A rival theory to explain common mutations is that they just happened to be present in a founding population and grew more frequent by chance.

It was an attempt to find concord in rival medical theories of the time.

It was only in 1869 that Rankine admitted the success of these rival theories.

A range of rival theories is considered next.

Following the Council, two rival theories emerged in the Church.

Facts do not go away when scientists debate rival theories to explain them.

It sometimes happens that two or more rival theories meet all of these requirements, which poses the problem of having to choose between them.

Ireland since 1919 had been governed under two rival political theories.

And iraq of course, although there was a rival theory that the usa were after a permanent military base not oil.

So the rival theories began to lean closer together.