This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...an be seen in the rare, freak cases of children who are born without the capacity to experience physical pain; such children do not survive for long; they have no means of discovering what can i njure them, no warning signals, and thus a minor cut can develop into a deadly infection, or a major illness can remain undetected until it is too late to fight it.

Consciousness �
�� for those living organisms which possess it — is the basic means of survival.

The simpler organisms, such as plants, can survive by means of their automatic physical functions...
read full book block explorer