About the word 'imperceptible'?

Question

Development is a process whereby insignificant and imperceptible quantitative changes lead to fundamental, qualitative changes.

Question 1: What's the meaning of 'imperceptible'? Does it mean that it's out of our capability to feel it, and we human being just cannot feel or know it?

Question 2: Do you agree it?

Answer 1

1. 'imperceptible', as its etymology implies, means 'that cannot be perceived' (by humans senses in this case). The changes occur in minute steps that cannot be individually recognised; but when many of them are summed together, the result is perceptible. When a child grows 0.1mm in a day, you'd have great difficulty in measuring it, let alone noticing it. After 100 days, however, the child has grown 10mm. You didn't notice it happen, but his grandmother will the next time she sees him because she only sees one 'growth step'.
2. No, I don't agree with the second part of the statement. It doesn't necessarily follow from the premise of a quantative change that we can conclude in a qualitative change. This would be like saying "he grew a lot taller and thus became more intelligent". I'm splitting hairs, of course, we all understand the intention of the statement, but by formal logic it's incorrect.

Answer 2

1. Almost, according to most dictionaries, imperceptible means:

Impossible or difficult to perceive by the mind or senses: an imperceptible drop in temperature.

And

So subtle, slight, or gradual as to be barely perceptible: an imperceptible nod.