'Motive' power?

The point of all philosophy is to motivate you in the right direction. (What is the right direction? The direction that the philosopher prefers, of course. I mean, really, do you expect a Karl Marx to teach you how to become a Warren Buffet?) Quite naturally, they have a very high opinion of motivation...as in, the importance of your being motivated to do what you set out OR what they push you to do.

And, thus, Tiru says...

Pariyadhu koornkottadhu aayinum yaanai verooum pulithaak kurin - Tirukkural

Despite its large body and sharp tusks, the elephant fears the attack of a tiger - Loose Translation

Despite its seeming advantages over a tiger in battle, the elephant fears the attack of the tiger because (and the because is implicit) the tiger is emboldened by its inner motivation (to eat? Yeah, that primarily). It is its motivation and, thus, its enthusiasm that makes it the stronger warrior than the seemingly invulnerable elephant.

In other words, if you can attack the obstacles in your route to success with unflagging enthusiasm, you will defeat them. No matter how insurmountable they appear when you first encounter them. And THAT unflagging enthusiam comes out of the strong motivation to reach your goals, no matter how difficult they seem at first. If, however, you slink away when you see the size of the elephant and the sharpness of its tusks...

So, you see, the extent of your motive power is determined by the power of your motivation.