Young earth creationism: reductio ad absurdum

I've come up with yet another reductio ad absurdum argument against young earth creationism.  At least, it's new as far as I know.  I welcome references to existent instances of this argument, as well as corrections and suggestions to improve it.

Here's the argument.

1. Creationists say the earth is as old as the bible says it is: about 6,000-10,000 years.  (We'll say 10,000 for our purposes here.)
2. There are things on this earth, both natural and artificial, that are much older than 10,000 years.
3. If both (1) and (2) are true, as creationists tend to admit, then god must have made the earth with things in/on it that appear older than they actually are.  That is, god made the earth 10,000 years ago, with hundred-million-year-old fossils on it.
4. If (3) is true, then we cannot trust our senses, so there's no way to know anything external to one's minds.
5. The bible and god are things external to one's mind.
6. Therefore, there is no reason to believe the bible and god, as both these are entities external to our own minds.
7. Thus, starting with a creationist belief in god and in the bible, we can argue to the conclusion that we cannot believe in god and the bible.

QED

Step (2) deserves a little attention.  One might argue that the dating methods of scientists are wrong, and that things are actually younger than they seem.  If this were the case, then either (a) geologic history must be compressed to fit a 10,000 year period, or (b) the dating methods are so utterly flawed that there's no connection at all between their results and the actual ages of things.

Neither of these options makes sense.  If the first is true, then ancient events would have actually occurred during our lifetimes - which they didn't, or we'd have observed them.  If the second is true, then we cannot trust any observations at all, which means we cannot believe anything we perceive, including the bible and god - essentially the same as step (3).  This is in form the same argument as in step (4), which I discuss next.

So this means that the only reasonable interpretation a creationist can make is that the earth is young and has very old things on it.

The guts of the argument are in step (4).  Step (3) tells us that our direct and indirect observations cannot be trusted, regardless of how solid that observation may be.  For instance, we cannot trust radioactive carbon dating, which is calibrated to work well to as far as 50,000 years into the past. Likewise with other radiometric dating techniques that are used to date older things, like the earth itself.  We cannot trust archeology either, nor any of their discoveries.  Nor can we trust evolutionary biology.

Now, if there were a source of information that clearly indicated which observations we could trust and which we couldn't, we might be able to investigate this further.  But there's nothing in the bible, nor in any other scripture, nor in any other document of roughly the same age, that indicates the fossil record and related scientific knowledge was demonstrably wrong back in the time when the bible was new.  That is, no one in biblical times knew about fossils and ruins, and we have no way at all of knowing which of our perceptions and observations are right and which are wrong.

Indeed, using this reasoning, god may have created the universe just this morning, and everything else you think you remember from the past was just part of his divine plan that he built into the universe.

Now, some fundamentalists advise us that they can be trusted to guide our decisions on what observations are and aren't correct, but they cannot decide amongst themselves who of them is to be trusted, nor do they propose any justification to make even a moderate skeptic accept their claims. I think that a reasonable claim would be, for instance, correctly predicting events based on godly/creationist principles such that their record indicated statistical significance.  Unfortunately, it seems that their record at predicting things is wrong, and wrong in a very statistically significant way.

So, without the means to determine which, if any, of our observations are correct - and no such means is forthcoming - there is no choice but to believe none of them.

Step (5) is also important in that it identifies the bible and god as entities that are external to the human mind and thus within the realm of perception.  It's obvious that the bible is external to our minds.  Children, for instance, have no idea what the bible is because it's a book.  It is clearly external to their minds - to everyone's minds.

Superficially, it's somewhat trickier to deal with the notion that god is external to our minds.  After all, if god is really god, and it created everything, then it rather makes sense that we'd all have some built-in sense of god.

But this isn't so.  For one thing, there are many people on this earth who have never even heard of any god, let alone the christian god of these foolish creationists.  For another thing, if god exists, and existed before we did, then it must be external to us.  And finally, there are many of us who, having heard all about god, find nothing within us that seems of god.  All these things together indicate clearly that god, if it exists, must be external to our minds.

Overall, I think this argument is pretty reasonable.  What do you think?