[carabiner]

All mammals rape. And murder, and steal. Dolphins torture each other. You don't think it's all sunshine and rainbows in the wilderness, do you?

[dragonwriter]

> All mammals rape

2. John does not rape.

3. Therefore, John is not a mammal.

[shard]

1. ∀ Species ∈ Mammal, ∃ at least 1 member of Species that rapes

2. John does not rape

3. ∴ John is not the raping member of a Species of Mammals

Pardon any misuse of symbols, it's been a while.

[dragonwriter]

So, the first member of any mammal species must, ipso facto, be a rapist?

[bigbubba]

What would the 'first' of a species be, in an objective sense? As I understand it, speciation is a gradual process. Trying to pin down exactly where the change occurs is like trying to pin down precisely where a rainbow gradient shifts from green to yellow. You can pick a point and declare that to be the demarcation line, but discrete categorization in this way seems inherently arbitrary.

Even seeming straight forward metrics like "can they produce viable offspring" isn't so black and white, since between 'yes' and 'no' exists a continuum of 'maybe's. In very rare cases even horses and donkeys can have fertile offspring, e.g. mules that aren't mules (the typical infertility of mules has lead to the occasional use of the term to describe any infertile hybrid.)