This is a quote from the book "The Virtue Of Selfishness" by Ayn Rand
...rock to reach the sunlight. But whatever the conditions, there is no alternative in a plant’s function: it acts automatically to further its life, it cannot act for its own destruction.
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The range of actions required for the survival of the higher organisms is wider: it is proportionate to the range of their consciousness. The lower of the conscious species possess only
the faculty of sensation, which is sufficient to direct their actions and provide for their needs. A sensation is produced by the automatic reaction of a sense organ to a stimulus from the outsi...