Introduced by Newton, the dichotomy is still central in theoretical physics. it is active in cst, quantum gravity etc.No1&3 are endorced by theorists such as Freedman& Smolin. No2 was recently proposed by the author
The 3 main branches of the dichotomy
1. The what/why.kinematics describes what exists in the world or systems i e point particles or states of systems. Dynamics is the how or behavior
2. Kinematics declares properties or parameters of motion that play central role in its repeated patterns, dynamics makes predictions about tese using distinct intra-system properties
3. The so-called dynamic concepts-based & causality dichotomy. Dynamic concepts are mass and force and are aspects of so called interactions and carry a causal inference. These imply pre and post kinematics description
The most proper distinction between kinematics and dynamics is that kinematics describes the what/why of a system, such as the states of the system or the properties of its motion, while dynamics explains how these properties change over time and interact with one another. Kinematics deals with the properties of motion that are invariant under transformations, while dynamics describes how the system behaves under different conditions.
Kinematics is concerned with the mathematical description of motion, including position, velocity, and acceleration, without reference to the forces that cause the motion. Dynamics, on the other hand, deals with the forces that cause the motion and the resulting changes in the system over time.
The distinction between kinematics and dynamics is important in physics because it allows us to understand the behavior of systems and make predictions about their future behavior. This dichotomy has been a central concept in theoretical physics since Newton introduced it, and it continues to play a crucial role in modern physics, including in the fields of quantum gravity and cosmology.
In humans' motor control, a fundamental distinction emerges in the bodily movement trajectories, according to levels of mental intent.
When the motion is deliberately aimed at a goal, there is a conservation of the path geometry that occurs independent of the motion dynamics. The body's end effectors (e.g., the hands) trace paths with similar path length and curvature, yet the temporal profiles along those geometrically conserved paths vary as a function of changes in mass, speed-acceleration, etc. This conservation can be traced in different geometric invariants and used as ways to detect anomalies in the nervous system, or track improvements (e.g., in stroke patients.) Yet, when the movement is spontaneously occurring -without a goal, this conservation falls apart and different speeds or mass changes, give rise to different curvature and pathlengths, even different torsions along the geometric path. The dynamics change the paths as they were not intended in the first place. The motor variability can distinguish when a movement is intended vs. when it spontaneously unfolds without intent. Check it out in a lifetime of work!
https://pubmed.ncbi.nlm.nih.gov/12424277/
Article Simultaneous control of hand displacements and rotations in ...
Article Space-Time Separation During Obstacle-Avoidance Learning in Monkeys
Article New symmetry of intended curved reaches
https://pubmed.ncbi.nlm.nih.gov/22038712/
Article Signatures of movement variability anticipate hand speed acc...
This is a very efficient way to blindly separate kinematics from dynamics in human and non human primate motor control.
prior work from other labs that inspired this work:
Article Kinematic features of untreated vertical arm movements
Article Do arm postures vary with the speed of reaching? J Neurophysiol
but the field of motor control confounds these two aspects of motion generation and couples space and time in their models. Empirical data from learning a new motor skill (and their neural correlates https://www.frontiersin.org/articles/10.3389/fnint.2013.00039/full ) point in a different direction from the general one assumed by the field.
Over twenty years later, I still find evidence for this separation between kinematics and dynamics of the human system, but also recognize that it is unknown or poorly explored by the field (perhaps because tensorial transformations are not something people understand well and they are the basis of the model addressing the Bernstein degrees of freedom problem that gave rise to this discovery).
Thank you Elizabeth Barbara Torres for your answer.
My question here was more narrow. On the division that exists in the physical sciences, in the way Galilleo defines kinematics by reducing all change to motion and to a mathematical description.
Good wishes for your, more broader in scope, research !
Thank you -Yes, I know, and it is a very nice question. I just wanted to highlight some applications to brain science. Physics and Math have helped in advancing Brain science considerably and applying these concepts to it have been crucial for discovering mental laws above kinematics or biomechanical invariants. Thanks for the question!
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