OFFTOPIC: physics question

[\0xDynamite]

Sorry for this little diversion, but it has occurred to me that
physics has a bit of a logical contradiction and I think highly of the
group's rational faculties here to help me sort this out.

If light travels at a. different speed for different colors in order
to account for the rainbow of a prism, how fast is the. speed of light
then?  Is there real physics to optics?  How can light know what
direction to bend after it leaves the lens?

Am I the first to discover these discrepancies?  I know everyone tends
to bow to the priesthood on these topics, but I believe the
Establishment has failed to deliver us a secular revolution.

Cheers,

Marcos