According to Weisman, large parts of our physical infrastructure would begin to crumble almost immediately. Without street cleaners and road crews, our grand boulevards and superhighways would start to crack and buckle in a matter of months. Over the following decades many houses and office buildings would collapse, but some ordinary items would resist decay for an extraordinarily long time. Stainless-steel pots, for example, could last for millennia, especially if they were buried in the weed-covered mounds that used to be our kitchens. And certain common plastics might remain intact for hundreds of thousands of years; they would not break down until microbes evolved the ability to consume them.

Q: If human beings were to disappear tomorrow, the magnificent skyline of Manhattan would not long survive them. Weisman describes how the concrete jungle of New York City would revert to a real forest.

A: “What would happen to all of our stuff if we weren’t here anymore? Could nature wipe out all of our traces? Are there some things that we’ve made that are indestructible or indelible? Could nature, for example, take New York City back to the forest that was there when Henry Hudson first saw it in 1609?

“I had a fascinating time talking to engineers and maintenance people in New York City about what it takes to hold off nature. I discovered that our huge, imposing, overwhelming infrastructures that seem so monumental and indestructible are actually these fairly fragile concepts that continue to function and exist thanks to a few human beings on whom all of us really depend. The name ‘Manhattan’ comes from an Indian term referring to hills. It used to be a very hilly island. Of course, the region was eventually flattened to have a grid of streets imposed on it. Around those hills there used to flow about 40 different streams, and there were numerous springs all over Manhattan island. What happened to all that water? There’s still just as much rainfall as ever on Manhattan, but the water has now been suppressed. It’s underground. Some of it runs through the sewage system, but a sewage system is never as efficient as nature in wicking away water. So there is a lot of groundwater rushing around underneath, trying to get out. Even on a clear, sunny day, the people who keep the subway going have to pump 13 million gallons of water away. Otherwise the tunnels will start to flood."

Was the Universe before the Big Bang of classical nature, described well by a smooth space–time? Or was it in a highly fluctuating quantum state? This is one of the most basic questions that we may ask once it is accepted that there was something before the Big Bang. Loop quantum gravity applied to isotropic models has shown that the quantum evolution of a wavefunction extends through the Big Bang. Although a general demonstration is still lacking, this may suggest that calculations, and possibly future indirect observations, may allow us to see the Universe as it was before the Big Bang. Here, we analyse an explicit model with a pre-Big Bang era, indicating limitations that would imply that it is practically impossible to answer some of our questions. Assumptions (or prejudice) will remain necessary for knowing the precise state of the Universe, which cannot be fully justified within science itself.

Joel Spolksy has a good article on management books in which he quotes Michael Lopp:

The disagreement reminded me there are two distinct personalities when it comes to devising solutions to problems: Incrementalists and Completionists.

Incrementalists are realists. They have a pretty good idea of what is achievable given a problem to solve, a product to ship. They're intimately aware of how many resources are available, where the political landscape is at any given moment, and they know who knows what. They tend to know all the secrets and they like to be recognized for that fact.

Completionists are dreamers. They have a very good idea of how to solve a given problem and that answer is SOLVE IT RIGHT. Their mantra is, "If you're going to spend the time to solve a problem, solve it in a manner that you aren't going to be solving it AGAIN in three months."