What is is. What isn't isn't.

This is the foundation of logic and it can be empirically verified in direct experience in any given moment.

There are many different branches of logic, e.g. quantum logic, linear logic, modal logic, intuitionistic logic, ..., but I don't know that any of these don't have modus ponens.

I'm interested - how long do you define a "moment"? Or is that subjective?

You already know how long 'now' is, you're living it. There is no possible deeper understanding of the 'now' other that the one that you are already living. When you try to define the duration of 'now' then that is done from within the context of the idea about time, which has nothing to do with this actual moment. This actual moment and the idea about time have nothing to do with each other, they don't intersect at all.

It can only mean that one of us is superfluous. Luckily, space is not at a premium, so neither of us will likely be recycled into something more useful

Or something very different than that. No worries though as it doesn't really matter very much unless you have a schedule to keep. Now is now, lunchtime is lunchtime and on occasion now is lunchtime and lunchtime is now. Other times, lunchtime is nearly now and you should start gathering ingredients. If you don't, you will be hungry and lunchtime-now will be unpleasant.

It might be important to note that what is not happening now is not happening. I hope that is your point.

Are you certain of this?

Of course not. It is quite possible that all of time and space is happening right now.

Of course, as far as my ability to experience things go, I am certainly not on the airplane that I got off of a couple hours ago, and as you read this, I will have already wrote it.

I meant it more as an encapsulation of what Ramana is trying to say about the human condition, not as a theoretical physics problem.

If A then B. If B then C. Therefore if A then C. This has a lot of useful applications.

But OP, you seem to be at:

If A than B. So, if A then B? Amirite? Yeah? Why?
This is not going to get you anywhere. You might be overthinking.

This is transitivity. Doubtless an important property, but OP was talking about modus ponens, which is concluding B from A and if A then B.

This is logical identity, a property so basic it can hardly be called overthinking:

http://en.wikipedia.org/wiki/Law_of_identity

^^^^
Modus ponens is a well accepted tool of logic, which has two main problematical areas. You must be sure whatA is, and that its consequential relation with B is genuine. If you can manage the same with B and C, you now have a chain of modus ponens, and this is not tranisivity.

Nor is the relation of A to B a question for the law of identity: that is a question of the relation of A to A, which is the first of the problems above.

My issue with OP's problem is that once you have established A and B, and that there is a consequent relation, then you can say that 'if A then B', which is merely a more economical way of saying what you have already established, and worrying away at this is overthinking.

On the other hand, if by naming something you suppose you have propogated an argument, you have been thinking badly, especially if you have mis-named the thing.

Concluding A -> C from A -> B and B -> C is transitivity. Concluding A -> B from A -> B is identity. But now I'm repeating myself.

^^^^
I don't think you are repeating yourself.

Could you explain ( in words) what you mean by 'concluding A -> B from A -> B is identity'?

Is this a superior, more economical description of identity than to say that identity is the question of the relation of A to A?

A -> B denotes "if A then B".

My understanding is that the law of identity states that X -> X, for any logical statement X.

A -> B is a logical statement so, as an instance of the law of identity, (A -> B) -> (A -> B).

'X -> X, for any logical statement X, is the law of identity'.

Or as I put it in English, it is a question of the relation of A to A.

Now, 'concluding A -> B from A->B' is not the law of identity, nor any law, as it is an action.

This really is an arid discussion. You seemed to have some objection to the argument of my first post, but rather than be plain what the problem is, you have been spraying basic logical formulae about at random, and inaccurately.

I'm off now, with a more visceral understanding of 'infinite regression'.

First sensible thing you've said.

Good.