Following the argument in lecture last Thursday that radical translation is impossible and that all understanding between civilisations is necessarily indeterminate, here are links to the two philosphical justifications I used.
A good presentation of Quine's "gavagai" thought experiment is here.
The argument is in Quine's Word & Object, on Course Reserve.
Thomas Nagel's What is it Like to be a Bat? is on-line here (as well as being on Course Reserve.)