When a concept is found to be invalid, someone might say "so much for" it, which roughly means "I'm throwing this idea away." Does anyone know where the expression comes from?
Shakespeare, Richard II, 1595
KING RICHARD II: The ripest fruit first falls, and so doth he; His time is spent, our pilgrimage must be. So much for that. Now for our Irish wars: We must supplant those rough rug-headed kerns, Which live like venom where no venom else But only they have privilege to live.
and in Richard III, 1592
Sir William Stanley. I, by attorney, bless thee from thy mother Who prays continually for Richmond's good: So much for that. The silent hours steal on, And flaky darkness breaks within the east.
It may have been used that way prior, but its usage was certainly immortalized by Shakespeare and blossomed poetically and rhetorically elsewhere after these two plays.
It began use as a phrase that indicated that one was finished with something in the late 1500s. The example listed on Dictionary.com says, "So much for this year's sales figures; now let's estimate next year's." It has much more recently evolved into a dismissive, sarcastic remark. There is little information on the phrase's exact origins.