23:38
That makes a lot of sense. I guess now I really just am having an issue understanding integration in general. So let $M$ be an $n$-dimensional manifold, $\gamma:[0,1]\to M$ be a curve, and $\alpha$ some 1-form on $M$. So we have that $\int_{\gamma([0,1])}\alpha = \int_{[0,1]}\gamma^*\alpha$. Once I'm here, how do I make the jump to $\int_{[0,1]}\alpha(\gamma^*(s))ds$.
I understand the definition of the pullback, by pushing forward tangent vectors, but my confusion comes from how do we show that $\gamma^*\alpha=\alpha(\gamma'(s)) ds$. Why does plugging in a unit tangent vector give us the proper real valued function in front of the 1-form $ds$?
Nevermind, I figured it out now. Sorry about that and thanks @BalarkaSen and @Juan. I just realized that if I take any tangent vector $v\in\mathbb{R}$ that we have that $\gamma^*\alpha(v)=\alpha(\gamma'(v))$ and since $dv(v)=1$ we can find the real valued function in front of $dv$ or $ds$ simply by plugging in any "test" vector!