Is having a bunch of the world's best thinkers and writers become lawyers (particularly corporate lawyers) a waste of human capital?

It's not just lawyers.  Come to the Washington, D.C. area and see how many really smart people are involved with public administration and public policy.  I'm talking about government employees, but also those who work for think tanks and trade associations and other lobbying groups.  There's a whole city full of them!  What if they were all actually making stuff instead?

It's a huge waste.  Saying that it's great to have a ton of lawyers is like saying that it's great to have a ton of accountants to interpret our ridiculously convoluted tax system.  Yes, given that the system is so complicated, we need lawyers, but really the question to ask is why is the legal system so complicated in the first place?  (Protip: it's usually JD's in the government who come up with the brilliant ideas to make the system more complicated) For our tax system, when we look at each individual piece of the tax code separately, it makes sense why each part is there.  However, when you realize that we have hundreds (thousands?) of these fun little tax quirks to keep track of, you have to ask who the genius was that decided to make everything so complicated?  Ok maybe everything is more fair by adding in infinite exemptions/deductions/etc, but when America spends 6.1 billion hours filing taxes each year, doesn't that make people think that the tax system just way too complicated? I think it's the same way with law and lawyers...yeah you can point to a single piece of legislation/regulation or whatever, and it'll make sense why we have that there.  But when you start adding ridiculous layers of time/money needed to navigate those regulations, as a society I think we should recognize that we're wasting a lot of human capital to navigate that mess.

It depends entirely on what those people do as lawyers. For example: Working tirelessly in a giant law firm doing litigation discovery or M&A due diligence = huge waste. Working tirelessly to free an innocent man or to convict a guilty one = not a waste at all.

The questioner should be sued for even suggesting that there are too many attorneys and that any of those fine legal minds are a waste of human capital. If anybody wants depose me for the suit, just contact me.

I'm not a Scalia fan and a "waste of human capital" is too strong.  It applies to a zillion professions: real estate agents, investment bankers and everyone else who is leaching off the transactions or misfortune of others.  That said, I'm mindful of his points.  Scalia said something about seeing all of these great minds before him thinking the could be out curing cancer or something (I'm paraphrasing).  When you say it like that, you at least get where he is coming from.  Society does not people who are focusing on actually making something.  The problem is, it is a complex world and people need help navigating through that world.

I think by definition of the law of supply and demand, there are the right amount of lawyers, at least practicing lawyers.  Like a rockstar engineer, a rockstar lawyer is worth 10-100x more than a standard one.  Actually maybe 1000x when the going gets really tough.

I don't think so. Law is how we settle disputes without resort to force or violence and maintain public order. That requires lawyers. There are legitimate complaints to be lodged about how lawyers practice and with what their clients do, but that's another matter. You wouldn't be happy if we got rid of all the lawyers.

When I read about the arrest of James Hansen, the scientist behind http://350.org, along within Daryl Hannah and http://en.wikipedia.org/wiki/Robert_F._Kennedy,_Jr. at the White House on February 13, 2013 during a protest against the proposed Keystone pipeline extension, I thought the protest was pointless. As long as there are buyers, there are sellers. They wanted to sell more oil simply because there were buyers. Oil buyers didn't have the technologies to produce renewable energy because they didn't have or couldn't attract enough engineers for operation and maintenance. This world is governed by incentives so you can't really blame people who act on incentives. If you want to tell people to stop doing something, you just can't tell them so but have to eliminate their incentives. To answer the question, Yes, it's a colossal waste. But you can practically do nothing about it.

What is a "lawyer"?  It's completely unwarranted to make such a generalization about lawyers.  Scalia interacts with a miniscule percentage of the profession, and probably has little idea of the pursuits the practice of law can actually encompass--or of the other ways in which knowledge and skills can be applied outside of formal practice.   People with a degree in law use their knowledge and skills in very  different ways to promote incredibly varied aims, including the  production of "things."   A degree in law is an incredibly useful tool in the modern age, where almost all transactions involve bureaucracy, regulation, and contracts.