I guess it depends on how you define "work."
Will the GOP tax plan "work" to spur growth in the economy? Probably not, because the economy has already recovered. We're at or near full employment, the housing market has recovered, corporate profits are doing fine, and the stock market is at record highs. Cost of living is low, inflation is low, basically the economy is firing on all cylinders.
The GOP plan is based on a false premise - that the economy is weak. We can argue all day long whether tax cuts can spur a weak economy or lead us out of a recession, but the fact is that the economy isn't weak at all, and the recession is (relatively) a distant memory. We need tax cuts like a person who has recovered from an infection years ago needs another round of antibiotics.
I disagree. There's no question the GOP tax plan will spur economic growth.
The problem is the size of the result--the GOP is assuming a much bigger effect than really will happen.