paragraph: How shall we find the minimum of this (or any) loss function? Gradient descent is a method that finds a minimum of a function by figuring out in which direction (in the space of the parameters θ ) the function's slope is rising the most steeply, and moving in the opposite direction. The intuition is that if you are hiking in a canyon and trying to descend most quickly down to the river at the bottom, you might look around yourself 360 degrees, find the direction where the ground is sloping the steepest, and walk downhill in that direction.
answer: Gradient descent is a method that finds a minimum of a function by figuring out in which direction (in the space of the parameters θ ) the function's slope is rising the most steeply, and moving in the opposite direction.