We can not ignore the skeptical dream scenario, that holding that the only things which really exist are ourselves and our imagined experiences. However, although there are no grounds by which we may ever determine this is not actually the case, we can provide a much more reasonable explanation by assuming the existence of objects independent to us which cause our experiences, rather than that we are generating all of them ourselves. This is obvious in that there are apparent laws and rules which govern the world as it appears to us, and so that there are appearances at all does not itself work to explain these apparent underlying laws and rules. In this way, we observe a cat move across the room toward food because it is hungry, but if it only consists of sense-data, how does a set of color patches shifting across time work to explain this underlying notion of hunger? We would have to assume that when the cat is not being provided to us as sense data, it goes out of existence and nonetheless exhibits the same condition of hunger when it returns to our senses, still moving toward its food.

This can even be extended further for humans external to ourselves, which possess seemingly such a large set of public behaviors which act as symbols that correspond with underlying private thoughts very similar to our own, that it seems impossible for us to ignore this state of affairs. And although this could still be accounted for through dreams, they are better explained by memories of waking life set in the physical world and are currently well described through the sciences. What is questionable then is that we have sometimes felt urged to correlate our senses exactly with the external objects themselves, when really they are only corresponding representations of such. Taken in this manner, we may better systemize our experiences as they relate with an external world, rather than leave an explanation of all of these apparent patterns to internal, spontaneous random chance that should seemingly not result in any observable patterns at all.

My worry is that Russell’s project of dividing up the sum of human knowledge in to a singular, united systematic web of contingency and necessity, and clean apriori and aposteriori divisions holding between everything remains highly elusive.