Bob Bridges, good to see you are back, I wish you well.
Today 'for' almost automatically means 'based on the standard of' as in:
Though small looking, she's tall for first grader
Still clumsy, he's not bad for a beginner
But in this in 1969, 'for' was definitely not like that at all:
“That's one small step for man, one giant leap for mankindâ€
Was there an evolution taking place after 1969? Or Armstrong knew it but chose to use it differently?
No, it's not a matter of evolution. Like many other prepositions, "for" has had a wide range of meanings for quite some time.
MW lists 10 definitions: http://www.merriam-webster.com/dictionary/for
Other dictionaries list even more. Both your examples are consistent with proper use.
That sounds right.
The reason I brought up the iconic statement-- see, the way it's structured, with the 2 parts contrasting dramatically, it immediately kicks off in the mind that sense of 'for' as 'by the standard of.' But as soon, you realize that cannot be ( that Armstrong cannot possibly mean to say that the achievement looks big only because mankind is puny ). So you end up with kind of a hollow feeling, as though the English is not quite tight and snug there.
I might well be the only one in the world who feel dissatisfied with that masterpiece. That's why I wonder if back in 1969 it might have sounded differently. I take it from your answer that it would have sounded same (though that 'same' is not necessarily same to you and me).
What if he had said, "one small step for A man, .."? As there is doubt about it for some people( I googled the sentence). And the version with 'a' was the one that I'd first heard, from one of my HS English teachers. The famous one seems to be the one that you quoted (as,again, I googled it). But the other is not unlikely, considering the way 'a' might be pronounced before 'man', and the possible vagueness in the transmitted voice.
[Edited]
I just looked into washingtonpost's recent discussion regarding the debate over 'a'. That's interesting.
I doubt the debate about that quote will ever end, but the "a" before "man" obviously makes more sense, and Armstrong claims he said it that way.
One thing that Washington Post article neglects to mention is how the communication system NASA was using was voice-activated, so after a slight pause it would often cut out. I've used those types of communication systems, and can say from experience they often miss short words following a pause. So in my mind, it will always be "That's one small step for a man ..."
In closing, at this time, I feel it's appropriate to say: God speed, Neil Armstrong.