There are four major factors driving the market. The factors are growth, trade wars, geopolitics and regulation of technology.
Each of the four factors has its own internal contradictions, in effect a binary outcome for each. This means there are 16 possible paths the market might follow (24 = 16). No wonder the market acts confused.
With regard to growth, the bulls expect a boost from the Trump tax cuts. They are also anticipating inflation due to strong job creation, rising labor force participation and a low unemployment rate. They expect interest rates to rise but consider this more a sign of economic strength than a cause for concern.
Strong growth is good for corporate earnings, and a little inflation is usually good for nominal stock prices, at least in the early stages. The bull case for growth is a curious mixture of the Phillips curve and the Laffer curve...