I understand the logic behind belief in G-d. However, in trying to become more observant I find that I am wrestling with two points.
1. Since the Torah contains the absolute truth, its laws should apply in all times and places. But the way of life of an observant Jew in ancient times would not be considered an observant lifestyle today (for example: polygamy, slavery, no Kipah).
2. Since the Torah contains the absolute truth its laws should apply to all of humanity.
These are two areas in which I can't see the logic behind the traditional beliefs. I am hoping you can address these points.
I very much appreciate your thoughts on this, Andy

Answer: 

Two great questions!

1. Torah is absolute truth, but people's lives aren't.

The Torah therefore permits, and in some instances obligates, the Torah scholars throughout the ages to create fences and ordinances AROUND the Torah, in order to keep Torah Judaism intact.

This system is very complex and too broad for one e-mail, but in a nutshell: if the Torah forbids one from doing something, it can never be permitted. But if the Torah says you MAY do something, it doesn't mean you HAVE to. Thus if one doesn't do it, he is not contradicting the truth of the Torah. So if a new issue should arise that makes a particular permitted thing problematic, the Jewish leaders of any given time have the right or obligation to forbid it (Example: forbidding polygamy or slavery, since people could no longer handle it properly).

It is only the things that Torah did not forbid or mandate that can be changed

In other words, Torah's laws apply in all times and places. It is only the things that Torah did not forbid or mandate that can be changed.

2. Again, Torah is absolute truth, but people's lives are different.

Absolute truth says that 2+2 is 4. It will never be otherwise. Unless you have 2+3, then the result will be 5.

If all of creation was one identical object with the same objective, the Torah would apply universally to all of humanity, but we are not created identical and our objectives differ.

That is why the Torah has different rules for Priests, Levites, men, women, children, Jews, non-Jews, free people, slaves, healthy people, ill people, etc.

Because the Torah is absolute truth it can be one system that is applicable to all people. Each as it is fitting for them.

[Ed. note: You might also want to read about 'Why aren't we offering sacrifices any more?']