• There is one reality that exists apart from what human beings think and feel about it.

• This reality is made up of kinds of things which have properties and stand in relations.

• Some of these things, properties and relations are invariant, at least for some time, and therefore predictable.

• Human beings form part of that reality and have experiences and fantasies about it that originate in it.

• All living human beings have beliefs and desires about many real and unreal entities, that are about what they think is the case in reality and should be the case in reality.

• All living human beings have very similar or identical feelings, sensations and beliefs and desires in many ordinary similar or identical circumstances.

Some assumption like natural realism is at the basis of human social interaction, at the basis of the law, and at the basis of promises, contracts and agreements, while the last of the assumptions I used to characterize Natural Realism amounts to an assumption of a shared human nature.

We shall assume Natural Realism is also at the basis of philosophy, at least initially, firstly, because we must assume something to conclude anything; secondly, because even if we - now or eventually - disagree with Natural Realism it helps to try to state clearly what it amounts to; and thirdly, because it does seem an assumption like that of Natural Realism is involved in much human reasoning about themselves and others, and about language, meaning and reality.

Finally, since this implies not only a logical and rational approach to knowledge but also an empirical and scientific approach, we assume, to start with, and until we have found better rules, next to logic, Newton's "Rules of Reasoning" in his "Mathematical Principles of Natural Philosophy".