https://www.coindesk.com/markets/2014/08/29/hal-finney-on-bitcoin-in-his-own-words

As Finney put it in March 2011:

“The computational power of the network is proportional to difficulty; and it appears that difficulty is proportional to bitcoin price. It follows that unless bitcoins become substantially more valuable than they are today, the Bitcoin network will never be substantially more resistant to attack than it is today. For Bitcoin to succeed and become secure, bitcoins must become vastly more expensive.”

https://bitcointalk.org/index.php?topic=4619.msg67576#msg67576

March 18, 2011