Does Halacha Change?

I saw this post at Wolfish Musings which reminded me of something I had once learned. At first I commented on the woman learning Gemara part, and I have to say it is a really amazing feeling to see something from the Gemara and actually know what it’s talking about and where it came from. Ex: Lakewood Falling Down’s Post. But now I’m going to comment on a different part of the Wolf’s post.

The Wolf asks:

“The question at hand was whether it's possible that rabbinical statements could be influenced by the environments in which the people who uttered them lived in, or are they delivered in a vacuum (so to speak) and are always valid at all times and under all circumstances.”

My Answer (As typed up from my seminary notes from R’ S.):

There are many things in Halacha that seem to be contradicting and you start to wonder if maybe Halacha changes as time goes on or if the Rabbi's were wrong.

Here are some Examples:

1. If a cat attacks and animal, that animal becomes treif from the venom poisoning it.
   Q: But there's no Venom in a cat.
   A: Cats that go into the garbage get infections, so Halacha doesn't have to change, there's just a different reason.
   
2. On shabbos you could kill lice, you can't kill stuff that reproduce, lice comes from dirt.
   Q: But its impossible that something comes from nothing.
   
   A: 1679 - Pachad Yitzchak said chachamim made mistake about not being able to kill lice.
   All Torah was given to Moshe, how to apply it was given to the Chachamim, Moshe said you could kill lice, we find reasons based on knowledge and apply it, the reason could be wrong, but Halacha is not wrong.
   
   Chachamim knew reasons aren't good, but people would only listen if there is a reason to believe to accept the Halacha. It’s a reason that people believed in at that time.
   
   There are Many reasons for halacha, not just 1 reason, but it doesn't say all the reasons.
   
3. Bird grows from tree and needs shchita
   Q: But its not possible that a bird comes from a tree.
   A: A bird coming from a tree is just a metaphor.

• A) Chachamim had superior knowledge -- Ruach Elokim, even if scientist say that its not true.
• B) Overtime nature has changed, we can't use their refuahs cause we changed, were not the same, certain halachos could change.
• C) It could be we misunderstood the chachamim, so we can't say they’re making mistakes.
• D) They spoke in metaphor's, not everything is meant to be taken seriously.
• E) Chachamim got knowledge from scientist, then they made Halachos, now Halacha changes.

Examples:

1. Snake stays pregnant for 7 years. Now it takes only a few years, scientist did research and found garter snake is pregnant for 7 years. So it could be that in the time of the chachamim there was a snake that was pregnant for 7 years.
   
2. Salamander oil if you smear it on your body it will become fireproof and won't burn, if there's a continuous fire for 7 years then a salamander will come from it. There are different types of salamanders.