Nonetheless, an argument from common sense can be made based on our own observational context. For example, neurologically speaking, there is a wealth of evidence to illustrate that genes have an immense impact on the final structure of the brain, and thus on behavior. Schizophrenia is an obvious example of this. Logically, though, there is also abundant support for Dawkins' thesis. Roughly, an argument can be shown to be logically viable if its conclusions can be reasonably drawn from its suppositions based on the available evidence. This is abundantly the case in the Selfish Gene, wherein Dawkins (1976) draws on all the existing evidence on evolutionary theory and the development of life, including the mechanism of natural selection (p. 48) and DNA as...

22-23). The evidence that Dawkins provides is, quite simply, sufficient to support his argument that the gene should be perceived as the primary building block of life and evolution, just as the atom is the primary building block of all matter. Because of the evidence provided, and the logical claims that follow, it is easy to support Dawkins' thesis that the gene is the basis for evolution and that behavior can be, to some degree, shown to have a genetic basis. Because genes that do not promote survival of their host "machine" will quickly die off, it logically stands that any gene machine still in operation -- such as human beings -- will contain genes that favor behaviors that improve their own chances for survival. That life exists at all through this process of natural selection is evidence enough that the gene must be perceived as the basis for evolution and for behaviors that favor the advance of individual genes.
References

Dawkins, R. (1976). The Selfish Gene. New York: Oxford University Press.

Hergenhahn, B.R. (2005). An Introduction to the History of Psychology. 5th ed. Wadsworth-Thomson Learning.