Normal full-term babies are all born with certain instinctive reflexes that disappear by the age of two months. Becau...

Joeyspause March 31, 2014

Sufficient text indicator

If the first sentence has "all", which introduces a sufficient condition, why isn't "instinctive reflexes" the sufficient condition? I don't understand why normal full term babies is not the necessary condition here based on the terminology

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Naz April 9, 2014

You're right in recognizing that the word "all" introduces a sufficient condition. However, we are dealing with words, as opposed to math, so the "formulas" you use require an understanding of what the sentence is actually saying.

The first sentence says: "Normal full-term babies are all born with certain instinctive reflexes that disappear by the age of two months."

What is our subject? Normal full-term babies.

Since our focus is on normal full-term babies, the statement is saying all normal full-term babies are born with certain instinctive reflexes that disappear by the age of two months. It is not saying all things born with certain instinctive reflexes that disappear by the age of two months are normal full-term babies.

Being a normal full-term baby is sufficient to prove that it will have certain instinctive reflexes that disappear by the age of two months. Meaning, "normal full-term baby" is the sufficient condition, and "instinctive reflexes" is the necessary condition. So, though it is true that "all" introduces the sufficient condition, you still need to know what the sentence is saying to determine what the "all" is actually qualifying. In this case the "all" is qualifying "normal full-term babies."

Hope that helps! Let us know if you have any other questions.