This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...own errors; he has to discover how to validate his concepts, his conclusions, his knowledge; he has to discover the rules of thought, the laws of logic , to direct his thinking. Nature gives him no automatic guarantee of the efficacy of his mental effort.

Nothing is given to man on earth except a potential and the material on which to actualize it. The potential is a supe
rlative machine: his consciousness; but it is a machine without a spark plug, a machine of which his own will has to be the spark plug, the self-starter and the driver; he has to discover how to...
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