On Laplace's (the mathematician) wiki-entry http://en.wikipedia.org/wiki/Pierre-Simon_Laplace the following is stated:

"The concept of a potential occurs in fluid dynamics, electromagnetism and other areas. Rouse Ball speculated that it might be seen as "the outward sign" of one of the a priori forms in Kant's theory of perception.[8]"

Now, simply stated, what's up with the last sentence? Can anyone inform me on this relevance between a potential and kant's theory of perception?


2 Answers 2


I haven't read your link, but I will explain the two terms in Kant. Regrettably, they are not easy to understand or follow, because they are tightly integrated into Kant's philosophy of mind, which is probably unfamiliar territory and understands the mind in a very different way than your average man on the street.

I would suggest you start here with the SEP entry on Kant and space-time. Basic idea is this: For Kant, space and time are things we bring to our perceiving of the world rather than things we get from the world. There are two interpretations of what he's saying. Kant's detractors and postmodernists primarily maintain the metaphysical reading whereby Kant would be saying that time and space don't exist in the real world. They only exist as mind brings them. Kant's defenders almost all disagree and maintain the epistemological reading whereby what Kant is saying is that for us as human perceivers, we bring time and spaces as forms of sensibility. In strong support of the latter is Kant's refutation of idealism in Critique of Pure Reason.

Building on top of this, Kant thinks that to move from perception to objects we add to the forms of sensibility categories of the understanding. Kant believes there are exactly twelve such categories, conveniently grouped (or contrived) into four groups of three each.

You can read more also on the SEP entry on categories. For our purposes what matters is the grouping called "modality." For Kant, the possible, the existent, and the necessary form a set. And when we have knowledge of an object, we place it under one of these categories. The possible and the potential are synonymous, so when we experience an object under the category of the potential, we believe the object to have capacities not presently realized in time which we would sense as it is realized.

  • Isn't Kant saying that space & time don't exist in the noumenal aspect of the world; but they do exist in the phenomenal aspect; which thus makes it objective? This appears to be what Schopenhauer is saying in his critique of Kant; in your typology of Kants defenders, he appears to be metaphysical rather than epistemalogical. Sep 13, 2014 at 5:18
  • Regarding Schopenhauer, he is not a defender per se. He's building his own system which hinges on interpretations we would not consider credible now. The critics and defenders language refers to post-WW2 interpretation.
    – virmaior
    Sep 13, 2014 at 5:20
  • Regarding the first part, that's what the metaphysical interpretation says. But the question is whether Kant is a skeptic regarding knowledge claims about things-in-themselves (which metaphysical interpretations generally equate to the noumenal) which would make his claim epistemological (i.e., I have no idea what the world is like for non-bats, but I know bats bring space-time as interpretive frame) or actively declaring such things are completely constructs of the mind (as postmodernists and metaphysical interpreters prefer for somewhat opposite reasons).
    – virmaior
    Sep 13, 2014 at 5:22
  • I've supposed that Kant regards space and time as 'synthetic a priori' - so things that are of the mind ie a priori and of the world ie synthetic (which suggests synthesis). Its not that space is entirely a mind thing, nor a phenomenal thing; but synthesised as a reality; I suppose one could question why a priori tautologies are in the mind; and I suppose that is answered that they do not obtain in the world. Sep 13, 2014 at 5:29
  • Clearly objects and sensibles build on things out there for Kant as syntheses, but that doesn't at all address what I refer to. Merely, because our perception and understanding are based on what is real doesn't say anything about the real by itself. Regarding the antionomies, they are in the mind because they reflect contradictions for the way understanding works. But a second problem is that "world" for Kant is an idea we in our conceptual framework... Again, all of this ties to whether we see Kant as an epistemologist or someone doing metaphysics. Strong arguments exist for the ep. interp.
    – virmaior
    Sep 13, 2014 at 6:12

Rouse Ball is indulging in analogical thinking:

First potential, which is literally not sensible, ie I can't sense it; for example I cannot see or feel gravitational potential.

This becomes real when it becomes kinetic which is sensible: I can feel the force of a stone thrown at me, or I can see it moving. Thus potential activates itself in the world by moving a stone.

This represents the scientific analogy or correspondance to Kants a priori forms of cognition (which include time, space, number); they themselves aren't sensible to us - I cannot see time, or space or number; they become real when synthesised with sensory intuition: I see things move, ie the hand of a clock or a car move; thus inferring time; I walk in space or kick a ball in about; thus experiencing space; I pick up one or two bottles.

This sensory input; or intuition in Kants phrasing is essential to grounding the mind; thus this is why sensory deprivation is either disorientating (in controlled experiments) or induces states of mind not dis-similar to psychosis (in long-term solitary confinement say in prisons).

  • The middle paragraph is not exactly right for Kant.. but it might be good enough for the analogy. For the sake of correctness, what Kant is saying is that time and space are seen as the forms are applied to objects and sensibles, but there's no "seeing" of the forms. They can however be known through the use of reason which stands higher than understanding.
    – virmaior
    Sep 13, 2014 at 5:24
  • Sure - thats why I said you can't 'see' time or space itself;but there an intellectual understanding of the forms that relates for example space to geometry; and there is a sensible understanding of space that relates to its phenomenal structure; its experiential quality; or qualia. Sep 13, 2014 at 5:35

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