# What did Kant mean when he said that phoronomically motion is subjective but dynamically objective?

Reference: Kant's footnote, 4:559-560, "General Remark to Phenomenology," Metaphysical Foundations of Natural Science

In logic the either-or always signifies a disjunctive judgment, where, if the one is true, the other must be false. For example, a body is either moved or not moved, that is, at rest. For here [in logic] one speaks solely of the relation of the cognition to the object. In the doctrine of appearance, where it is a matter of the relation to the subject, so as to determine the relation to the object therefrom, the situation is different. For here the proposition that the body is either moved and the space at rest, or conversely, is not a disjunctive proposition in an objective relation, but only in a subjective one, and the two judgments contained therein are valid alternatively. In precisely the same phenomenology, where the motion is considered, not merely phoronomically, but rather dynamically, the disjunctive proposition is instead to be taken in an objective meaning; that is, I cannot assume, in place of the rotation of a body, a state of rest of the latter and the opposite motion of the space instead.

There are two distinctions: logic versus appearance and phoronomy (mathematics) versus dynamics (empirical).

• I am loving your ongoing study of Kant, which inspires me to do so as well. Commented Jan 26 at 0:42
• "Phoronomic" is what is now called "kinematic", and "subjective/objective" in this context corresponds to "relative/absolute" (to the subject or, today, frame of reference). When the motion is considered dynamically rather than merely kinematically, one is not free to assume what moves and what stays at rest, it is determined "objectively" (at the time, by Newton's absolute space). Relative to a frame, rest/motion are "valid alternatively", but in the absolute sense, it is one or the other disjunctively. Commented Jan 26 at 0:51
• I think I've somewhat untangled the distinctions. In logic, disjunction is either/or, no in between, but in the world of appearance, it CAN be black and white but it can also be both, depending on further distinctions--phoronomy, dynamics, mechanics, etc. Commented Jan 27 at 23:11
• And Philip, thank you for editing. I'm sorry I posted such a mess. Commented Jan 27 at 23:12
• @Conifold That doesn't sound right to me. There is no absolute space involved at all here. Commented Mar 21 at 12:06