he's built a little toy he's built a treadmill for a snail isn't that wonderful he's a genuine scientist he's doing lots and lots of experiments with 00:11:27 animals they're very creative experiments in this case he's built a treadmill for a snail so the snail is held by a vice on a rotating ball and the snail is then um approached by 00:11:40 the investigator who chucks it under the chin like this and if you chuck the snail under the chin like this the snail will recoil not surprising i 00:11:52 would recall it as well but as you speed up the frequency of these chucks under the chin at about five hertz once you pass a frequency of about five chucks per second 00:12:05 the snail's behavior changes remarkably instead of being perturbed and trying to withdraw it tries to crawl onto onto something the qualitative nature of what's happening 00:12:18 to the snail has changed for the snail and its response or it's it's um sense making is altered and it's tried it perceives seems to perceive now a constant surface onto which it might 00:12:32 crawl now that might seem strange to you but i'll remind you that if we flash a light for you five times a second you'll see a light flashing and if we speed up the interval 00:12:44 then we shorten the interval between flashes to make them faster there comes a critical point at about 20 site flashes per second where you no longer perceive individual flashes but you 00:12:54 perceive a continuous light something like this underlies the magic that happens with moving pictures as well where you know that the action you see in the cinema is a bunch of projected still pictures 00:13:09 but they um have this character of continuous movement for you likewise in sound if we play that for you you hear a bunch of disconnected claps but if we shorten the 00:13:22 interval between the claps and speed it up there comes a point at which it changes into a continuous low pitch and that happens again about 20 hertz at about 20 cycles per second now for this snail 00:13:35 that border is at a different place it's at about five cycles per second what this shows is quite profound remember kant's synthetic a prioris 00:13:46 time for this snail is different than time for you the time that arises as a function of the body of the snail has this border at about five hertz where you have one at about 20 hertz 00:14:01 his basic insight is that worlds arise for snails that are not commensurable with worlds that arise for humans with which are not commensurable with worlds that arise for earthworms 00:14:15 the notion of an umvelt we get to determine a minute is used to describe this bodily specific arising of a world together with time and space 00:14:28 now i said it's rather weird to think of time being fundamentally different for an animal of a different constitution but i'll remind you that we can use our cinematic tricks to make ourselves aware of our own 00:14:41 limitations on the left there through high-speed photography we managed to make perceptible an event which we cannot otherwise see the event that you see there with the splash is 00:14:53 perfectly real but we can only make it manifest through high-speed photography similarly whoops there are processes going on around us 00:15:05 that we do not perceive and we can use time-lapse photography to make those to speed them up so that they become perceptible to us something like the blooming of a flower or the battles intricate battles fought 00:15:16 between brambles and hedges these make us aware that we perceive time as unfolding at a rate dictated by our own metabolism and bodily processes so this idea that time and space 00:15:32 are considered very different from count but very much tied now to the body this is quite radical