Question: What does an ethical vegetarian do about wearing leather tefillin?
Jewish law requires that tefillin be made from the skin of a kosher animal. So, non-leather tefillin are not a possibility for someone who wants to fulfill the mitzvah of tefillin.
There are, however, a few of mitigating issues that may make the use of leather tefillin more palatable for the ethical vegetarian:
1. No animal is killed for the purposes of using its skin. That is, leather is a by-product of the meat industry. From an animal welfare perspective, leather is still problematic because it is a profitable part of the cattle raising industry – a profit which motivates cattle production – but sometimes knowing that an animal wasn't killed for the purposes of tefillin helps ease the concern of the potential end user.
2. The leather must come from a kosher animal, but is not required to come from an animal that was killed according to the Jewish laws of slaughter. In theory it is possible to make tefillin from an animal that dies of natural causes. For reasons of logistics surrounding the attainment of the skin of an animal that dies of natural causes, to my knowledge there is no commercial manufacturer that produces tefillin from an animal that dies of natural causes. (Interesting note: most leather used for tefillin in Israel does not come from animals that were slaughtered according to Jewish law – it comes from non-kosher beef producers in Europe).
3. It is important for a vegetarian to know that the purchase and use of leather tefillin is much less problematic – from an animal welfare perspective – than the consumption of dairy and eggs. Abstinence from meat consumption does not ensure a diet that is not directly linked to the industrial killing of animals.
I frequently meet folks who do not daven the musaf amidah because they do not like the references to the sacrificial worship that took place in the Temple. When I point out to them that the number of animals killed in the Temple was exponentially less than the current number killed for the production of human food products it causes the listener to re-evaluate, a) their assessment of the meaning of the musaf amidah, and, b) their own dietary practices.
As a note: when animal sacrifice was institutionalized it was a direct result of the high value and worth placed on animal life. A return to the sacrificial system – which is the essence of the musaf amidah – only makes sense if giving an animal's life to Gd is seen as a 'sacrifice' of something valuable of the giver – a day I look forward to.
4. When I use my leather tefillin I say to myself that it is a compromise that I make due to my commitment to Judaism, Torah and Gd. If I only partake of the elements of our tradition that appeal to me, then I'm not observing Judaism as much as I'm observing 'Me-ism.' There is humility for me that comes with doing something in the name of Judaism that takes me out of my comfort zone. Just like a commitment to someone else with whom I am married – and I do many things out of my commitment to that person that I'd prefer not to do – similarly, my commitment to Gd and Torah has me doing things that I would choose not to do were I given the choice.
5. In line with the above reason of humility, perhaps I'm wrong in my opposition to using animals for tefillin. Perhaps our tradition knows better than I do about what it means to elevate the life of an animal by using it to partner in bringing holiness into the world by way of tefillin.... I will continue to use leather tefillin as a recognition that perhaps Jewish tradition knows better than I do about matters in the world.
Finally, I encourage tefillin wearers to seek to refurbish older sets of tefillin. In addition to the sentimental value of giving life to an unused set of tefillin, refurbishing them will greatly reduce (maybe eliminate) the harm to animal welfare that could be connected to fulfilling the mitzvah.