+0
Does "whereby thou canst at the same time will that it should become a universal law" mean "whereby you cannot at the same time wish that it (the maxim) should become a universal law"?

Context:

Some philosophers, notably Kant, have tried to derive absolute
morals from non-religious sources. Though a religious man himself,
as was almost inevitable in his time, Kant tried to base a morality
on duty for duty's sake, rather than for God's. His famous
categorical imperative enjoins us to 'act only on that maxim
whereby thou canst at the same time will that it should become a
universal law'. This works tidily for the example of telling lies.
Imagine a world in which people told lies as a matter of principle,
where lying was regarded as a good and moral thing to do. In such
a world, lying itself would cease to have any meaning. Lying needs
a presumption of truth for its very definition. If a moral principle is
something we should wish everybody to follow, lying cannot be a
moral principle because the principle itself would break down in
meaninglessness. Lying, as a rule for life, is inherently unstable.
More generally, selfishness, or free-riding parasitism on the good-
will of others, may work for me as a lone selfish individual and give
me personal satisfaction. But I cannot wish that everybody would
+1
NL888Does "whereby thou canst at the same time will that it should become a universal law" mean "whereby you cannot at the same time wish that it (the maxim) should become a universal law"?
No. The reverse. "canst" is the old form of "can" that goes with "thou" ("you"). "thou canst" means "you can", not "you cannot".

Act only on principles that could be made universal principles.

If it's not a good idea for everybody to do it, then nobody should do it.

CJ