Saving is investment, as long as you mean it in terms of a bank account & fractional reserve banking, in which case banks just re-lend that money to someone else as for example a loan or mortgage.
The only reason saving it in a bank account is an investment is because more people are borrowing than saving, thus the bank makes money and gives you a share of the profits (that's your saving's interest). If everybody's saving, nobody gets any return on it and all that money does absolutely nothing for society at all.
