Consciousness = Name-and-Form.
Name-and-Form = Consciousness.
There, courtesy of the Buddha. It's really a nasty loop... and focusing on just one side (i.e., materialism, or basically, the name-and-form) doesn't really solve it (unless you're willing to base your life around this kind of delusion). It invariably leads to dukkha.
Why? Because there will always be people who would be more than able to logically assert the existence of the consciousness against you. And vice-versa... if you say that it's all consciousness, then there will always be people who're more than able to logically assert the existence of forms.
This is what causes the (endless) rebirths of discussions. The trick to this whole problem, really... is just to see through this loop (i.e., anatta).