My understanding of trickle down economics is that you get more economic activity by putting a dollar in the hands of the bottom 10% than the top 10%, which makes sense since the propensity to consumer is higher at the bottom. By investing, the top % supports invention and innovation. By consuming, the bottom % validates those inventions and innovations that are worthwhile, versus those that are worthless. Both functions are required in order to keep the economy humming along producing and consuming new goods and services at a rapid pace. There would seem to be some function which maximizes the utility of each group in their respective roles. That's what I would want tax policy to reinforce.