THE PAST EVOLUTION OF MAN 89 



not only in relation to organic but also to social 

 and mental evolution. The generalisation which 

 has been reached in so many spheres, is that 

 intermediate types tend to disappear. Now we must 

 beware of confused thinking, which is not infre- 

 quently to be met in the neighbourhood of this 

 assertion. It will not do to call all (assumed) types 

 that have disappeared intermediate, and then to say 

 that intermediate types tend to disappear. Other- 

 wise we are guilty of advancing, as a truth, what 

 the logicians call a " verbal proposition," which 

 really says nothing at all. But by intermediate 

 types we mean types representing the transition 

 from one mode of life, or one environment, to 

 another. Such types naturally tend to disappear, 

 for they are not well adapted to any environment : 

 they are " neither fish, flesh, fowl, nor good red 

 herring." The types that persist are those which 

 are definitely adapted to a constant environment. 

 The marine mammals, such as the whale, were in 

 all probability driven to the water by the fierce 

 competition on land, where the mammalian family 

 must have originated ; but we find no living re- 

 presentatives, nor indeed any remains, of the hard- 

 driven types which endeavoured to eke out an 

 existence on land when they could and in the 

 water when the land was denied them. Such a 

 type, properly adapted to no environment, could not 

 persist. 1 



Leaving this digression, which deals with a fact 

 of some importance in relation to one of the 



1 Similarly the batsman who plays neither " forward " nor 

 M back/' but the " half-cock stroke," is apt to disappear — bowled. 



