This is how we must answer them: However much the mineral may progress, it cannot comprehend the vegetable world. Now, that lack of comprehension does not prove the non-existence of the plant!
To however great a degree the plant may have evolved, it is unable to understand the animal world; this ignorance is no proof that the animal does not exist!
The animal, be he never so highly developed, cannot imagine the intelligence of man, neither can he realize the nature of his soul. But, again, this does not prove that man is without intellect, or without soul. It only demonstrates this, that one form of existence is incapable of comprehending a form superior to itself.
This flower may be unconscious of such a being as man, but the fact of its ignorance does not prevent the existence of humanity.
In the same way, if materialists do not believe in the existence of the soul, their unbelief does not prove that there is no such realm as the world of spirit. The very existence of man’s intelligence proves his immortality; moreover, darkness proves the presence of light, for without light there would be no shadow. Poverty proves the existence of riches, for, without riches, how could we measure poverty? Ignorance proves that knowledge exists, for without knowledge how could there be ignorance?
Therefore the idea of mortality presupposes the existence of immortality—for if there were no Life Eternal, there would be no way of measuring the life of this world!
If the spirit were not immortal, how could the Manifestations of God endure such terrible trials?
Why did Christ Jesus suffer the fearful death on the cross?
Why did Muḥammad bear persecutions?
Why did the Báb make the supreme sacrifice and why did Bahá’u’lláh pass the years of his life in prison?