It means there are only two possibilities.

也就是说只有两种可能
Either you've got some fire and it will be hot,

要么有火并且是热的
or the fire has been destroyed, it's been put out.

要么火被熄灭了
Those are the only two possibilities.

这是仅有的两种可能
You either have--

要么
If heat is an essential property of fire,

如果热是火的基本属性
either you've got some fire and it's hot,

要么有火并且是热的
or the fire no longer exists, it's been put out.

要么火不存在了它被熄灭了
There's no third possibility of a non-hot fire, of a cold fire.

没有第三种可能出现不热的火冷的火
So, if you've got the claim that

所以如果你断言
life's an essential property of the soul,

生命是灵魂的基本属性
only two possibilities:

那么也只有两种可能