  An advantage shared by learning-based theories and holistic theories of desire is that they are, in a natural way, able to hold that the strength of a desire can be a constant even while the effect of the desire on action, feelings, or thoughts seems disproportionate to the desire's strength. In the case of learning-based theories of desire, so long as there is a merely causal relation between the learning signal and the ordinary signs of desire strength, there is no contradiction in holding that a strong desire has effects like those of a weak desire, or vice versa. In the case of holistic theories, so long as desire strength is not reduced to strength of a single phenomenon, there is no contradiction in holding that a strong desire has one or a few effects like those of a weak desire, or vice versa. It is when theories reduce desires to a single observable core phenomenon that apparently meaningless fluctuations in that phenomenon pose a problem.