[coldtea]

>So why do we talk so imprecisely about objects as if they have permanence? Why is it the same river the next time we step in it?

Because the concept of river describes a body of water in flow starting from and passing through specific geographical locations.

Those all remain, even if the water at any point X of the river changes...

[goatlover]

Those all undergo change as well. In context of the parent, any change whatsoever results in a new object. Which was the point of Heraclitus not being able to step in the same river twice. It's all flux.

That's what motivated Plato and Kant to come up with their philosophical responses to the flux. One with eternal forms and the other with categories of thought.

[coldtea]

>Those all undergo change as well

And we are free to disregard small changes, like we do everywhere.

I'm aware of Heraclitus' thought (and other pre-socratics, Aristotle, Plato, Kant, Hegel, and many others besides) but it's not a binding observation (that one should fell compelled to respond by resolving some great paradox).

"Yeah, the river undergoes small changes all the time, and bigger changes from time to time. Still enough remains common for us that we still don't care and will call it by the same name, what are you gonna do about it?" is a nice common sense response...

[goatlover]

Right, but the paradox is that a bunch of inconsequential changes lead to major changes over time, such as the ship being replaced plank by plank until it has none of the original material.