If a being suffers there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that its suffering be counted equally with the like suffering - insofar as rough comparisons can be made - of any other being. So the limit of sentience is the only defensible boundary of concern for the interests of others. To mark this boundary by some other characteristic like intelligence or rationality would be to mark it in an arbitrary manner. Why not choose some other characteristic, like skin color?

I know of a number of people who are successfully earning to give. That isn't for everyone but for those with the ability to earn a lot of money and the character to resist the temptation to spend it on themselves, it can be a great way to do good.

Torturing a human being is almost always wrong, but it is not absolutely wrong.

According to the Dominant Western tradition, the natural world exists for the benefit of human beings.

At present scientists do not look for alternatives simply because they do not care enough about the animals they are using.

As we realize that more and more things have global impact, I think we're going to get people increasingly wanting to get away from a purely national interest.

Racists violate the principle of equality by giving greater weight to the interests of members of their own race when there is a clash between their interests and the interests of those of another race. Sexists violate the principle of equality by favoring the interests of their own sex. Similarly, speciesists allow the interests of their own species to override the greater interests of members of other species. The pattern is identical in each case.