There is no point to reading your horoscope.
1 However, we should note that Avicenna maintains that the motions of the celestial bodies are also the causes of our acts of choice, not simply as occasions, as was said above, but directly. For he claims that the celestial bodies are animated. Hence, since celestial motion is from a soul and is the motion of a body, therefore, just as it is a bodily motion with the power of causing change in bodies, so as a motion from the soul it must have the power to make an impression on our souls. And thus, the celestial motion is the cause of our acts of will and choice. On this point also he seems to return to the theory of Albumasar, in his Introduction I.
2 But this theory is not reasonable. Every effect proceeding through an instrument from an efficient cause must be proportionate to the instrument, as also to the agent, for we cannot use just any instrument for any effect. Hence, a result cannot be accomplished by means of an instrument if the action of the instrument in no way covers the result. Now, the action of a body in no way extends to the production of a change of understanding and will, as we showed, unless, perchance, by accident, through a change in the body, as we said before. So, it is impossible for the soul of a celestial body, if it be animated, to make an impression on the intellect and will by means of the motion of a celestial body.
Notes In other words, the stars might have some physical effect on you, however small, but your will is still free. The next delightful argument proves this.
3 Again, a particular agent cause, when acting, bears a likeness to the universal agent cause and is patterned on it. But, if a human soul were to impress another human soul through a corporeal operation, as when it reveals its thought by means of meaningful speech, the bodily action initiated by one soul does not reach the other soul without the mediation of its body. In fact, the spoken word moves the auditory organ, and then, having been so perceived by the sense power, it extends its message to the understanding. So, if the celestial soul makes an impression on our souls through bodily movement, that action will not reach our soul without making a change in our body. Now, this is not a cause of our acts of choice, but simply an occasion, as is clear from the foregoing. Therefore, celestial motion will not be a cause of our act of choice, except as a mere occasion.
4 Besides, since the mover and the thing moved must be simultaneous, as is proved in Physics VII the motion must extend in a definite order, from the first mover to the last thing that is moved; that is, such that the mover moves what is far away from it by means of what is near to it.
Now, our body is nearer than our soul is to the celestial body which is asserted to be moved by a soul joined to it, for our soul has no relation to a celestial body except through our body. This is evident from the fact that separate intelligences have no relation to a celestial body, unless, perhaps, that of a mover to a thing moved. So, a change in a celestial body, initiated by its soul, does not reach our soul except through the mediation of our body. But our soul is not moved when our body is moved, except accidentally; nor does choice result from a change in our body, except by way of occasion, as we said. Therefore, celestial motion, by virtue of the fact that it is from a soul, cannot be the cause of our act of choice.
5 Moreover, according to the theory of Avicenna and some other philosophers, the agent intellect is a separate substance that acts on our souls by making potentially understood things to be actually understood. Now, this is done by abstraction from all material conditions, as is evident from our explanations in Book Two. So, that which acts directly on the soul does not act on it through corporeal motion, but, rather, through abstraction from everything corporeal. Therefore, the soul of the heavens, if it be animated, cannot be the cause of our acts of choice or understanding through the motion of the heavens.
6 It is also possible to prove by the same arguments that the motion of the heavens is not the cause of our acts of choice by means of separate substances, if someone claims that the heavens are not animated, but moved by a separate substance.