Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
seeing, seeing as, seeing as how, seeing that
The participial Seeing [that] she wasn’t ready, he sat down is Standard. Seeing as and seeing as how are conjunctions meaning “because” and are limited to the lower levels at best; some conservatives consider both locutions—especially seeing as how—countrified and unacceptable at any level.
