system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do lawyers need need certification, if the defendant, who isn't a lawyer, can defend himself?

If there's a precedent for a non-lawyer to defend, why does a lawyer need certification at all?
gpt
When you hire somebody to work for you, you want them capable of doing the job.  Let's say you find somebody on the street, and ask them for legal advice.  let's pretend the advice they give you is actually illegal.  If you take that advice to trial, and it backfires on you, you're the only one to blame.  The random person on the street can say whatever he wants to you, no matter how illegal it is, but it was your decision to follow it.

Now, instead of random people on the street, we have lawyers.  They have a piece of paper saying that they know the law.  So, if they give you illegal advice, and the judge asks you, "why did you do it", now you can say that a lawyer with a certificate, who should know better, told you to do this, and you trusted him because he has that piece of paper.  In this case, you wouldn't get in trouble, but the lawyer would.

Society demands that professionals, not just lawyers, have formal training and certification because it holds them accountable, not their clients, for any wrong doing.