Gould takes issue with the way Wilson defines a reductionist approach as "solving" matters by breaking them down into their constituent elements. Even in science, emergent properties can't be explained using this approach: defining water as H2O tells us nothing about the property of liquidity, because it's not contained in the constituent atoms. So a reductionist approach is going to be useful in some sense, but the notion that it's sufficient for explaining complex human cultural phenomena is simply not true.
This seems a bit backwards to me. The emergent propeties are only explained through a reductionist approach. When we look at water macroscopically, we have to take most of its properties simply as givens - as brute facts about the way water is. Water has a high surface tension and cohesion, and we can use that fact to explain some of its behaviour.
To explain why water has these properties, reductionism is the only solution, since water's properties are emergent properties of the properties of the molecules that make up the liquid (it's something to so with hydrogen bonds - it's been a long time since science at school!).
Well that's convenient, then. Gould's dead, so I wouldn't get very far arguing with him
(And the emergent properties are defined not by the constituent atoms, but how the atoms interact in the water molecule.) Gould wasn't saying reductionism is never useful, but as the guiding principle in uniting science and the humanities, it's inadequate.
I picked up on your water example because it's the only real concrete thing I've noticed you mention, and yet it seems such an odd choice because it demonstrates the opposite of what you appeared to want it to. The best way to understand the properties of liquids is reductionism.
Reductionism gets an unfairly bad rap, I feel. Every now and again you come across someone announcing that it's a thing of the past, and people who cling to reductionist ideas are intellectually unreconstructed relics, but it seems to me that reductionism remains the way forward. The properties of any complex system are always the product of the properties of its constituent parts (or as you put it more accurately, generally the way these constituent parts interact).
Now how reductionist we want to go depends on the level of explanations we're seeking for any phenomenon. It's not necessary to discuss the behaviour of individual atoms of H2O to explain the functioning of a steam engine - you can just rely on known properties of water, but if you want to explain why water has those properies, reductionism is the only way to do so.
Aside from this one substantive claim, which seems to be wrong, everything else appears to be a vague lament about modern culture.