Answer:
The economic philosophy that Andrew Carnegie is referring to in this quote is capitalism.
Explanation:
It is clear from the terms used and the process described in the quote that the philosophy Andrew Carnegie is referring to is none other than capitalism. It is because Carnegie is speaking about 'competition' which according to him is beneficial in the growth.
The term 'material development' also clarifies that the quote is in the praise of capitalism. Moreover, Andrew Carnegie was himself a capitalist.