The senses we possess have evolved differently for each individual, depending on the environments of our ancestors, and we are only equipeed to find out things that were necessary to their survival. Truth is therefore not absolute, and each of us lives in a somewhat different world.

To draw conclusions about everything that affects us, and not merely scientific facts, we have to start the drain of reasoning from the subject ("myself") and work outwards. That is the right approach to non-scientific issues like emotions, motivation, love between parents and children, and relationships with other people, whch are the most important concerns of humans.

Shennan is a medical doctor whose career dealt with tuberculosis in developing countries, mainly in Africa. For more than 30 years he has been concerned about the technology spiral and its effects. Since retirement in 1992 he has read widely on human evolution and culture and set out to draw together the work of these authors and that of the specialists who have written on the many other disciplines affecting people, so as to achieve an overview of the present human predicament.

Also by Douglas H. Shennan:
Evolution and the Spiral of Technology