sandeepmanocha wrote:
mikemcgarry wrote:
What the sentence is trying to say ----- (a) humans made tools 2.6 Mya, and (b) right now, we know this to be the case. There are two actions, happening at different times --- the tool making (2.6 Mya) and the knowing about the tool-making (right now).
Look at thhe grammatical structure in (A).
.... the earliest date when it is known that humans made stone tools.
What precisely is happening at that "when"-time? Is it the knowing or the making? Technically, the clause that immediately follows "when" is "it is known", so grammatically, this would suggest the knowing happened at this "when"-time, 2.6 Mya. But logically, we know that's not the case --- it's not the "knowing" that happened 2.6 Mya, but rather the tool-making. The knowing is what the paleoanthropologists are doing right now.
Hello Mike -
I am trying to understand the logical mistake for (A) being wrong.
When it says "...pushing back
by more than 150,000 years the earliest date when it is known that humans made stone tools.
Doesn't it pushes back the date of knowing. Something like,
2.6mn Yrs|..............150k yrs..................|2.45mn yrs......................................................................|............150k yrs..................(push back out earliest date of knowledge).....|Now
<--------------------------------------------------------------------------------------------------------------------------------------------------Pushed back the date of knowing, which is wrong, and hence the wrong answer. Because author's intended meaning in this sentence is about updating our knowledge about first use of stone tools which we thought to be 2.45 mn years old but are actually 2.6 mn years old?
Regards
Sandeep
Dear Sandeep,
My friend, I think you are missing the ambiguity. Think about this phrase:
the earliest date when it is known that humans made stone toolsLet's think about the particular date discussed. This could be interpreted two ways:
1) on the date discussed, humans started making stone tools, or at least leaving tangible evidence for doing so; at some much later time, we figured out from the evidence when this date ways.
2) on the date discussed, it was the first time that humans in history every had awareness that stone tools had ever been used. Now, we take for granted that, at some point in the distant past, folks used stone tools, but at some point in civilization, this was a new discovery, and the date discussed is the date of this discovery.
Of course, what the author means to say is meaning #1, but the grammar doesn't not uniquely support that meaning. On the GMAT SC, we are not allowed to give a sentence the benefit of the doubt. A good sentence says exactly what it means and means exactly what it says, and version (A) does not do this.
Does this make sense?
Mike