A rule of thumb for using the phrase “let alone”: it generally follows a negative. Three examples from a online book-search for “let alone consider”
a) “NOBODY can be conscious of, let alone consider, all aspects…”
b) “But it is already an advantage with respect to interpretive economy NOT TO HAVE TO CONSIDER the possibility of having here case of type 3 of CS, let alone consider the adjectival meaning…”
c) “There is such a chaos of contentious, INCONSISTENT, UNRELATED elements in the field that it is impossible to make sense of it, let alone consider it to be scientific.”
Compare these distortions of Dr. Seuss’s “Green Eggs and Ham”:
“I would not, could not, in the rain.
Not in the dark. [LET ALONE] on a train…”
BIZARRE (after Sam tries the eggs and ham):
“And I will eat them in the rain.
And in the dark. [LET ALONE] on a train…”
Of course, you can also use “let alone” to signal a contrast or intensification of (negative) possibilities, as in these two examples:
a) “In a postmodern era of exponential change, how can we take stability seriously, LET ALONE consider it a virtue?”
b) “The embodiment of ugliness belonging to one person was too overwhelming to separate, LET ALONE consider that it was coming from a father who would do anything for his family.”
Synonyms for “let alone” include “much less” and “still less” and “gee, golly, I don’t even want to…”