclopaedic, subjective qualifiers: "impressive literally 'lateral thinking'", "imaginative lateral gravitational thinking outside the box", etc. It also refers to nowhere-defined 'A-B impetus' and 'H-P impetus'. The whole thing smells of original research.

I am not knowledgable on the subject to change it, however. Hopefuly someone who is would be willing to improve it (rewrite it from scratch likely).

I would support a decision to remove the section entirely. It reads like spinbot content. (Trailmixers (talk) 22:04, 25 January 2017 (UTC))


 * I came here to say the same thing. The entire article suffers from long sentences that more than a minute to parse. This means that the casual reader will not read further. Probably experts in Medieval natural philosophy can understand it with little effort. I cannot.
 * I suspect the phrase "H-P impetus dynamics" is intended to mean "modifications to Aristotle's theory made by Hipparchus and Philoponus". But Hipparchus's name, which appears on this talk page, is not to be found in the article, so I cannot be sure. Does "A-B impetus dynamics" refer to something done by Buridan and someone whose name begins with A?
 * It may be that the subject matter is so abstruse that the average educated reader will never profit from it. A rewrite, however, should be made intelligible, not just to Medievalists, but also to readers who have done graduate work in physics, and are curious about obsolete physical theories. The present article is not intelligible, and serves only to reinforce the prejudice scientists have against philosophers.
 * I agree with Trailmixers whole-heartedly.   Solo Owl   00:52, 28 January 2017 (UTC)

I fully agree to throw this tunnel experiment section out, because impetus theory is a precursor to Galileo's inertial theory, while tunneling and thought experiments came up late in the 20th century.   Astroflash   13:15, 17 September 2023 (UTC) — Preceding unsigned comment added by Astroflash (talk • contribs)

Impetus and the Tunnel Experiment
Wonderful article: hugely informative and well written.

I am not writing to critique except insofar as to point out newish developments pertaining to the tunnel experiment. Possibly they are beyond the scope of the already-written piece. Possibly also, they deserve their own Wikipedia entry.

Perhaps the most important advance on the subject is the upcoming book by Martin Beech, Going Underground -- which traces the history of the idea.

https://www.worldscientific.com/worldscibooks/10.1142/11236

The hard copy publication is due out in May or June of this year. Excerpts are already available. It seems the e-book version may also be available (I haven't checked).

A point that appears to be neglected in your article and Beech's work is that the tunnel experiment need not be left without direct empirical support, i.e., as a mere THOUGHT experiment.

The standard oscillation prediction has sometimes been PRESUMED to be true, so as to form the mechanical strategy of "gravitational clock" experiments designed to measure Newton's constant G. As in the 2016 paper by M. Feldman, et al:

https://arxiv.org/abs/1605.02126

Earlier (1975) proposals to measure G with similar "tunnel-like" apparatus are found in a NASA paper by Larry Smalley:

https://archive.org/details/NASA_NTRS_Archive_19750014902

I have written to the authors of the Feldman, et al paper to urge performing a much simpler proof-of-concept experiment in a laboratory on Earth or in a near-Earth satellite. One of the co-authors, Virginia Trimble responded positively to my paper:

http://vixra.org/abs/1612.0341

I think it is important to realize that our LACK of empirical evidence to support the oscillation prediction also bears on Einstein's theory of gravity, General Relativity (GR). This is because the prediction is directly correlated with the GR prediction concerning the rates of clocks along the tunnel walls and at the center of the source mass. Specifically, the Schwarzschild Interior Solution to Einstein's equations has never been tested.

The last paper linked above provides details to understand this connection between Newton's and Einstein's theories. Most importantly, it emphasizes that certain key consequences of these theories are only PRESUMED to correspond to physical reality. In fact, they have not been tested. But THEY COULD BE TESTED, by turning the original thought experiment into a real experiment.

Cheers,

Richard Benish — Preceding unsigned comment added by 2601:1C0:CC02:D7D0:802:FC8D:F9A9:F7C5 (talk) 20:38, 24 March 2019 (UTC)  The above message was originally posted on my talk page. – Uanfala (talk) 01:09, 30 March 2019 (UTC)

Jagged_85 sock?
For the record, I think it's highly likely that Special:Contributions/217.123.87.5 is a User:Jagged_85 sock. Added several thousand characters of slightly dubious material on Avicenna... check. Lots of slightly anachronistic terms which make it sound more important than it was ('Avicenna's theory of motion')... check. Slightly shoe-horning in later thinkers ('This conception of motion is consistent with Newton's first law of motion, inertia')... check. Suspiciously high level of proficiency with referencing for an IP user... check. Determination to make it sound like a major advance from the Greeks... check. Making it sound like there was an unbroken chain of improvement via the Arabic world which created the modern theory ("This idea which dissented from the Aristotelian view was later described as "impetus" by John Buridan, who was influenced by Ibn Sina's Book of Healing).... check. Misrepresented sourcing, quoting things directly which a) are older, academic books which are incredibly hard to verify and b) were almost certainly referenced in another source which is much easier to verify... check. Managing to find a single source which vaguely supports a claim to be the oldest/ earliest/ first... check. Added the same slightly dubious material to multiple articles: History of classical mechanics, Mechanics... check. Assuming it was Jagged_85, they have at least got slightly better at providing complete references. Some of the material was quite interesting. I think I'm done cleanup for the time being, but I guess we need to be aware that Jagged_85 has unfortunately not gone away. Merlinme (talk) 13:41, 29 April 2020 (UTC)

Hipparchus and the Vaiśeṣika school
Hipparchus has sometimes been described as conceiving impetus, though not in Philoponus's terms. I'm just wondering why he isn't mentioned. Same with the Vaiśeṣika school, whose concept of vega is often interpreted as impetus, particularly in the explanations given by Sridhara and Vyomasiva. - A Morozov  &#9001;talk&#9002; 06:25, 4 May 2020 (UTC)


 * I fully agree. I therefore included Hipparchos' theory of free fall as a precursor to the impetus theory. Astroflash (talk) 13:10, 17 September 2023 (UTC)

Future Edits for the Article
Hello! I am a student and will be working on this Wikipedia article for a school project throughout the next few weeks. When looking at this article, I noticed the section "The tunnel experiment and oscillatory motion" in particular went into excruciating detail regarding the experiment, and believe this is too detailed and specialized, violating WP:NOT. (as has already been noted by User: Solo Owl and User: Trailmixers). Perhaps it deserves to be its own article. Additionally, the amount of run-on sentences makes this section a bit confusing, so I will be working to reduce this. I will be using a Sandbox for the article (https://en.wikipedia.org/wiki/User:LGUNN22/Theory_of_impetus).

LGUNN22 (talk) 17:15, 1 March 2021 (UTC)

Some Organization and Content Issues
The organizational structure of the article is confusing. For example, the article cites the theory of impetus as being a secondary theory of Aristotelian Dynamics, but never provides an explanation of Aristotelian Dynamics. Placing a section before Philoponan theory about Aristotle’s influence on the theory would provide a helpful background for theory itself.

With the introduction of Burdanist impetus, a rather lengthy quotation is placed with what one might assume to be his description of impetus (beginning “When a mover sets a body in motion…”). However, the citation indicates that the quotation provided was not written by him. A direct quotation from Buridan himself would probably make more sense. If writings from another individual must be quoted, they should be more clearly referenced (i.e. “Pedersen wrote of Buridan…” or something to that effect) to demonstrate its relevance to Buridan’s theory.The use of the phrase “in my opinion” by Pedersen is also somewhat concerning. Who is Pedersen, and why is his scientific opinion credible/worth being considered to describe Buridan’s theory?

The tunnel experiment and oscillatory motion section also has several issues. One of the initial sentences of the section describes the experiment as having “established one of the most important principles of classical mechanics,” but fails to mention what this principle is. Additionally, the placement of this sentence in the initial paragraph of the section does not make sense. “It also established one of the important principles of classical mechanics” is random considering the sentence preceding it has not been fully defended/explained yet. The same can be said for “The tunnel experiment also gave rise to the more generally…” The first point in this paragraph (“This experiment was important because it incorporated…”) should be more thoroughly explained before introducing other significant results of the experiment. The initial description of what the experiment demonstrated is unclear. “A body rises to the same height from which it has fallen” implies that this could apply to any object falling, such a ball being dropped off of a cliff bouncing back up to its initial height, which is not what the experiment actually suggests. I would recommend including the term “pendulum” somewhere in this description to indicate that the object must be in a pendulum motion. LGUNN22 (talk) 06:05, 16 March 2021 (UTC)

Thoughts for Current and Future Editors
I have completed my school project and thus have finished editing this article. However, there is still plenty of work to be done, and I have some possible suggestions to assist those who work on this article in the future: LGUNN22 (talk) 05:05, 27 March 2021 (UTC)
 * "The tunnel experiment and oscillatory motion" section still has lots of work to be done. It is still fairly wordy and unclear. Many concepts are introduced without definitions (A-B impetus dynamics, normal, H-P dynamics, etc.). Additionally, bold claims are made within the section that are never fully proven or addressed (as mentioned in my previous post on this page). Answering these questions would provide greater clarity to the reader.
 * The previously mentioned section is so detailed, it may merit being its own article. If so, the majority of the information can be placed in that article instead of its current placement in "Theory of impetus."
 * Buridan is the main individual discussed in the article. His contributions to the theory appear to be great, so this may not be a totally negative thing, but more discussion of the other scientists mentioned (Galileo, Benedetti, etc.) would be helpful. The focus on Buridan leads me to believe this article is too specialized, and that several pieces of information from within it came from an essay of some sort.