Moore's Law was really not intended as a statement about computer science but simply a rule of thumb about the progress of chip-making during a specific period based on an observation made by Gordon E. Moore, one of the founders of Intel. In a paper written in 1965, he noted that the number of transistors that could fit in an integrated circuit seemed to double every year. This was somewhat of a self-fulfilling prophecy as he made it a goal for research and development at Intel.
The law was first revised in 1975, when the doubling period was increased to two years. In approximately 2013, it became obvious that the size of transistors could no longer shrink in accordance with Moore's law due to two issues of basic physics. First, the size of transistors runs against a hard limit in terms of the size of atoms. Second, at the current (2016) time, making transistors smaller would increase the probability of quantum tunneling, making them less reliable.