Science goes from the part to the whole. The method he used is inductive. Progress in science is like a snowball. One development triggers another, a different development provides the discovery of the missing and inadequate. This is a process job. It is a matter of trained team, equipment, time and money.
Of course, when he says quasi-science, he is not talking about pseudo-science. It means philosophy, which includes science and other elements other than science. The method of philosophy is different from science. One is inductive and the other is deductive. Philosophy reaches the part from the whole and moves from absolute truths. Science explains things in a positive way, philosophy in a speculative way.
In this way, Nice leads from the longer one to the shorter one. He is of the opinion that science should walk in its own way and progress, but many things should be solved and enlightened without losing time with semi-science. In other words, he believes in the power of the philosophy of science and the results it will bring.