Sir

Can we comprehend the ideas and thoughts of other beings? The scientific literature from a variety of fields, including psychology, sociology and ethics, suggests that we can. The methodology used in the disciplines of genetics, psychology, animal behaviour, sociology, history, public understanding of science, and religious studies — to mention only a few — can and should be collected to design an integrative approach to understand the extent of human ideas. Readers are invited to a meeting in Japan on 15 February 2003 to start such a project (see http://www.biol.tsukuba.ac.jp/~macer/index.html).

If we define an 'idea' as the mental conceptualization of something — including physical objects, an action or sensory experience — then the number of objects in the universe of a living being is finite. Both the number of possible choices for action and the sensory states of animals are finite. In that sense we can expect to be able to count ideas. The initial methodology could separate classes of ideas, as follows: (1) conceptualization of physical objects; (2) psychological meanings of images associated with objects (such as colours); (3) memories; (4) plans for short- and long-term future; (5) intention to modify one's behaviour; (6) intention to modify behaviour of surrounding beings and the environment; (7) sensory states such as pain, pleasure, libido; (8) inhibition of a response based on immediate evolutionary benefit, for example, memes; and (9) interactive conceptualization of ideas in a community-based response.

I propose a 'mental mapping project' to explore similarities between cultures and communities, both at the individual human level and as members responding inside biological communities. There are implications for cultural identity. How should the culture that tries to maintain its uniqueness face up to the reality that the full range of idea diversity is found in every culture? Idea diversity is found in almost all cultural groups, excluding those formed to promote particular political aims, such as those who fight for or against the right to choose abortion or euthanasia.

The universality of ideas is important for the development of global society, when we're faced with dilemmas such as whether to have common international guidelines to regulate the use of new biotechnology, for example, or of assisted reproductive technology using cloning. It is time to start thinking scientifically about this in a coordinated way.

Although the human mind appears to be infinitely complex, and the diversity of humankind and culture has been considered vast, I would suggest that the number of ideas that human beings have is finite. Hence my call for a project to map the ideas of the human mind. We already have the means to embark upon a human mental map with the goal of describing the diversity of ideas a human being makes in any given situation or dilemma.