If you conceive to build a perpetual motion machine then you will have taken the first step. The second (more difficult) step will be to conceive how a perpetual motion machine might actually work, or to come up with a plausible way of re-writing the laws of thermodynamics.

The point of the quote is not some wishy-washy "you can if you believe you can". Rather, it might be phrased better as "If you have the vision to see how something might be achieved and the drive to actually achieve it, nothing can stop you from achieving it".