Trying to fine tune a philosophical argument to show that family members will be lining the streets demanding equal marital rights is a non-sequitur. How about you concentrate less on the slippery slope and more on actual problems that you feel will result from gay marriages.
Show me what harm has been done.
The problem with assuming a “sentience” perspective on harm is that it restricts your definition of harm to that which you palpably feel to be harm.
In the case of a spouse being cheated on, you have a difficult time explaining how harm could have occurred if the cheated on spouse is not aware of the harm.
A frog in a pot slowly being heated is never aware that its “goose is being cooked” because its sensory system is slowly being compromised.
Likewise when morality is slowly being compromised and replaced by a requirement to “feel” or be aware of harm in some sensory way, a moral being could have its “goose cooked” in the very fact that its moral sensibilities are being compromised and replaced by a kind of gross moral hedonism.
The frog in the pot does not realize its long term interests are being rapidly lost precisely because its sensory system is being damaged in a manner that makes it inefficacious for warning the frog. Reliance on its sensory system alone as an indicator of harm is what makes the frog vulnerable to a disabling of that system.
Human beings have, beyond sentience, reason as a method of determining real harm. We don’t need to rely solely on sensory awareness. We can judge harm to our interests even where that harm is not palpable in some sensory way.
The spouse being cheated on is being harmed because her/his interests - in a relationship that s/he has totally committed him/herself to on the assumption that the other person has as well - have been compromised.
That is harm that doesn’t even register on your metric because your calibration requires some form of palpable harm to be felt or sensed. This is an indicator, by the way, that your metric for determining harm is grossly inadequate.
I would argue that your “harm must be sensed” requirement, by itself, is an indicator that your moral senses are compromised. You only know or aware of harm when it, literally speaking, comes up and bites you on the behind. Absent a chunk being physically taken out of your backside, you have no explanation for or awareness of a great deal of what constitutes real harm.
The fact that “gay” individuals rely totally on sensory based hedonism to define what makes them who they are belies the fact that they have done harm to their own interests by replacing real long-term, though intangible, moral interests with fulfillment of pleasure seeking.
Interests such as having a happy marriage, a wonderful family with responsible, well-adjusted children, etc. are compromised by an insistence that their interests must be based upon uncompromised satisfaction of pleasure/emotion, conveniently forgetting that happy marriages and families are made by hard work, sacrifice and eschewing self-interest for the sake of others.
A moral position that says, “My pleasure satisfaction will be my prime focus and any moral principles will be subordinated to that end,” will hit a conflict wall very quickly.
Again, the real harm is one of compromise to moral formation / fine tuning that will end up leaving the hedonistic individual with a moral disability. Like the frog in the pot, their “harm meter” will be slowly disabled precisely because they cannot transcend their own emotional/sensory state to recognize real harm when it faces them. Their sole indicator for harm can easily be “stewed” such that harm recognition (their own discomfort) will be deceptively unable to warn of real danger.
A culture where mothers casually kill their own babies by the millions, sex and children sought as commodities, and pleasure fulfillment is the principal motivation for action is a culture that is on the verge of being “cooked” - just very oblivious to that fact.
Gay marriage will likely not do much more harm to our culture, the harm has already been done - to marriage, to moral sensibilities and to individual consciences. Gay marriage is simply the buzzer alerting all that the frog is cooked and ready to be devoured.
