The point regarding increasing consumption would be that you don't 
have to FORCE savings to make investment happen.  Nor do you have 
to take a moralistic stance that saving is somehow more "pure" and 
better for us all than consumption. 
     The point is that when people consume, they are spending on 
goods and services.  Right?  Well, that is incentive to SUPPLY 
goods and services.  Right?  If the society has unusued productive 
capabilities (and the big question here is why would it?) and/or 
if there is great unmet productive POTENTIAL (say, people with 
productive potential who are not getting educated when they could 
be?  Or prejudice that keeps qualified people out of jobs?) -- 
then making it possible for people to consume more is going to 
lead to an increase in real demand for real goods and services, 
and therefore it will be PROFITABLE to supply those goods and 
services and therefore it will be ECONOMICALLY SOUND to INVEST 
in theprovision of those goods and services. 
     I am well aware that there are theoretical problems with 
the part about why you would need some kind of exogenous shock 
to spending to achieve this.  As well as why there should be 
unused productive capaicty, or unmet productive potential.   
     But -- if you are going to oppose a policy prescription, 
at least oppose it as it is intended to work.   
     The intention is to make the MARKET dictate WHERE and HOW 
new investment is going to occur -- rather than designate some 
activities "investment" and "saving" (like playing around with 
the stock market or building vacation homes at the beach ....) 
and hope that the people who engage in those activities will be 
smart enough to take advantage of the tax break. 
     (And the market just might dictate that investment ought 
to be in human capital ...) 
     -- Mary Schweitzer