Every so often I talk to someone, and some minor thing they say or write - a misspelling, or a strangely worded chain of logic - strikes me like a knife to the heart with the knowledge that our minds are fundamentally, irrevocably different. I can't escape the conclusion that however superficially similar what we say or do may be, the processes that got us to that point must have been quite alien to one another. And I'll never know what that process is, or was, for anyone other than myself. It's like the Chinese room; you just can't tell from the outside.

It frightens me that what I think cannot be perfectly conveyed to anyone else, because the words just don't mean the same thing when the mind you put them in is different. Perhaps when I say "an apple" or "the colour yellow" the associated concept is close enough for each of us, but what about, for instance, "communism"? To me, it just means a system of philosophy, whereas to my mother - who grew up in a country under Soviet occupation - the word means something quite different. To those alive in the time of the Red Scare it must mean something else again.

And then there are so many situations where there simply are no words. When I see something like this, for instance, I want to be able to describe that sort of motion, but the existing words ("vortices", "eddies", "turbulence" and such) are just woefully inadequate.

Of course, these problems don't stop me trying to convey concepts. I simply suppress the image of each of us trapped inside our own skulls, unable to see or talk to anyone else except through the most convoluted and indirect methods, and instead just tell myself that the signals I get back from other people mean that something must get through, even if I can never confirm how close it was to what I tried to send.

Hello? Is anyone out there?