Why does something being conditioned mean that it has to be impermanent? If something arose in the past, why would it mean that it can cease?

> “‘All conditioned things are impermanent’ — when one sees this with wisdom, one turns away from suffering.” -The Buddha, from [Dhammapada, verse 277](https://www.tipitaka.net/tipitaka/dhp/verseload.php?verse=277) > “Whatever has the nature of arising, all of it has the nature of ceasing.” -The Buddha, from [Kimsuka Sutta](http://www.accesstoinsight.org/tipitaka/sn/sn35/sn35.204.wlsh.html) But why does something being conditioned mean that it has to be impermanent? And why does something having arisen mean that it has the "nature" of ceasing? Most scientists believe that this localized spacetime manifold in its current state had an origin 13.8 billion years ago. The current consensus among the scientific community regarding the future of this localized spacetime manifold is that it will simply continue to expand forever if we are to believe the current cosmological data. I wrote that as an example, but likewise, I can give other examples. Its not at all clear to me as to why something having arisen means that it can cease, and its not at all clear to me as to why something being conditioned means that it is impermanent. Of course, one could retort and say that the contents of the universe might change or that in this moment, that particle will be in a different position, but that means largely nothing because there is a difference between the microscopic and macroscopic things we observe from our point of view, which is why we distinguish between something like classical mechanics and quantum mechanics. Even with this, many, e.g. Neoplatonists, would contest this notion and say that the Universal Intellect as they conceptualize it is conditioned and created as well as composite, but never changes and is eternal. All in all, its not at all clear to me what proof is given for the idea that *all* conditioned things are impermanent, and that *whatever* has the nature of arising, *all of it* has the nature of ceasing. Any help on explaining this would be appreciated.