That is a complicated question. The simple, but unsatisfying, answer is, “sometimes.”
Basic economic theory says that when a free market is in equilibrium, that is, when the market is supplying the exact amount of a good that is demanded, then introducing a tax into that market will distort it and mean less overall economic output. The difference is called “deadweight loss.” Therefore, in general, reducing taxes on goods and services can, in cases where the market would otherwise function properly, help the economy.
BUT…economic theory also tells us that there are such things as “market failures.” These are situations in which the market does not function properly and there are many reasons why this can occur. In the cases of market failures, imposing a tax can actually fix the problem, bring the market into equilibrium, thereby improving overall economic output.
There is one other factor to consider (I’ll apologize here for the long post)...what do we do with the revenues that taxes raise? If those revenues are “invested” in programs and projects that improve efficiency and productivity, or reduce societal ills that tamp down economic output (such as crime, illiteracy, disease, etc), then tax revenue can serve as an important part of a long-term growth strategy.
I suspect that you wanted some take on the current situation and whether cutting taxes would help right now. Again, the answer is, “it depends.” Will it help to cut the top income tax bracket from 35% to 30%? No, probably not. That kind of tax cut will put more money into the hands of consumers who are likely to save at least a portion of that tax cut. Savings, in general, are not stimulative. However, cutting taxes for low-income workers could provide an immediate boost, as those folks are much more likely to go out and spend those dollars right away.