What's the difference between 'ignorant' and 'silly'?

Question

while an ignorant person will flounder and encounter difficulty

Answer 1

Ignorance is lack of knowledge.

lack of knowledge or information : he acted in ignorance of basic procedures.

Silly is behaving in a foolish manner, or showing poor judgment.

having or showing a lack of common sense or judgment; absurd and foolish : another of his silly jokes | “Don't be silly!” she said

[Both definitions from NOAD]

Answer 2

"Ignorant" is (at least on the surface) factual, while "silly" is purely an expression of opinion. For example, my manager makes decisions I consider silly (and sometimes downright stupid), while he thinks them wise (if not brilliant). But we agree they aren't ignorant decisions: he has all the necessary information before deciding, including my sage advice.

Answer 3

A possible approach to shed some light on the difference between ignorant and silly is to adopt an etymological point of view.

Whereas the origin of ignorant is pretty straightforward ("deprived of knowledge" in Latin), that of silly is more complex.

The word silly has its root in Old English and probably beyond in Proto Indo European. It comes from Old Germanic sâlîg and the associated meanings shifted gradually from...

• "happy, blissful" (OE) to
• "blessed" (c.1200) to
• "pious, innocent" (late 13c) to
• "simple-minded, lacking in reason" (late 16c)
• and today even "foolish".

So that as others have already mentioned, ignorance is a lack of knowledge and silliness a lack of common sense.